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sooks
kreegan...his response to my last example i think showed his complete idiocy to physics and any logical thought.
krreagan
QUOTE (sooks+Mar 6 2006, 09:59 PM)
QUOTE (Atl5p+Mar 7 2006, 04:49 AM)
QUOTE (sooks+Mar 6 2006, 03:58 PM)
if you cant see the relevance to this..than you prob dont have any business debating the entire issue... however with that said.. it is relevant because the rope is liek the engine.  all the engine does is push/pull the center of mass... it doesnt deal with the wheels...,

and the point is is taht the belts speed doesnt greatly affect the person from moving... the belt could be moving 200 mph...hed still get pulled over the edge.

That's funny, because I just tried this over the edge of my driveway...I made a pully, stood on the treadbelt and dropped the rock off...I didn't get 'pulled' over.

Oh, BTW the rock weighed 1 oz.

Care to try it with 2 oz? soooooooookkkkksssssss???????

time to make a stand....

hahha...are you kidding me...
A. i dont believe you tried this experiment for one second..

b. is your driveway a cliff???

c. are you on a treadbelt??

d. are you on rollerskates.

e. 1 oz.. are you frickin serious what did you use a pebble.. thats liek the weight of a feather.

f. how on earth did you tie a rope to a rock thats that small...

g. why on earth do you think 1 oz is going to move you.... how about you try something thats heavier than you in order to move you....idiot

wow... that was my QA on your experiment in a grand total of 1 minute and 15 seconds...you cant QA anything of any importance

Just like everything else... He's full of sh1t!

Krreagan
egnorant
QUOTE (Atl5p+Mar 7 2006, 04:38 AM)
QUOTE (Guest+Mar 6 2006, 03:53 PM)
Of course he'll be pulled over, but what's that got to do with the question!!

It was mentioned a while back that an analogy is like a boat on a river against a current. You could attach a rope to the boat and walk along the bank, pulling the boat behind you. There's nothing that could stop you from pulling the boat up the river. But again, what's this got to do with the question!?!

If you put a sail on the boat and the wind power equaled the river's current, the boat would be going nowhere.

This guy is actually a little cookoo...

if you think there's nothing stopping you from pulling a boat up river against a current, then you obviously have never seen whitewater rapids...imagine trying to pull an ocean freighter UP a whitewater rapid style current...meet you in St. Louie!! HAHAHA good luck. Has a bit to do with how fast the current is moving and how heavy (or Mass for some) the object in question.

and yes, the treadbelt would prevent you from falling off of that cliff...the bigger the rock, the faster the treadelt would have to go...by definition, if the treadbelt is holding you static to the calm air, then it is matching your speed as you travel over the surface of that 'never-ending' belt....

it IS coming...the end is near...

Actually it is ATL5p who is a little cuckoo..(cookoo..whatever!)
His obsession is to confuse and deflect.
All his theories have shot down so he welcomes any new voice that might be swayed by his murky statements.
I was sure we had honed his skills on this subject to a fine edge.
When pinned down on a particular train of thought he was good about misdirection.

Once he even resorted to name calling and vulgarities!
I'm glad he didn't pursue that as it was unbecoming of a true modern sophist.
Such a bold statement as "The tread belt will prevent you from falling off that cliff"
is a serious setback to his style.

I expect better of you.....be creative....I don't appreciate tantrums from you!!
Many of your posts showed true thought and specious reasoning.
I still have 20 days left on my medical leave and I expect to be entertained!!

By the way folks...It flies...and rather well!

Bruce
krreagan
QUOTE (Atl5p+Mar 6 2006, 09:38 PM)
This guy is actually a little cookoo...

And you would be the expert on those qualifications of course.

Krreagan
Atl5p
QUOTE (krreagan+Mar 6 2006, 09:06 AM)
QUOTE (krreagan+Mar 4 2006, 11:03 AM)
Atl5p... I see you have your deflector shields up!
QUOTE
1) Do you really believe that water currents have no effect upon a boat that is under sail power, vs currents DO have an effect on the same boat when it is under propeller power?
Does it really matter Where the force is applied to?  Air vs surface medium?
Does a treadbelt 'hold back' a car, just because it's wheel propelled, but won't hold back a plane, just because it's air propelled?

I was clear in these posts when they were discussed! If you think I was incorrect quote me in complete context and prove me wrong! Part of why I'm doing this is to make you actually read and understand the concepts that you argued about! As I do not believe you understand many of the concepts that you are trying to prove others wrong about!
QUOTE (->
 QUOTE 1) Do you really believe that water currents have no effect upon a boat that is under sail power, vs currents DO have an effect on the same boat when it is under propeller power?Does it really matter Where the force is applied to?  Air vs surface medium?Does a treadbelt 'hold back' a car, just because it's wheel propelled, but won't hold back a plane, just because it's air propelled?

I was clear in these posts when they were discussed! If you think I was incorrect quote me in complete context and prove me wrong! Part of why I'm doing this is to make you actually read and understand the concepts that you argued about! As I do not believe you understand many of the concepts that you are trying to prove others wrong about!
2) Do you really believe that it takes the SAME force/thrust/power to move a mass on the moon horizontally vs that same mass horizontally on the earth (at the same speed, ignoring air resistance)?
Does an object's Weight have anything to do with force required to propel, or is it all about Mass? (imagine the movie 2001 Space Odyssey, where they already have an airport with
runways paved out....)

All right... to make this easy for you I'll clarify this one point as simply and clearly as I can!...

Imagine a 100kg mass block on the the surface of the moon, the surface of the earth and in orbit around the earth.. All are on an imaginary frictionless table (this includes no air friction), well not the one in orbit of course, it's floating freely...

Now accelerate the block perpendicular to the gravitational vectors (horizontal) to a velocity of 1mps and hold that velocity for 1 sec, then accelerate the block back to 0mps over a period of 1 sec. Simple enough! Now it does not matter where you are, Earth, moon, orbit, deep space... the forces required for all situations are the same! This shows that accelerating or maintaining a constant velocity, the forces are the same!
QUOTE
EXPERIMENTS

I've answered all your "experiments" questions already! and will not do it again... I will also not let you off the hook with a "well I misunderstood the original conditions..." BS!

My arguments stand on their own! YOURS DON'T!

QUOTE (->
 QUOTE EXPERIMENTS

I've answered all your "experiments" questions already! and will not do it again... I will also not let you off the hook with a "well I misunderstood the original conditions..." BS!

My arguments stand on their own! YOURS DON'T!

Also, please verify an earlier post...the 'toy plane' in this experiment doesn't really need to be capable of actual flight, right? As long as it is propelled by the air, and it's wheels are 'free wheel'in', right?
Can you verify this as an actual statement you've made?

Find what I said on this! This is called research! Your statements about my "BS" were based on previous posts... If you did not understand them, you should have spoken up before spouting off!.

QUOTE
Do you see where I'm going with this? Are you starting to get a sinking feeling?

Actually yes! you want me to clearify all the positions so the you can then say "I misunderstood the conditions...". BS! , What I have said in the past is what you are here to attack! I'm starting to see you twist in the wind...
QUOTE (->
 QUOTE Do you see where I'm going with this? Are you starting to get a sinking feeling?

Actually yes! you want me to clearify all the positions so the you can then say "I misunderstood the conditions...". BS! , What I have said in the past is what you are here to attack! I'm starting to see you twist in the wind...
I already see that Sooks and Kreegan Disagree on one big point on the moon, so what's up?

Some disagreements are to be expected during any extended conversation... When you don't understand any of the concepts being discussed, I would expect disagreements with most of the concepts discussed! as you have!

You are ignorant of basic scientific concepts and refuse to admit it!

QUOTE
I encourage all 'Fly Boys' to give their stance on the above question...I mean, this is pretty much all of you against one of me, right? I mean, I would consider it to be sort of like 'backing down' if any consistant 'Fly Boy' can't give their thoughts above....it's simple and quick and once and for all....Fynlcut, sooks, newton...any others??? Cmon, it'll be fun! I already see that Sooks and Kreegan Disagree on one big point on the moon, so what's up?

You keep wanting to drag other people into this! They are more then welcome to comment on anything I have said and they have, but this is about you and your ignorance not their opinions! You have had "advocates" in the past and they are also welcome to comment but again this is about you! not them!

To reiterate!
QUOTE (->
 QUOTE I encourage all 'Fly Boys' to give their stance on the above question...I mean, this is pretty much all of you against one of me, right? I mean, I would consider it to be sort of like 'backing down' if any consistant 'Fly Boy' can't give their thoughts above....it's simple and quick and once and for all....Fynlcut, sooks, newton...any others??? Cmon, it'll be fun! I already see that Sooks and Kreegan Disagree on one big point on the moon, so what's up?

You keep wanting to drag other people into this! They are more then welcome to comment on anything I have said and they have, but this is about you and your ignorance not their opinions! You have had "advocates" in the past and they are also welcome to comment but again this is about you! not them!

To reiterate!
with conventional generally accepted equations, methodologies, terminology...

Krreagan

So Atl5p,

I guess this was the best you had? When you cannot claim that "you misunderstood the problem" your just going to ignore the challenge? I guess you are well aware of your... how shall we say, shortcomings

Kreagan

kreegan, let's get one thing clear...you are not God...I've been on this thread since page 30 something and I've heard and read enough to know the general jist of your stance on these issues....I just wanted to make absolutely clear.

For example, several days ago I did go back and research your posts on currents and boats and moving things on the moon, and I found many of the things you said to be evasive, and mostly insulting.

What I have done here is given you a forum to list out all of your ideas in one place on the topics mentioned above. You have done so.

Just to be clear, I take it that:

1) You believe that a sail boat has no mind of a current, however when the sail comes down and the motor turns on, the currents suddenly have their way with the, now, powerboat.

2) You believe that an electric car on earth will do 0 to 60mph in 20 seconds...and on the moon it will do 0 to 60mph in 20 seconds.

3) You believe that a plane that holds itself 'static' on a 10mph treadbelt, that same plane would only go about 1mph on a static runway.

4) You believe that a plane that goes 10mph on a static runway would need a belt speed of 1,000mph to hold the plane at 0 IAS

Kreegan, I'm really not sure why you are being so defensive; with all this "you cannot claim that "you misunderstood the problem"" business....I'm not trying to 'claim I don't understand the problem'...I'm just trying to focus in on what your beliefs of the issues are. Sort of like, yeah, we've hashed it out for awhile now, so in summary, what are you thoughts on the following items. Business and professional people do it every day...why are you making it such a big deal?

You are the one who issued the challenge. I simply asked for some clarification before answering that challenge. So...1-4 above...do I have you pegged down? Or are you just trying to be slippery? Whatever we do, it needs to be drawn back to a centralized place. You asked me to challenge you beliefs. Write up a contract. What are your beliefs? All you have to do is answer the questions, or just like in court, you will be tried in absentia. Everything that happened before is history...you have issued a challenge...I take that very seriously, and therefore I get to help set the ground rules. The ground rules are that each of us must make definitive statements about our beliefs. There will be no rambling around in the woodshed to find quotes and contexts....simple questions...they need straightforward answers, before I will commence with your duel..

You have done nothing more than deflected, and prolonged your ultimate demise. Are you afraid to make a stand? Why not answer a list of carefully worded questions like that? Too much risk for you to stomach?

And BTW asswhole...I'm not the one dragging everyone into this...that was YOU when you publicly issued a challenge to me. If it really WAS just between you and I, then you would have IM'ed me. But you didn't, so it's not...get over yourself...most people on this board disagree with half of what you say..and I agree with them and then some...
Atl5p
QUOTE (sooks+Mar 6 2006, 11:59 PM)
QUOTE (Atl5p+Mar 7 2006, 04:49 AM)
QUOTE (sooks+Mar 6 2006, 03:58 PM)
if you cant see the relevance to this..than you prob dont have any business debating the entire issue... however with that said.. it is relevant because the rope is liek the engine.  all the engine does is push/pull the center of mass... it doesnt deal with the wheels...,

and the point is is taht the belts speed doesnt greatly affect the person from moving... the belt could be moving 200 mph...hed still get pulled over the edge.

That's funny, because I just tried this over the edge of my driveway...I made a pully, stood on the treadbelt and dropped the rock off...I didn't get 'pulled' over.

Oh, BTW the rock weighed 1 oz.

Care to try it with 2 oz? soooooooookkkkksssssss???????

time to make a stand....

hahha...are you kidding me...
A. i dont believe you tried this experiment for one second..

b. is your driveway a cliff???

c. are you on a treadbelt??

d. are you on rollerskates.

e. 1 oz.. are you frickin serious what did you use a pebble.. thats liek the weight of a feather.

f. how on earth did you tie a rope to a rock thats that small...

g. why on earth do you think 1 oz is going to move you.... how about you try something thats heavier than you in order to move you....idiot

wow... that was my QA on your experiment in a grand total of 1 minute and 15 seconds...you cant QA anything of any importance

A. You have a right to believe what you want

B. My driveway has a very small cliff...it is about 1.5 inches high...the top is my driveway, and the bottom is the yard. it is a verticle drop. You didn't specify the height of the cliff, and it really dosn't matter now does it?

D. And likewise, the rollerskates

E. The one oz was a starting point. I handed it back to you at 2 oz. See, I gave you a 2 oz rock, and asked YOU to try. Then you hand me a 3 oz rock, and we'll SEE how much the rock must weigh to even budge us.
(and, btw, in order to move us, that rock would need to be a LOT lighter than half our weight. Since I weigh about 150, and the CRF of the skate wheels is 0.001, then we'll only need about 0.15 lbs of rock to propel us down the treadbelt.
Gee, I wonder how hard it would be at that time to 'Stop' me from moving? Umm, oh about 0.15 lbs I suppose. Pretty easy, even for a treadbelt.

So, now that we've proven that it can be done with a very light weight rock, and a slow moving treadbelt (cause that light rock wasn't moving us very fast to begin with, was it?)
All we need to do now is use bigger rocks, and faster treadbelt speeds (cause the bigger rocks will make us want to move faster, the treadbelt has to keep up).

Tell you what suuks...I'll let you and special-K throw out heavier and heavier 'rocks', and I'll just keep cranking up the treadbelt...

Like, you must belive that as long as you're pulling a boat up a river, and you are on the banks, that there is NOTHING the boat or currents could do to prevent you from pulling that boat up the river...(you DO believe that, don't you?)

psss..BTW, just between me and you, (don't tell kreegan...I know he's not reading cause he dosn't want to get dragged into other people's business)...anyway...I've got a better 'treadbelt plane' now...but I've said too much...

THE END IS NEAR>>>>MAKE YOUR PEACE WITH PHYSICS!!!
egnorant
And we get tantrums!!
Let me try a different approach.....sarcasm!
We really don't appreciate intelligent and clear explanations!!
Your logic and focus are getting old!!
Bruce
krreagan
QUOTE
kreegan, let's get one thing clear...you are not God...I've been on this thread since page 30 something and I've heard and read enough to know the general jist of your stance on these issues....I just wanted to make absolutely clear.

I've always maintained that I'm human and very capable of making errors! and I've been here since the 30's as well!

I disagree with the "clear" idea! You are deliberately muddying this up! You bring out examples that have little or no relevance to this topic. You never answer a direct question about your "theories" you use evasiveness to hide your ignorance by constantly deflecting questions without a clear answer!

QUOTE (->
 QUOTE kreegan, let's get one thing clear...you are not God...I've been on this thread since page 30 something and I've heard and read enough to know the general jist of your stance on these issues....I just wanted to make absolutely clear.

I've always maintained that I'm human and very capable of making errors! and I've been here since the 30's as well!

I disagree with the "clear" idea! You are deliberately muddying this up! You bring out examples that have little or no relevance to this topic. You never answer a direct question about your "theories" you use evasiveness to hide your ignorance by constantly deflecting questions without a clear answer!

For example, several days ago I did go back and research your posts on currents and boats and moving things on the moon, and I found many of the things you said to be evasive, and mostly insulting.

I was very clear! the reason they are confusing or unclear to you is due to your lack of knowledge on the subject that you so desperately want to be seen as knowledgeable (at least that is how it appears on the surface).

BTW: where are the quotes in context... If you actually did the reasearch (which I doubt).

QUOTE
What I have done here is given you a forum to list out all of your ideas in one place on the topics mentioned above.  You have done so.

Actually what you have done is made an azz of yourself by trying to argue a subject that you are ignorant of!

QUOTE (->
 QUOTE What I have done here is given you a forum to list out all of your ideas in one place on the topics mentioned above.  You have done so.

Actually what you have done is made an azz of yourself by trying to argue a subject that you are ignorant of!

Just to be clear, I take it that:

The problem is that you cannot be clear because you don't have the basic scientific knowledge to understand the concepts that I have used. Your examples show that you do not have a good (or even slight) grasp of the physics involved in this discussion.

QUOTE
1) You believe...

Again, this type of tactic will not work! I never said what you have (not)quoted here! you keep moving the context of what people say into you idiotic irrelevant and mostly wrong examples. Take what I said in context where I said it an prove me wrong. That is the challenge!

QUOTE (->
 QUOTE 1) You believe...

Again, this type of tactic will not work! I never said what you have (not)quoted here! you keep moving the context of what people say into you idiotic irrelevant and mostly wrong examples. Take what I said in context where I said it an prove me wrong. That is the challenge!

Kreegan, I'm really not sure why you are being so defensive; with all this "you cannot claim that "you misunderstood the problem"" business....I'm not trying to 'claim I don't understand the problem'...I'm just trying to focus in on what your beliefs of the issues are.  Sort of like, yeah, we've hashed it out for awhile now, so in summary, what are you thoughts on the following items.  Business and professional people do it every day...why are you making it such a big deal?

Defensive? Actually I'm on the offensive! I'm allowing you to stand up and proclaim your brilliance or ignorance! It's all up to you. You made your statements based on what was said earlier! That is what I challanged and you are evading! you cannot do what I have asked you to do so you are here evading the issue.

QUOTE
You are the one who issued the challenge.  I simply asked for some clarification before answering that challenge.  So...1-4 above...do I have you pegged down?  Or are you just trying to be slippery?

Do the reasearch! that is part of what this challange is all about!

QUOTE (->
 QUOTE You are the one who issued the challenge.  I simply asked for some clarification before answering that challenge.  So...1-4 above...do I have you pegged down?  Or are you just trying to be slippery?

Do the reasearch! that is part of what this challange is all about!

Whatever we do, it needs to be drawn back to a centralized place.  You asked me to challenge you beliefs.

No! you challenged the beliefs of hundreds of years of scientific reasearch and analysis... which I have studdied. My challenge was for you to prove me wrong in something I have said for which you are now deflecting! (and therefore proving that you cannot!)

QUOTE
Write up a contract.  What are your beliefs?  All you have to do is answer the questions, or just like in court, you will be tried in absentia.  Everything that happened before is history...you have issued a challenge...I take that very seriously, and therefore I get to help set the ground rules.  The ground rules are that each of us must make definitive statements about our beliefs.  There will be no rambling around in the woodshed to find quotes and contexts....simple questions...they need straightforward answers, before I will commence with your duel..

You are deflecting again! You may take the challenge seriously but you cannot put forth the science to complete the challenge, so you are here now writing up this legalese crap!

QUOTE (->
 QUOTE Write up a contract.  What are your beliefs?  All you have to do is answer the questions, or just like in court, you will be tried in absentia.  Everything that happened before is history...you have issued a challenge...I take that very seriously, and therefore I get to help set the ground rules.  The ground rules are that each of us must make definitive statements about our beliefs.  There will be no rambling around in the woodshed to find quotes and contexts....simple questions...they need straightforward answers, before I will commence with your duel..

You are deflecting again! You may take the challenge seriously but you cannot put forth the science to complete the challenge, so you are here now writing up this legalese crap!

You have done nothing more than deflected, and prolonged your ultimate demise.  Are you afraid to make a stand?  Why not answer a list of carefully worded questions like that?  Too much risk for you to stomach?

The challenge is not about what I believe! but what I have said and what you have (not) understood!

QUOTE
And BTW asswhole...I'm not the one dragging everyone into this...that was YOU when you publicly issued a challenge to me.  If it really WAS just between you and I, then you would have IM'ed me.  But you didn't, so it's not...get over yourself...most people on this board disagree with half of what you say..and I agree with them and then some...

You are the one that kept trying to get someone (anyone) to disagree with something I have said, I have only indicated that anyone (even your "no fly" buddies) are welcome to prove me wrong or to even state that they think I'm wrong! You have done this on many, many occasions and my challenge to you, was to have you prove that I said something inconsistent with currently accepted scientific theory. Considering how many posts I have on this discussion, I'm sure their are many, you only need to find one!

This forum is for entertainment! what fun would it be if you displayed your ignorance for only me to see! As several people have indicated, they get a lot of entertanment out of watching you on this forum, this includes me!

Krreagan

krreagan
QUOTE (Atl5p+Mar 6 2006, 10:58 PM)
psss..BTW, just between me and you, (don't tell kreegan...I know he's not reading cause he dosn't want to get dragged into other people's business)...anyway...I've got a better 'treadbelt plane' now...but I've said too much...

THE END IS NEAR>>>>MAKE YOUR PEACE WITH PHYSICS!!!

No, I'm just remaining focused on the challenge!

Many others on this list are equally capable of coaxing out your ignorance. It actually takes very little as you seem very willing to stand on a soap box and proclaim that the "world is flat"!

Krreagan
sooks
wow krreagan... that was quite the post.....

Atl i disagree with when you said most people disagree with half of what hes saying. I really dont think thats true... and i dont really like how you put it as us up aganist you. Im not really picking sides one vs the other. I will agree with or disagree with anyone when i belive/know they are right or wrong. I have called kreegan on stuff before... allbeit only once.. maybe twice... thats cuase hes usually spot on on what hes saying. And im sure hed do the same to me if he didnt think what id say to be true. much like anyone else on this board...
krreagan
QUOTE (sooks+Mar 7 2006, 10:14 AM)
wow krreagan... that was quite the post.....

Well... I'm getting tired of his constant misdirection BS.

He'll do anything he can, BUT give a straight answer to my (or anybody else's) challange because that would expose without a doubt (which he has pretty much already done in my eyes) that he is uneducated on this subject. Not to mention his intuition/common-sense is also one of someone that has not had any formal education in physics, and perhaps not any hard science at all. This is why he misses basic scientific concepts

He is obviously here to attest to his knowledge of physics (otherwise why is he arguing and not listening) but cannot substantiate that knowledge (by example) with anything concrete, so he constantly re-poses questons in an attempt to redefine the topics just enough that he almost never actually has to say anything of substance. When he does try to put something together it's almost laughable. (1.5in cliff, 200=200, ratios in place of trig operations...)

Krreagan
sooks
Yeah i pretty much agree with what youre saying. it erally just appears his motive is to antagonize and stir controversy and try to add confusion. Everytime a post comes up that proves him wrong he ignores it untill something else comes up that he can bank off of. but without him... i may have never of gotten the 300th page post . Its strange, around most you guys I feel like a youngster at only 23... but every time he posts i feel like a genius.
krreagan
QUOTE (sooks+Mar 7 2006, 03:06 PM)
but every time he posts i feel like a genius.

That's one thing he excels at...

Krreagan
Camofrog
First off, the plane will fly no prob.

I don't know if anyone mentioned these points before but I have two situations to bring up.

1. You conduct this experiment in a giant wind tunnel, which like the treadmill matches the speed of the wind moving through the jet turbines. THEN the jet would not take off.

2. Pick up a toy car or airplane or whatever. Walk over to a treadmill and turn it on. While holding the toy, press it down onto the treadmill so the wheels come into contact with it and begin to roll. Now push the toy forward slowly. Okay, it moves forward! Now turn the treadmill higher. Push the toy forward again. It still moves! No matter how fast you make your treadmill go, you'll still be able to push your car forward along it no problem. EXACT SAME DEAL with the "real" plane. The engines will still push it forward. The plane will take off.
egnorant
QUOTE (Camofrog+Mar 8 2006, 04:20 AM)
First off, the plane will fly no prob.

I don't know if anyone mentioned these points before but I have two situations to bring up.

1. You conduct this experiment in a giant wind tunnel, which like the treadmill matches the speed of the wind moving through the jet turbines. THEN the jet would not take off.

2. Pick up a toy car or airplane or whatever. Walk over to a treadmill and turn it on. While holding the toy, press it down onto the treadmill so the wheels come into contact with it and begin to roll. Now push the toy forward slowly. Okay, it moves forward! Now turn the treadmill higher. Push the toy forward again. It still moves! No matter how fast you make your treadmill go, you'll still be able to push your car forward along it no problem. EXACT SAME DEAL with the "real" plane. The engines will still push it forward. The plane will take off.

Had a little trouble wrapping my brain around the first example.
If the wind tunnel is blowing the opposite direction (headwind)...it will take off but not have any movement in relation to the ground other than up and down.

The part that got me was the matching of the "speed through the jet turbines"
The air actually accelerates as it goes through the engine so are we talking inlet speed or exhaust speed or somewhere in between?

I have visions of over speeding engines exploding and planes getting fired backwards out of the wind tunnel like a bullet.

Now a tailwind is a whole different adventure.

Second example is a sterling example of how the forces are applied.
Bruce

Camofrog
In the wind tunnel, I mean a headwind, yes. In that case, the plane could get off the ground -- it's got a 1000-mph wind traveling over its wings, after all -- but it won't move relative to the ground. That's because with a wind tunnel you are doing to the air and the jet engines what the conveyor belt would to the ground and the wheels of a car in the same situation -- you're moving the substrate that the vehicle needs to "push off" from in order to gain forward momentum.
sooks
Ive got an interesting question that is kind of along the lines of this thread.

What if a helicopter was on a giant turntable (like a huge record player) that matched the speed of the rotors??
krreagan
QUOTE (sooks+Mar 8 2006, 09:30 AM)
Ive got an interesting question that is kind of along the lines of this thread.

What if a helicopter was on a giant turntable (like a huge record player) that matched the speed of the rotors??

I'm sure the pilot would blow chunks long before there was any chance of getting off the ground.

Krreagan
Fynlcut
QUOTE (sooks+Mar 8 2006, 04:30 PM)
Ive got an interesting question that is kind of along the lines of this thread.

What if a helicopter was on a giant turntable (like a huge record player) that matched the speed of the rotors??

What direction is it turning?

*EDIT* If it turns the same direction the blades will spin twice as fast relative to a point off the turntable.

If it turns opposite the direction, then they will appear to not turn relative to a point off the turn table.

The speed of the rotors is directly linked to the engine via a transmission (geared drive). For any given throttle setting and the blades at a given AoA, the blades will be at a given RPM. This will not change in relation to the chopper. i.e. the chopper pilot will allways see the same rotor speed.

So all you will be doing is turning the body of the chopper and adding or countering RPM's in relation to the air around it.

I think
Fynlcut
QUOTE (krreagan+Mar 8 2006, 04:40 PM)
QUOTE (sooks+Mar 8 2006, 09:30 AM)
Ive got an interesting question that is kind of along the lines of this thread.

What if a helicopter was on a giant turntable (like a huge record player) that matched the speed of the rotors??

I'm sure the pilot would blow chunks long before there was any chance of getting off the ground.

Krreagan

Would this be before or after the redout?
sooks
finylcut...

I was thiking If it spins the same direction as the helicopter blades then they will look like they are not moving compared to the helicopter or to a bysstander but would still be spinning compared to the ground as the entire helicopter is rotating and still would be spinning relative the ground... and would lift...(althuogh it wouldnt be stable cause the helicopter is spinning too)

If its opposite the blades then wont appear to be spinning to a bystander or the ground but will to the helicopter and wont go anywhere.
krreagan
QUOTE (Fynlcut+Mar 8 2006, 09:53 AM)
QUOTE (krreagan+Mar 8 2006, 04:40 PM)
QUOTE (sooks+Mar 8 2006, 09:30 AM)
Ive got an interesting question that is kind of along the lines of this thread.

What if a helicopter was on a giant turntable (like a huge record player) that matched the speed of the rotors??

I'm sure the pilot would blow chunks long before there was any chance of getting off the ground.

Krreagan

Would this be before or after the redout?

Depends, on how close he/she is to the axis of rotation.

Krreagan
Guest
That helicopter question is a good one....but as long as the blades are 'spinning', wouldn't they be spinning in relation to the helicopter?

But that got me thinking...

What would happen if you got a car on a treadbelt...ran it up to 100mph (car stays 'stationary'....Then you took the car out of gear and into neutral, but kept the treadbelt at 100mph...what would happen to the car? Do you think it would keep 'coasting' on the treadbelt and stay in a static position? I think it will, because there isn't anything to make it go backwards...

Heck, you could even do that with a toy car on a treadbelt...run the belt up to full speed and hold it down on the treadbelt. Once you let go, what happens? It stays right there, for hours...
krreagan
QUOTE (Guest+Mar 8 2006, 09:09 PM)
That helicopter question is a good one....but as long as the blades are 'spinning', wouldn't they be spinning in relation to the helicopter?

But that got me thinking...

What would happen if you got a car on a treadbelt...ran it up to 100mph (car stays 'stationary'....Then you took the car out of gear and into neutral, but kept the treadbelt at 100mph...what would happen to the car?  Do you think it would keep 'coasting' on the treadbelt and stay in a static position?  I think it will, because there isn't anything to make it go backwards...

Heck, you could even do that with a toy car on a treadbelt...run the belt up to full speed and hold it down on the treadbelt.  Once you let go, what happens?  It stays right there, for hours...

Atl5p,

I take it that you have conceded my challenge?

Krreagan
Camofrog
QUOTE (Guest+Mar 9 2006, 04:09 AM)
That helicopter question is a good one....but as long as the blades are 'spinning', wouldn't they be spinning in relation to the helicopter?

But that got me thinking...

What would happen if you got a car on a treadbelt...ran it up to 100mph (car stays 'stationary'....Then you took the car out of gear and into neutral, but kept the treadbelt at 100mph...what would happen to the car?  Do you think it would keep 'coasting' on the treadbelt and stay in a static position?  I think it will, because there isn't anything to make it go backwards...

Heck, you could even do that with a toy car on a treadbelt...run the belt up to full speed and hold it down on the treadbelt.  Once you let go, what happens?  It stays right there, for hours...

In neutral, the car would roll backwards because of friction in the bearings and tires. Pretty quickly too I bet.
Guest
i've got a question.

let's say there is a plane on a very large conveyer belt? now the belt would spin backwards relative to the motion of the plane. granted, the plane would naturally want to move forward as if to take off. but, would the plane actually take off?
egnorant
QUOTE (Guest+Mar 9 2006, 06:06 AM)
i've got a question.

let's say there is a plane on a very large conveyer belt? now the belt would spin backwards relative to the motion of the plane. granted, the plane would naturally want to move forward as if to take off. but, would the plane actually take off?

Bruce
egnorant
QUOTE (sooks+Mar 8 2006, 04:30 PM)
Ive got an interesting question that is kind of along the lines of this thread.

What if a helicopter was on a giant turntable (like a huge record player) that matched the speed of the rotors??

My turn to be the silly guy...what if it was one of those helicopters that had jets on the tips of the blades?

How about...If spun fast enough in the right direction would it take off without starting the engine?

If we put the helicopter sideways in a river on the Moon, would it tow a hovercraft?

If we tied the helicopter down with half a piece of string would it only go halfway up?

If you used a helicopter with stacked contra-rotating blades with one blade pulling up and the other pulling down with the same force would it be easier or harder to
manually lift the helicopter?
If you dropped this same helicopter would if fall faster or slower?

So how many of you (insert incorrectly spelled compound vulgarity here)
"will (insert action of choice here..I prefer "float butter side up")"
(juvenile intelligence crack) still think that a blah..blah...blahhh...You get the picture!
Bruce

bintherdunthat
QUOTE (Atl5p+Mar 7 2006, 04:38 AM)
QUOTE (Guest+Mar 6 2006, 03:53 PM)
Of course he'll be pulled over, but what's that got to do with the question!!

It was mentioned a while back that an analogy is like a boat on a river against a current. You could attach a rope to the boat and walk along the bank, pulling the boat behind you. There's nothing that could stop you from pulling the boat up the river. But again, what's this got to do with the question!?!

If you put a sail on the boat and the wind power equaled the river's current, the boat would be going nowhere.

This guy is actually a little cookoo...

if you think there's nothing stopping you from pulling a boat up river against a current, then you obviously have never seen whitewater rapids...imagine trying to pull an ocean freighter UP a whitewater rapid style current...meet you in St. Louie!! HAHAHA good luck. Has a bit to do with how fast the current is moving and how heavy (or Mass for some) the object in question.

and yes, the treadbelt would prevent you from falling off of that cliff...the bigger the rock, the faster the treadelt would have to go...by definition, if the treadbelt is holding you static to the calm air, then it is matching your speed as you travel over the surface of that 'never-ending' belt....

it IS coming...the end is near...

let me get this strate.this person alt5 does not believe the plane will take off!?well i can honestly say when i came to this thread.........long.........long........ago!for a few pages i too was fooled!hehe!!but reason and common sense won out and i now happily side with "the flyers"!!hehe!!and sense i AM NOT gonna reread to find out if this glaring error listed as his 'reasons" has been already pointed out............tada!
does he not state that a man pulling a box over a carpet is a FAIR comparison to the OP'S original question!?so.....i have this to say about that one.THE BOX AINT GOT NO WHEELS FOOL!!hehe!!there.now i feel better already......right as rain!have a COOKIE.........YOU KOOKY!!of course if i am in anyway misinformed......then.......NEVERMIND!!hehe!!
Guest
QUOTE (Atl5p+Mar 7 2006, 05:58 AM)
QUOTE (sooks+Mar 6 2006, 11:59 PM)
QUOTE (Atl5p+Mar 7 2006, 04:49 AM)
QUOTE (sooks+Mar 6 2006, 03:58 PM)
if you cant see the relevance to this..than you prob dont have any business debating the entire issue... however with that said.. it is relevant because the rope is liek the engine.  all the engine does is push/pull the center of mass... it doesnt deal with the wheels...,

and the point is is taht the belts speed doesnt greatly affect the person from moving... the belt could be moving 200 mph...hed still get pulled over the edge.

That's funny, because I just tried this over the edge of my driveway...I made a pully, stood on the treadbelt and dropped the rock off...I didn't get 'pulled' over.

Oh, BTW the rock weighed 1 oz.

Care to try it with 2 oz? soooooooookkkkksssssss???????

time to make a stand....

hahha...are you kidding me...
A. i dont believe you tried this experiment for one second..

b. is your driveway a cliff???

c. are you on a treadbelt??

d. are you on rollerskates.

e. 1 oz.. are you frickin serious what did you use a pebble.. thats liek the weight of a feather.

f. how on earth did you tie a rope to a rock thats that small...

g. why on earth do you think 1 oz is going to move you.... how about you try something thats heavier than you in order to move you....idiot

wow... that was my QA on your experiment in a grand total of 1 minute and 15 seconds...you cant QA anything of any importance

A. You have a right to believe what you want

B. My driveway has a very small cliff...it is about 1.5 inches high...the top is my driveway, and the bottom is the yard. it is a verticle drop. You didn't specify the height of the cliff, and it really dosn't matter now does it?

D. And likewise, the rollerskates

E. The one oz was a starting point. I handed it back to you at 2 oz. See, I gave you a 2 oz rock, and asked YOU to try. Then you hand me a 3 oz rock, and we'll SEE how much the rock must weigh to even budge us.
(and, btw, in order to move us, that rock would need to be a LOT lighter than half our weight. Since I weigh about 150, and the CRF of the skate wheels is 0.001, then we'll only need about 0.15 lbs of rock to propel us down the treadbelt.
Gee, I wonder how hard it would be at that time to 'Stop' me from moving? Umm, oh about 0.15 lbs I suppose. Pretty easy, even for a treadbelt.

So, now that we've proven that it can be done with a very light weight rock, and a slow moving treadbelt (cause that light rock wasn't moving us very fast to begin with, was it?)
All we need to do now is use bigger rocks, and faster treadbelt speeds (cause the bigger rocks will make us want to move faster, the treadbelt has to keep up).

Tell you what suuks...I'll let you and special-K throw out heavier and heavier 'rocks', and I'll just keep cranking up the treadbelt...

Like, you must belive that as long as you're pulling a boat up a river, and you are on the banks, that there is NOTHING the boat or currents could do to prevent you from pulling that boat up the river...(you DO believe that, don't you?)

psss..BTW, just between me and you, (don't tell kreegan...I know he's not reading cause he dosn't want to get dragged into other people's business)...anyway...I've got a better 'treadbelt plane' now...but I've said too much...

THE END IS NEAR>>>>MAKE YOUR PEACE WITH PHYSICS!!!

Quote from Quote above by Atl5p:
QUOTE
Tell you what suuks...I'll let you and special-K throw out heavier and heavier 'rocks', and I'll just keep cranking up the treadbelt...

What allows you to "crank up the belt"? The speed of the vehicle(roller blades?) is motionless. the belt is dedicated to the vehicle. You can't simply speed up the belt at will. If the vehicle is motionless, then so is the belt.
Sheesh... He's still screwing up the idea of "belt matching speed of vehicle! He can't get past the idea that if the vehicle is motionless then its speed is ZERO and therefor the belt speed is ZERO.
swimmer
QUOTE (Guest+Mar 9 2006, 06:06 AM)
i've got a question.

let's say there is a plane on a very large conveyer belt? now the belt would spin backwards relative to the motion of the plane. granted, the plane would naturally want to move forward as if to take off. but, would the plane actually take off?

Yes... I've often wondered about that myself.

What a conundrum
Guest
QUOTE (Guest+Mar 9 2006, 01:40 PM)
QUOTE (Atl5p+Mar 7 2006, 05:58 AM)
QUOTE (sooks+Mar 6 2006, 11:59 PM)
QUOTE (Atl5p+Mar 7 2006, 04:49 AM)
QUOTE (sooks+Mar 6 2006, 03:58 PM)
if you cant see the relevance to this..than you prob dont have any business debating the entire issue... however with that said.. it is relevant because the rope is liek the engine.  all the engine does is push/pull the center of mass... it doesnt deal with the wheels...,

and the point is is taht the belts speed doesnt greatly affect the person from moving... the belt could be moving 200 mph...hed still get pulled over the edge.

That's funny, because I just tried this over the edge of my driveway...I made a pully, stood on the treadbelt and dropped the rock off...I didn't get 'pulled' over.

Oh, BTW the rock weighed 1 oz.

Care to try it with 2 oz? soooooooookkkkksssssss???????

time to make a stand....

hahha...are you kidding me...
A. i dont believe you tried this experiment for one second..

b. is your driveway a cliff???

c. are you on a treadbelt??

d. are you on rollerskates.

e. 1 oz.. are you frickin serious what did you use a pebble.. thats liek the weight of a feather.

f. how on earth did you tie a rope to a rock thats that small...

g. why on earth do you think 1 oz is going to move you.... how about you try something thats heavier than you in order to move you....idiot

wow... that was my QA on your experiment in a grand total of 1 minute and 15 seconds...you cant QA anything of any importance

A. You have a right to believe what you want

B. My driveway has a very small cliff...it is about 1.5 inches high...the top is my driveway, and the bottom is the yard. it is a verticle drop. You didn't specify the height of the cliff, and it really dosn't matter now does it?

D. And likewise, the rollerskates

E. The one oz was a starting point. I handed it back to you at 2 oz. See, I gave you a 2 oz rock, and asked YOU to try. Then you hand me a 3 oz rock, and we'll SEE how much the rock must weigh to even budge us.
(and, btw, in order to move us, that rock would need to be a LOT lighter than half our weight. Since I weigh about 150, and the CRF of the skate wheels is 0.001, then we'll only need about 0.15 lbs of rock to propel us down the treadbelt.
Gee, I wonder how hard it would be at that time to 'Stop' me from moving? Umm, oh about 0.15 lbs I suppose. Pretty easy, even for a treadbelt.

So, now that we've proven that it can be done with a very light weight rock, and a slow moving treadbelt (cause that light rock wasn't moving us very fast to begin with, was it?)
All we need to do now is use bigger rocks, and faster treadbelt speeds (cause the bigger rocks will make us want to move faster, the treadbelt has to keep up).

Tell you what suuks...I'll let you and special-K throw out heavier and heavier 'rocks', and I'll just keep cranking up the treadbelt...

Like, you must belive that as long as you're pulling a boat up a river, and you are on the banks, that there is NOTHING the boat or currents could do to prevent you from pulling that boat up the river...(you DO believe that, don't you?)

psss..BTW, just between me and you, (don't tell kreegan...I know he's not reading cause he dosn't want to get dragged into other people's business)...anyway...I've got a better 'treadbelt plane' now...but I've said too much...

THE END IS NEAR>>>>MAKE YOUR PEACE WITH PHYSICS!!!

Quote from Quote above by Atl5p:
QUOTE
Tell you what suuks...I'll let you and special-K throw out heavier and heavier 'rocks', and I'll just keep cranking up the treadbelt...

What allows you to "crank up the belt"? The speed of the vehicle(roller blades?) is motionless. the belt is dedicated to the vehicle. You can't simply speed up the belt at will. If the vehicle is motionless, then so is the belt.
Sheesh... He's still screwing up the idea of "belt matching speed of vehicle! He can't get past the idea that if the vehicle is motionless then its speed is ZERO and therefor the belt speed is ZERO.

Or...... If the roller blades are being pulled by a rock of sufficient weight toward the "cliff" at a speed of 2mph, then the belt is only moving opposite at 2mph. since the roller blades ARE moving toward the cliff......then it will reach the cliff and be pulled over.

Same thing with the plane....
If it is moving at sufficient speed to its "take off", say 60mph, then the belt is moving opposite at 60mph. The wheels are simply spinning as if the plane were going "downwind" taking of with a 60mph tailwind....
The only thing required for this is a very lengthy runway.

The REAL question is WHAT the plane is capable of.
Guest
Granted...floats or skis on a plane instead of wheels may make a plane designed for wheel use may fall below the friction threshold and not be able to reach the "liftoff" speed.
swimmer
ATL5P - as you are keen on setting up experiments with your treadbelt or conveyor belt and a model plane, why not give this a go?

The key element to your argument that the plane won't fly is that the treadbelt provides sufficient force to the plane to hold it back. Am I right?

So instead of a model plane, why not just put some free-wheeling object (model car, roller skate or whatever) on to your treadbelt. Preferably use something that you can easily add weight to without touching the wheels. Then either attach a rod or a length of cord to the free-wheeling object. The rod or cord has to be long enough to reach beyond the end of your treadbelt.

Now place a sensitive balance or weighing scales or similar next to one end of the treadbelt in such a way that you can measure the force being applied - either pushing via the rod or pulling via the cord. As you switch on and increase the speed of your treadbelt, continue to measure the force being applied to your scales.

Does the force increase with speed of the conveyor belt / treadbelt? Does it increase during the acceleration phase of your treadbelt i.e. as you switch it on or as you "crank up" its speed? What happens when you add weight to your freewheeling object?

sooks
See thats the problem. ATL thinks force equates to speed. He hasnt grasped this... or else he thinks that the questions states the belt can go as fast as it wants to match the force of the plane... nto really sure..either way hes missing something and refuses to admit his err's.
krreagan
QUOTE (krreagan+Mar 3 2006, 07:39 AM)
Atl5p,

I'm putting forth a challenge to you!

Prove me wrong!

That's it! It should be simple enough since you think that anything I say is bogus! If I'm as full of BS as you say I am, this should take about 10 seconds. But I'll bet you cannot do it (dipshit)!

All you have to do is find something that I have written in this forum that concerns a physical law or physical concept that pertains to the question at hand... and prove that I was wrong in the context that it was used!

I dare you to try!!!! And not with your usual BS "I said it's wrong, so its wrong" or with some roundabout example that only serves to confuse you even more, but with conventional generally accepted equations, methodologies, terminology...

I'm challenging you to prove me wrong and I'll leave OR you leave!

So the ball's in your court!

Krreagan

Atl5p,

Since you have not attempted to fullfill the conditions of my challenge, but did respond for your "clarifications" to indicate that you acknowledged the challenge. And, since I have not heard from you (except in stealth/guest mode I suspect) in the last several days, I therefore am going to assume that you have conceded/acknowledged your ignorance of the physics involved in the discussions of this forum and therefore have forfieted/ceded the challenge without even a single attempt to prove that my statements about your ignorance of physics, are incorrect!

Not a suprise!

Krreagan
Fynlcut
I think he is busy trying to get his new airplane to sit still on the treadmill!!
"Stay, dang, stay, dang, stay,dang,stay,dang,stay,dang..........."
krreagan
QUOTE (Fynlcut+Mar 9 2006, 11:52 AM)
I think he is busy trying to get his new airplane to sit still on the treadmill!!
"Stay, dang, stay, dang, stay,dang,stay,dang,stay,dang..........."

Ya, I think I can here the gears grinding off in the distance.

Krreagan
Guest
Will a plane with no engines (glider) in a wind tunnel take off, with the right amount of wind? Will it fly (hover) stationary in the tunnel? Or will it fly moving backwards in the wind tunnel?
Guest
QUOTE (Guest+Mar 9 2006, 08:40 PM)
Will a plane with no engines (glider) in a wind tunnel take off, with the right amount of wind? Will it fly (hover) stationary in the tunnel? Or will it fly moving backwards in the wind tunnel?

possibly ALL of the above....
Camofrog
Krreagan ...

Before you start calling other people ignorant let me just gently point out that your Mark Twain quote is riddles with errors, hence making you look a bit like a fool yourself ...
sooks
QUOTE (Camofrog+Mar 9 2006, 11:56 PM)
Krreagan ...

Before you start calling other people ignorant let me just gently point out that your Mark Twain quote is riddles with errors, hence making you look a bit like a fool yourself ...

*Riddled*... it is filled with errors... its not a puzzle or a joke of errors.. maybe you should proof read your own quote also....

but krregan, he is right,.. *then to speak and remove all doubt
krreagan
QUOTE (Camofrog+Mar 9 2006, 04:56 PM)
Krreagan ...

Before you start calling other people ignorant let me just gently point out that your Mark Twain quote is riddles with errors, hence making you look a bit like a fool yourself ...

The quote was copied from somewhere on-line...
And actually, the quotes origins are still not known for sure, Some attribute it to Mark Twain, some to Einstein, even Groucho Marx is listed as a possible source. The exact wording is also not known! So to say it is riddled with errors is actually not strictly correct either, unless of course you know _first hand_ who originally said it! The point of the phrase is nevertheless easy to understand.
That being said, you also look the fool for pointing out something that you yourself are unaware of: "Riddles"?.

My comments on Atl5p's ignorance comes from hundreds of pages of arguing with someone that has not either an education in physics or a rudimentary understanding of many physical concepts, as demonstraited by many of his bizare statements. (they are all there for everyone to see)
Ignorance of a subject is not in and of itself bad in anyway as I am also ignorant of may subjects. But when you come to a site as this and argue on and on about a subject that you have no idea about, and not for the purpose of educating himself but for some other unknown reason, He deserves what he gets!

Atl5p, is ignorant of physics! He is stubborn, arrogant, and in my own words, a dipshit!

If you have a problem with this, read several hundred pages of history on this topic!

Krreagan
krreagan
QUOTE (sooks+Mar 9 2006, 05:38 PM)
QUOTE (Camofrog+Mar 9 2006, 11:56 PM)
Krreagan ...

Before you start calling other people ignorant let me just gently point out that your Mark Twain quote is riddles with errors, hence making you look a bit like a fool yourself ...

*Riddled*... it is filled with errors... its not a puzzle or a joke of errors.. maybe you should proof read your own quote also....

but krregan, he is right,.. *then to speak and remove all doubt

Fixed!

After all, spelling and grammar are not my best subjects, But I'm allways willing to learn and improve!

Krreagan
Atl5p
QUOTE (Atl5p+Mar 7 2006, 12:45 AM)
QUOTE (krreagan+Mar 6 2006, 09:06 AM)
QUOTE (krreagan+Mar 4 2006, 11:03 AM)
Atl5p... I see you have your deflector shields up!
QUOTE
1) Do you really believe that water currents have no effect upon a boat that is under sail power, vs currents DO have an effect on the same boat when it is under propeller power?
Does it really matter Where the force is applied to?  Air vs surface medium?
Does a treadbelt 'hold back' a car, just because it's wheel propelled, but won't hold back a plane, just because it's air propelled?

I was clear in these posts when they were discussed! If you think I was incorrect quote me in complete context and prove me wrong! Part of why I'm doing this is to make you actually read and understand the concepts that you argued about! As I do not believe you understand many of the concepts that you are trying to prove others wrong about!
QUOTE (->
 QUOTE 1) Do you really believe that water currents have no effect upon a boat that is under sail power, vs currents DO have an effect on the same boat when it is under propeller power?Does it really matter Where the force is applied to?  Air vs surface medium?Does a treadbelt 'hold back' a car, just because it's wheel propelled, but won't hold back a plane, just because it's air propelled?

I was clear in these posts when they were discussed! If you think I was incorrect quote me in complete context and prove me wrong! Part of why I'm doing this is to make you actually read and understand the concepts that you argued about! As I do not believe you understand many of the concepts that you are trying to prove others wrong about!
2) Do you really believe that it takes the SAME force/thrust/power to move a mass on the moon horizontally vs that same mass horizontally on the earth (at the same speed, ignoring air resistance)?
Does an object's Weight have anything to do with force required to propel, or is it all about Mass? (imagine the movie 2001 Space Odyssey, where they already have an airport with
runways paved out....)

All right... to make this easy for you I'll clarify this one point as simply and clearly as I can!...

Imagine a 100kg mass block on the the surface of the moon, the surface of the earth and in orbit around the earth.. All are on an imaginary frictionless table (this includes no air friction), well not the one in orbit of course, it's floating freely...

Now accelerate the block perpendicular to the gravitational vectors (horizontal) to a velocity of 1mps and hold that velocity for 1 sec, then accelerate the block back to 0mps over a period of 1 sec. Simple enough! Now it does not matter where you are, Earth, moon, orbit, deep space... the forces required for all situations are the same! This shows that accelerating or maintaining a constant velocity, the forces are the same!
QUOTE
EXPERIMENTS

I've answered all your "experiments" questions already! and will not do it again... I will also not let you off the hook with a "well I misunderstood the original conditions..." BS!

My arguments stand on their own! YOURS DON'T!

QUOTE (->
 QUOTE EXPERIMENTS

I've answered all your "experiments" questions already! and will not do it again... I will also not let you off the hook with a "well I misunderstood the original conditions..." BS!

My arguments stand on their own! YOURS DON'T!

Also, please verify an earlier post...the 'toy plane' in this experiment doesn't really need to be capable of actual flight, right? As long as it is propelled by the air, and it's wheels are 'free wheel'in', right?
Can you verify this as an actual statement you've made?

Find what I said on this! This is called research! Your statements about my "BS" were based on previous posts... If you did not understand them, you should have spoken up before spouting off!.

QUOTE
Do you see where I'm going with this? Are you starting to get a sinking feeling?

Actually yes! you want me to clearify all the positions so the you can then say "I misunderstood the conditions...". BS! , What I have said in the past is what you are here to attack! I'm starting to see you twist in the wind...
QUOTE (->
 QUOTE Do you see where I'm going with this? Are you starting to get a sinking feeling?

Actually yes! you want me to clearify all the positions so the you can then say "I misunderstood the conditions...". BS! , What I have said in the past is what you are here to attack! I'm starting to see you twist in the wind...
I already see that Sooks and Kreegan Disagree on one big point on the moon, so what's up?

Some disagreements are to be expected during any extended conversation... When you don't understand any of the concepts being discussed, I would expect disagreements with most of the concepts discussed! as you have!

You are ignorant of basic scientific concepts and refuse to admit it!

QUOTE
I encourage all 'Fly Boys' to give their stance on the above question...I mean, this is pretty much all of you against one of me, right? I mean, I would consider it to be sort of like 'backing down' if any consistant 'Fly Boy' can't give their thoughts above....it's simple and quick and once and for all....Fynlcut, sooks, newton...any others??? Cmon, it'll be fun! I already see that Sooks and Kreegan Disagree on one big point on the moon, so what's up?

You keep wanting to drag other people into this! They are more then welcome to comment on anything I have said and they have, but this is about you and your ignorance not their opinions! You have had "advocates" in the past and they are also welcome to comment but again this is about you! not them!

To reiterate!
QUOTE (->
 QUOTE I encourage all 'Fly Boys' to give their stance on the above question...I mean, this is pretty much all of you against one of me, right? I mean, I would consider it to be sort of like 'backing down' if any consistant 'Fly Boy' can't give their thoughts above....it's simple and quick and once and for all....Fynlcut, sooks, newton...any others??? Cmon, it'll be fun! I already see that Sooks and Kreegan Disagree on one big point on the moon, so what's up?

You keep wanting to drag other people into this! They are more then welcome to comment on anything I have said and they have, but this is about you and your ignorance not their opinions! You have had "advocates" in the past and they are also welcome to comment but again this is about you! not them!

To reiterate!
with conventional generally accepted equations, methodologies, terminology...

Krreagan

So Atl5p,

I guess this was the best you had? When you cannot claim that "you misunderstood the problem" your just going to ignore the challenge? I guess you are well aware of your... how shall we say, shortcomings

Kreagan

kreegan, let's get one thing clear...you are not God...I've been on this thread since page 30 something and I've heard and read enough to know the general jist of your stance on these issues....I just wanted to make absolutely clear.

For example, several days ago I did go back and research your posts on currents and boats and moving things on the moon, and I found many of the things you said to be evasive, and mostly insulting.

What I have done here is given you a forum to list out all of your ideas in one place on the topics mentioned above. You have done so.

Just to be clear, I take it that:

1) You believe that a sail boat has no mind of a current, however when the sail comes down and the motor turns on, the currents suddenly have their way with the, now, powerboat.

2) You believe that an electric car on earth will do 0 to 60mph in 20 seconds...and on the moon it will do 0 to 60mph in 20 seconds.

3) You believe that a plane that holds itself 'static' on a 10mph treadbelt, that same plane would only go about 1mph on a static runway.

4) You believe that a plane that goes 10mph on a static runway would need a belt speed of 1,000mph to hold the plane at 0 IAS

Kreegan, I'm really not sure why you are being so defensive; with all this "you cannot claim that "you misunderstood the problem"" business....I'm not trying to 'claim I don't understand the problem'...I'm just trying to focus in on what your beliefs of the issues are. Sort of like, yeah, we've hashed it out for awhile now, so in summary, what are you thoughts on the following items. Business and professional people do it every day...why are you making it such a big deal?

You are the one who issued the challenge. I simply asked for some clarification before answering that challenge. So...1-4 above...do I have you pegged down? Or are you just trying to be slippery? Whatever we do, it needs to be drawn back to a centralized place. You asked me to challenge you beliefs. Write up a contract. What are your beliefs? All you have to do is answer the questions, or just like in court, you will be tried in absentia. Everything that happened before is history...you have issued a challenge...I take that very seriously, and therefore I get to help set the ground rules. The ground rules are that each of us must make definitive statements about our beliefs. There will be no rambling around in the woodshed to find quotes and contexts....simple questions...they need straightforward answers, before I will commence with your duel..

You have done nothing more than deflected, and prolonged your ultimate demise. Are you afraid to make a stand? Why not answer a list of carefully worded questions like that? Too much risk for you to stomach?

And BTW asswhole...I'm not the one dragging everyone into this...that was YOU when you publicly issued a challenge to me. If it really WAS just between you and I, then you would have IM'ed me. But you didn't, so it's not...get over yourself...most people on this board disagree with half of what you say..and I agree with them and then some...

Like I said earlier, special-K, I'm not going digging in the swamp for all your garbage...I asked you to give your points, and you did...(I guess)...For example, to the sail vs motor yacht question I looked...

QUOTE
The amount of force to overcome the force of the flowing water is (or to move a boat in still water) much less for a fan boat then a normal hulled boat! When the only force acting against either boat is the water flow, both will behave similarly When the water flow is being countered by thrust from a prop or fan, the fan boat (flat bottom) will require much less force to overcome the force of the water

Krreagan

well, thats nice and all...but it hardly answered the question, now did it??

"1) Do you really believe that water currents have no effect upon a boat that is under sail power, vs currents DO have an effect on the same boat when it is under propeller power?

Does it really matter [B]Where the force is applied to? Air vs surface medium?
Does a treadbelt 'hold back' a car, just because it's wheel propelled, but won't hold back a plane, just because it's air propelled?[

It's a VERY Simple question...

I mean, you CRITICIZED my statements on the subject, but you Never really Said ANYTHING!

Just abunchof smartass remarks.

You're a coward, Kreegan...take a stand on your beliefs on the subjects presented and then we'll duel...until then, I just don't have the time to go digging. I've been here...I've read all your posts...

If you want quotes, then why don't you go filter through all the wise cracks, and post the handfull of actual meaningful, thoughtful posts on theory.

So that's as good a place as any to start, kreetan.

I think it's BS

I think a boat going up a river is just like the plane on conveyor. I say it dosn't matter whether it's prop power, or sail power, the current will affect the respective boats the same.

What do you say? Did I hear you say somewhere that it DOES matter WHERE the force of propulsion comes from? Something about 'wheeled power can be held back, but air power can't be held back?

So when I put the car in neutral, doing 100mph, it's the wheel bearings that slow me down, plus the air resistance?

So what makes the car roll to a stop, when I'm only doing 10mph...with a 10mph tailwind? Are the bearings in a car's wheels Really that much worse than a plane's? What makes a plane 'roll to a stop', if not for the resistance of the tires? nevermind...

You NEVER answer these types of questions, which is why I won't even bother looking past page 4 of your records...I'm just not going to find much.

Here's your chance to TRULY Define yourself!!

All you have to do is explain how a car/plane is different from a sail/power boat! Simple!

THE END IS NEAR

egnorant
ATL5p nice to see you using your own name!

O.K. Now I am seeing correct answers being matched with the wrong questions!
Slick...there may be hope.
I also notice that you wisely avoid my posts and questions.
So I shall try again.
Boat question....
Take 2 identical boat that have both sail power and propeller power.
Current is flowing west at 10 knots.

With no power applied the current will soon be propelling both boats at 10 knots west.
Now we must make a few assumptions...
1. Wind exist (lets call it 10 knots of wind just to keep the formula simple)to move the boat east under sail at 10 knots without a current.
2. Boat has power to move at 10 knots east under power without a current.

Both these boats side by side...one cranks up the motor to 10 knots speed and it moves the boat against the current and makes no headway towards that island to the west.
With me so far!!
Other boat raises sails and it already has the advantage of an extra 10 knots of wind for power!!
Raise enough sail for only 5 knots and it blows past the power boat at 5 knots toward the island.
Turn the current around and have it heading towards the island and the power boat will blaze toward the island at 20 knots yet the sailboat will still be only able to move at 10 knots.

I know...What about water resistance?? Since the boats have identical hulls we can just factor them equally toward both boats.
I did see where krreagen said that different hulls are acted upon differently yet you disagreed...Strange
My Niece says Hi! and has a great analogy for your measuring the plane speed at the wheels delusion.
Bruce

1000 or bust!!!
sooks
Atl,

why is it you keep saying the end is near... are you finally realizing your wrong?? Because you have yet to prove me wrong. You are very good at your deversion tactics and answering questions with quesitons back. Every post that youve made with numbers has never been logical or even made sense. you put two random numbers and made them equal with no rhyme or reason. I dont understand why you keep up with these games... all you have to do is show with numbers and proper equations... how the force of friction is greater than thrust. the equation is simply crf * w... thats it. it can only imart a fraction of the force that its trying to exert. It has a limit. you can increase the speed and it doesnt do anything. so for the 747, its MAXIMUM friction force it can exert is 10,000 lbs. show me where thats wrong.

And means of propulsion is relevant. because a car propels itself through the wheels its wheels turn and must gain ground on the belt. Its wheels determine the speed of the car. So if the belt is matching the speed..its matching the wheels...the wheels can never gain any ground. A plane doenst use the wheels.. it shoots out the air and is propelled forward. the wheels dont determine the speed and therefore will revolve twice as fast..or cover twice the ground to move what it normally would off the belt. so means of propulsion does matter..

and yes..airline grade bearings are much better than car bearings.
Barkley
Wow, what a ridiculous thread, lol. Since there is no specificity in the original question, I must assume that this would be a glider of some sort and NOT propeller driven or jet engine propelled, since no aircraft of any type are dependent upon wheel drive propulsion. It is of my opinion that the aircraft would not "take off" as its lift is generated by airflow over and under the wings relative to the plane's airspeed and not artificial groundspeed.

In a sense, it would be akin to having an automobile on the conveyor belt running at some arbitrary speed and sticking your head out of the window. Guess what? Your hair won't be blowing back in your face because essentially, your are only remaining in place and not gaining since the belt cancels out any forward momentum and just the wheels are turning. A friend could walk right up to you and hand you a cup of coffee in either scenario since you are not actually travelling anywhere relative to the air or the ground.

Fynlcut
QUOTE (Barkley+Mar 10 2006, 09:18 AM)
Wow, what a ridiculous thread, lol. Since there is no specificity in the original question, I must assume that this would be a glider of some sort and NOT propeller driven or jet engine propelled, since no aircraft of any type are dependent upon wheel drive propulsion. It is of my opinion that the aircraft would not "take off" as its lift is generated by airflow over and under the wings relative to the plane's airspeed and not artificial groundspeed.

In a sense, it would be akin to having an automobile on the conveyor belt running at some arbitrary speed and sticking your head out of the window. Guess what? Your hair won't be blowing back in your face because essentially, your are only remaining in place and not gaining since the belt cancels out any forward momentum and just the wheels are turning. A friend could walk right up to you and hand you a cup of coffee in either scenario since you are not actually travelling anywhere relative to the air or the ground.

Wrongo!!

One thing we do know is that the plane is trying to take off. Ever seen a glider take off? Several ways this can happen

1) Aerotow. Probably the most common way. The glider is towed up by a prop driven plane, or tug. So does the tug start on the conveyor or off of it? Does it matter?

2) Static tow. The glider is pulled "kite-like" into the air by a winch system. Now is the winch on or off the conveyor?

3) Cliff launched. Blieve it or not some gliders you can get in a roll off a big hill, or cliff, some can even be launched by running of said hill. Ok so how do we get the hill on the conveyor?

4) A motor, some gliders simply extend their own motor, often hiden in a compartment just behind the canopy, start the engine and power up. Obviously we are now back to square one!

The only way the glider would not fly is:

1) If the winch system was on the conveyor and the conveyor ran at winch speed, (or some arbitrary speed where the forward pull of the winch was negated by the speed the winch approached the glider)

2) If you try to foot launch it from a conveyor on a hill.
Barkley
QUOTE (Fynlcut+Mar 10 2006, 10:14 AM)
QUOTE (Barkley+Mar 10 2006, 09:18 AM)
Wow, what a ridiculous thread, lol. Since there is no specificity in the original question, I must assume that this would be a glider of some sort and NOT propeller driven or jet engine propelled, since no aircraft of any type are dependent upon wheel drive propulsion. It is of my opinion that the aircraft would not "take off" as its lift is generated by airflow over and under the wings relative to the plane's airspeed and not artificial groundspeed.

In a sense, it would be akin to having an automobile on the conveyor belt running at some arbitrary speed and sticking your head out of the window. Guess what? Your hair won't be blowing back in your face because essentially, your are only remaining in place and not gaining since the belt cancels out any forward momentum and just the wheels are turning. A friend could walk right up to you and hand you a cup of coffee in either scenario since you are not actually travelling anywhere relative to the air or the ground.

Wrongo!!

One thing we do know is that the plane is trying to take off. Ever seen a glider take off? Several ways this can happen

1) Aerotow. Probably the most common way. The glider is towed up by a prop driven plane, or tug. So does the tug start on the conveyor or off of it? Does it matter?

2) Static tow. The glider is pulled "kite-like" into the air by a winch system. Now is the winch on or off the conveyor?

3) Cliff launched. Blieve it or not some gliders you can get in a roll off a big hill, or cliff, some can even be launched by running of said hill. Ok so how do we get the hill on the conveyor?

4) A motor, some gliders simply extend their own motor, often hiden in a compartment just behind the canopy, start the engine and power up. Obviously we are now back to square one!

The only way the glider would not fly is:

1) If the winch system was on the conveyor and the conveyor ran at winch speed, (or some arbitrary speed where the forward pull of the winch was negated by the speed the winch approached the glider)

2) If you try to foot launch it from a conveyor on a hill.

So then what is the propulsion mechanism for the plane to counteract the conveyor system? Let's say that the plane is a glider and is teathered so that only the landing gear wheels move yet the plane itself remains in place. This would amount to the same thing as the forward motion of a propulsion system would be negated by the opposite movement of the belt. The plane would not encounter lift necessary for flight, correct? No airborne vehicle here.

Next, if the propulsion system is a propeller driven piston motor, the uplift still shouldn't be encountered as the belt only negates the movement of the wheels and any uplift due to airflow over and under the wings is STILL not generated, right? This also results in a stationary plane. Moving along the ground only matters if a wind speed is generated, providing the necessary airflow for uplift. If not, please explain why not.

Normal civilian-type jet propulsion (not to be confused w/a ramjet nor a scramjet setup) might be a different scenario due to the direction of the exhaust plumes reacting upon a rather large ground surface area (not conveyor belt area) resulting in a spillover effect. What I mean here is the possibility of forward thrust due to friction on the surrounding ground area, which would constitute an opposing resistance, regardless of the moving conveyor belt. However, the compressed exhaust gas creates forward thrust (hence, lift) only IF the jet's velocity exceeds the aircraft flight velocity, like when a plane taxis from the jetway towards the runway.

In other words, the momentum of the air displaced by the wing is what gives it lift. How are we displacing air at the wing if the forward momentum is cancelled out by the conveyor belt, which basically keeps our aircraft stationary in the geographical sense? No air movement is achieved. Remember, we are talking about take off as opposed to already flying, so we consider this aircraft at a standstill as it relates to the ground. How would this aircraft achieve flight given the conveyor belt scenario and eliminating exhaust gas friction on the ground (spillover) propelling the frame forward? I very well could be wrong on this, so please explain.
isfn
QUOTE (Barkley+Mar 10 2006, 11:29 AM)
QUOTE (Fynlcut+Mar 10 2006, 10:14 AM)
QUOTE (Barkley+Mar 10 2006, 09:18 AM)
Wow, what a ridiculous thread, lol. Since there is no specificity in the original question, I must assume that this would be a glider of some sort and NOT propeller driven or jet engine propelled, since no aircraft of any type are dependent upon wheel drive propulsion. It is of my opinion that the aircraft would not "take off" as its lift is generated by airflow over and under the wings relative to the plane's airspeed and not artificial groundspeed.

In a sense, it would be akin to having an automobile on the conveyor belt running at some arbitrary speed and sticking your head out of the window. Guess what? Your hair won't be blowing back in your face because essentially, your are only remaining in place and not gaining since the belt cancels out any forward momentum and just the wheels are turning. A friend could walk right up to you and hand you a cup of coffee in either scenario since you are not actually travelling anywhere relative to the air or the ground.

Wrongo!!

One thing we do know is that the plane is trying to take off. Ever seen a glider take off? Several ways this can happen

1) Aerotow. Probably the most common way. The glider is towed up by a prop driven plane, or tug. So does the tug start on the conveyor or off of it? Does it matter?

2) Static tow. The glider is pulled "kite-like" into the air by a winch system. Now is the winch on or off the conveyor?

3) Cliff launched. Blieve it or not some gliders you can get in a roll off a big hill, or cliff, some can even be launched by running of said hill. Ok so how do we get the hill on the conveyor?

4) A motor, some gliders simply extend their own motor, often hiden in a compartment just behind the canopy, start the engine and power up. Obviously we are now back to square one!

The only way the glider would not fly is:

1) If the winch system was on the conveyor and the conveyor ran at winch speed, (or some arbitrary speed where the forward pull of the winch was negated by the speed the winch approached the glider)

2) If you try to foot launch it from a conveyor on a hill.

So then what is the propulsion mechanism for the plane to counteract the conveyor system? Let's say that the plane is a glider and is teathered so that only the landing gear wheels move yet the plane itself remains in place. This would amount to the same thing as the forward motion of a propulsion system would be negated by the opposite movement of the belt. The plane would not encounter lift necessary for flight, correct? No airborne vehicle here.

Next, if the propulsion system is a propeller driven piston motor, the uplift still shouldn't be encountered as the belt only negates the movement of the wheels and any uplift due to airflow over and under the wings is STILL not generated, right? This also results in a stationary plane. Moving along the ground only matters if a wind speed is generated, providing the necessary airflow for uplift. If not, please explain why not.

Normal civilian-type jet propulsion (not to be confused w/a ramjet nor a scramjet setup) might be a different scenario due to the direction of the exhaust plumes reacting upon a rather large ground surface area (not conveyor belt area) resulting in a spillover effect. What I mean here is the possibility of forward thrust due to friction on the surrounding ground area, which would constitute an opposing resistance, regardless of the moving conveyor belt. However, the compressed exhaust gas creates forward thrust (hence, lift) only IF the jet's velocity exceeds the aircraft flight velocity, like when a plane taxis from the jetway towards the runway.

In other words, the momentum of the air displaced by the wing is what gives it lift. How are we displacing air at the wing if the forward momentum is cancelled out by the conveyor belt, which basically keeps our aircraft stationary in the geographical sense? No air movement is achieved. Remember, we are talking about take off as opposed to already flying, so we consider this aircraft at a standstill as it relates to the ground. How would this aircraft achieve flight given the conveyor belt scenario and eliminating exhaust gas friction on the ground (spillover) propelling the frame forward? I very well could be wrong on this, so please explain.

Yes a plane needs airflow over the wings to fly which means it needs to move relative to the earth (in calm air). But what you are failing to see is that conveyor cannot prevent the plane from moving relative to the earth, the only thing it will do to the plane is make the wheels spin faster. Does that help?
Fynlcut
QUOTE (Barkley+Mar 10 2006, 11:29 AM)
QUOTE (Fynlcut+Mar 10 2006, 10:14 AM)
QUOTE (Barkley+Mar 10 2006, 09:18 AM)
Wow, what a ridiculous thread, lol. Since there is no specificity in the original question, I must assume that this would be a glider of some sort and NOT propeller driven or jet engine propelled, since no aircraft of any type are dependent upon wheel drive propulsion. It is of my opinion that the aircraft would not "take off" as its lift is generated by airflow over and under the wings relative to the plane's airspeed and not artificial groundspeed.

In a sense, it would be akin to having an automobile on the conveyor belt running at some arbitrary speed and sticking your head out of the window. Guess what? Your hair won't be blowing back in your face because essentially, your are only remaining in place and not gaining since the belt cancels out any forward momentum and just the wheels are turning. A friend could walk right up to you and hand you a cup of coffee in either scenario since you are not actually travelling anywhere relative to the air or the ground.

Wrongo!!

One thing we do know is that the plane is trying to take off. Ever seen a glider take off? Several ways this can happen

1) Aerotow. Probably the most common way. The glider is towed up by a prop driven plane, or tug. So does the tug start on the conveyor or off of it? Does it matter?

2) Static tow. The glider is pulled "kite-like" into the air by a winch system. Now is the winch on or off the conveyor?

3) Cliff launched. Blieve it or not some gliders you can get in a roll off a big hill, or cliff, some can even be launched by running of said hill. Ok so how do we get the hill on the conveyor?

4) A motor, some gliders simply extend their own motor, often hiden in a compartment just behind the canopy, start the engine and power up. Obviously we are now back to square one!

The only way the glider would not fly is:

1) If the winch system was on the conveyor and the conveyor ran at winch speed, (or some arbitrary speed where the forward pull of the winch was negated by the speed the winch approached the glider)

2) If you try to foot launch it from a conveyor on a hill.

So then what is the propulsion mechanism for the plane to counteract the conveyor system? Let's say that the plane is a glider and is teathered so that only the landing gear wheels move yet the plane itself remains in place. This would amount to the same thing as the forward motion of a propulsion system would be negated by the opposite movement of the belt. The plane would not encounter lift necessary for flight, correct? No airborne vehicle here.

Next, if the propulsion system is a propeller driven piston motor, the uplift still shouldn't be encountered as the belt only negates the movement of the wheels and any uplift due to airflow over and under the wings is STILL not generated, right? This also results in a stationary plane. Moving along the ground only matters if a wind speed is generated, providing the necessary airflow for uplift. If not, please explain why not.

Normal civilian-type jet propulsion (not to be confused w/a ramjet nor a scramjet setup) might be a different scenario due to the direction of the exhaust plumes reacting upon a rather large ground surface area (not conveyor belt area) resulting in a spillover effect. What I mean here is the possibility of forward thrust due to friction on the surrounding ground area, which would constitute an opposing resistance, regardless of the moving conveyor belt. However, the compressed exhaust gas creates forward thrust (hence, lift) only IF the jet's velocity exceeds the aircraft flight velocity, like when a plane taxis from the jetway towards the runway.

In other words, the momentum of the air displaced by the wing is what gives it lift. How are we displacing air at the wing if the forward momentum is cancelled out by the conveyor belt, which basically keeps our aircraft stationary in the geographical sense? No air movement is achieved. Remember, we are talking about take off as opposed to already flying, so we consider this aircraft at a standstill as it relates to the ground. How would this aircraft achieve flight given the conveyor belt scenario and eliminating exhaust gas friction on the ground (spillover) propelling the frame forward? I very well could be wrong on this, so please explain.

Ahh I see you are a "conveyor negates forward movement of the plane" kind of guy. Just exactly how does this happen?? Atl5P has been trying to explain this to no avail for the last 250 pages.

Remember the plane's engine, be it prop or jet or any combination there off, act upon the air. The same principal applies to the plane when it is on the ground or in the air. Regardless of engine type. The engine/airframe combo will run at a INDICATED AIRSPEED, regardless of wind or ground speeds. If you have no wind the plane will simply move forward to reach the same INDICATED AIRSPEED it would reach on a static runway. The distance it takes to reach this speed might change, but the fact it will reach this speed does not change.

The wheels will spin at the combined speed of the conveyor and plane (aka twice the speed of either the plane or conveyor.)

The whole part about the jet engine pushing off the ground (not the conveyor). Well I'm not sure what to make of that. Are you saying the jet will only move forward if the exhaust is directed to the ground? Well shoot how does the jet keep it's speed up at FL250?

QUOTE
In other words, the momentum of the air displaced by the wing is what gives it lift. How are we displacing air at the wing if the forward momentum is cancelled out by the conveyor belt, which basically keeps our aircraft stationary in the geographical sense? No air movement is achieved. Remember, we are talking about take off as opposed to already flying, so we consider this aircraft at a standstill as it relates to the ground. How would this aircraft achieve flight given the conveyor belt scenario and eliminating exhaust gas friction on the ground (spillover) propelling the frame forward? I very well could be wrong on this, so please explain.

Again how does the plane NOT move forward. What magical force does the conveyor pose that cancells out the thrust of the engine?
Barkley
OK, I guess that the original scenario of the "plane standing on the runway" was what confused me in that it implies starting from a standstill and as the opposing force (conveyor belt) moves in the opposite direction- as if freewheeling against forward momentum and ground travel- the plane would seemingly stay put relative to a fixed point. Reading it that way, this would indicate no net gain in forward movement. Hence, no generated wind speed necessary for lift.

At first impression, it would appear that the opposite movement of the conveyor belt would cancel out any forward progress of the plane from its standstill relative to a fixed point. Therefore, it seemingly would not allow the aircraft to generate any measureable airspeed (meaning no lift required for takeoff), as opposed to groundspeed. Lacking any clearly defined terms to measure aircraft speed further complicated the question. Thank you all for your patience.

312 pages, lol.
unclejim
Couldn't agree more with the '312 pages, lol'!

As it's so long and I'm new here, forgive me for not having read it all, but the confusion would seem to arise from the basic failing of the scenario given in the first post.
I quote:
'This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in opposite direction).'

If the conveyor tracks the speed of the plane, and the plane is stationary, the conveyor is stationary also, so what prevents the plane moving forward?
As the belt system acts to counter the movement of the plane, so it acts to reduce it's own influence on that movement; oh, dear, we have a circular argument...

The main problem, as pointed out by many, I'm sure, stems from a confused use of the word 'speed'.
The only applicable speed measurement I can think of would be the rearward speed of the airflow generated by the plane's engine which, I believe, is usually referred to as 'thrust'.

Also, in the scenario provided, the problem with a conventional aircraft and its interaction with our imaginary conveyor, is that the plane's wheels, which provide the only point of contact between the two, are freewheeling; entirely negating the rearward motion of the conveyor.

Soooo...
If we restate the original post as:

'A plane is fixed to a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane's engine thrust and tunes the speed of the conveyer to apply exactly the same force (but in opposite direction).'

Then we can legitimately state that the plane will not take off, as it is held stationary and can generate no lift.
Do be careful to note that this lack of take off has nothing to do with the plane being tethered to the conveyor, as, were no force applied, the engines would move both the plane and the conveyor forward just as if it were on wheels (yes I am deliberately ignoring the extra friction!), and, assuming the connection between plane and conveyor allowed for vertical movement,and the conveyor were long enough, the plane would eventually leave the ground.

I freely admit, however, that my version of the experiment is tediously obvious!
Fynlcut
QUOTE (unclejim+Mar 10 2006, 04:30 PM)

'A plane is fixed to a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane's engine thrust and tunes the speed of the conveyer to apply exactly the same force (but in opposite direction).'

Then we can legitimately state that the plane will not take off, as it is held stationary and can generate no lift.
Do be careful to note that this lack of take off has nothing to do with the plane being tethered to the conveyor, as, were no force applied, the engines would move both the plane and the conveyor forward just as if it were on wheels (yes I am deliberately ignoring the extra friction!), and, assuming the connection between plane and conveyor allowed for vertical movement,and the conveyor were long enough, the plane would eventually leave the ground.

I freely admit, however, that my version of the experiment is tediously obvious!

The more thrust you apply from the conveyor the faster the wheels spin. The conveyor can only transfer it's thrust to the wheels. Doesn't matter how fast the wheels spin. The plane will still move forward at XXX IAS
swimmer
QUOTE (swimmer+Mar 9 2006, 02:19 PM)
ATL5P - as you are keen on setting up experiments with your treadbelt or conveyor belt and a model plane, why not give this a go?

The key element to your argument that the plane won't fly is that the treadbelt provides sufficient force to the plane to hold it back. Am I right?

So instead of a model plane, why not just put some free-wheeling object (model car, roller skate or whatever) on to your treadbelt. Preferably use something that you can easily add weight to without touching the wheels. Then either attach a rod or a length of cord to the free-wheeling object. The rod or cord has to be long enough to reach beyond the end of your treadbelt.

Now place a sensitive balance or weighing scales or similar next to one end of the treadbelt in such a way that you can measure the force being applied - either pushing via the rod or pulling via the cord. As you switch on and increase the speed of your treadbelt, continue to measure the force being applied to your scales.

Does the force increase with speed of the conveyor belt / treadbelt? Does it increase during the acceleration phase of your treadbelt i.e. as you switch it on or as you "crank up" its speed? What happens when you add weight to your freewheeling object?

Come on ATL5P

The weekend is nearly upon us - plenty of time for you to do the experiment!!
egnorant
QUOTE (unclejim+Mar 10 2006, 04:30 PM)
'This conveyor has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in opposite direction).'

If the conveyor tracks the speed of the plane, and the plane is stationary, the conveyor is stationary also, so what prevents the plane moving forward?
As the belt system acts to counter the movement of the plane, so it acts to reduce it's own influence on that movement; oh, dear, we have a circular argument...

The main problem, as pointed out by many, I'm sure, stems from a confused use of the word 'speed'.
The only applicable speed measurement I can think of would be the rearward speed of the airflow generated by the plane's engine which, I believe, is usually referred to as 'thrust'.

As many have done before, you are replacing the term speed with thrust and the term matches with counteracts.
As for "the only applicable speed measurement" as thrust is just wrong.
Speed is just distance times time...Miles per hour is a good example.
Tether the plane down and crank up the engines it goes 0 miles per hour.
Lots of thrust but no speed.

Also nowhere in the question does it say the belt counteract the movement of the plane. It matches its speed!

The one question I have waited for anyone to answer is.....
If the plane never moves from its starting point in relation to itself (and the ground
and the calm air) how does it impart ANY speed to the wheels for the treadmill to MATCH?

This question is basic in my statement that if the belt must match the speed of the wheels, the only time this is possible from a standing start is if nothing moves.
Bruce

krreagan
Atl5pea-brain,
QUOTE
Like I said earlier, special-K, I'm not going digging in the swamp for all your garbage...I asked you to give your points, and you did...(I guess)...For example, to the sail vs motor yacht question I looked...

I thought you said you already did?? another BS statement on your part I presume!

lets see... here it is!
QUOTE (->
 QUOTE Like I said earlier, special-K, I'm not going digging in the swamp for all your garbage...I asked you to give your points, and you did...(I guess)...For example, to the sail vs motor yacht question I looked...

I thought you said you already did?? another BS statement on your part I presume!

lets see... here it is!
For example, several days ago I did go back and research your posts on currents and boats and moving things on the moon,

So, full of sh1t again I see!
QUOTE
You're a coward, Kreegan...

Is that why you refuse to accept my original challenge? because I am a coward? I guess this sort of makes sense considering the (il)logic that you have put forth in the past!
QUOTE (->
 QUOTE You're a coward, Kreegan...

Is that why you refuse to accept my original challenge? because I am a coward? I guess this sort of makes sense considering the (il)logic that you have put forth in the past!
take a stand on your beliefs on the subjects presented and then we'll duel...

That is what my challenge to you was all about!

You are the one that decided it was too difficult and you bailed. I have never waivered on my beliefs! You just cannot understand them because of your lack of knowledge/education and that is why you (alone, for the most point) think what I say is incorrect!

besides you seem to know better then I what I believe
QUOTE
1) You believe...
2) You believe...
3) You believe...
4) You believe...

QUOTE (->
 QUOTE 1) You believe...2) You believe...3) You believe...4) You believe...

You NEVER answer these types of questions, which is why I won't even bother looking past page 4 of your records...I'm just not going to find much.

I've answered 200+ pages of your nonsensical questions! They have little or no relevance to the question at hand! But that is all part of your strategy of deflection! when ever someone answers one of your posts, you (paraphrasing...) say BS and give another example that is farther and farther from the original question.

If you would prefer to dual on the original question, then go right ahead, No examples that do not address the original question (no cars, no boats, no orbits...) just a plane on a belt, period! Use only equations and theories that you can find in any physics-101 text book. be detailed and clear as you explain the interaction between objects. Do not deviate from this, as this has been your modus operandi in the past.

I'll even give you the first shot... Explain (in detail, with equations and physical theorems please) your interpretation of the outcome of the original question!

Just in case you forgot:

QUOTE
A plane is standing on runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in opposite direction).

The question is:

Will the plane take off or not? Will it be able to run up and take off?

Krreagan

PS, Hint: The boat problem...? Calculate the resistance a boat has at various speeds for different hull designs. Then calculate the the resistance that wheels/tires/bearings have for different shaped planes at different speeds...
If you actually do the math (which I'd bet money you couldn't do...) This should give you all the information needed to see why your analogy is idiotic and not relevant!
Atl5p
QUOTE
Krreagan

PS, Hint: The boat problem...? Calculate the resistance a boat has at various speeds for different hull designs. Then calculate the the resistance that wheels/tires/bearings have for different shaped planes at different speeds...
If you actually do the math (which I'd bet money you couldn't do...) This should give you all the information needed to see why your analogy is idiotic and not relevant!

Ohh...ok, I thought the Fly Boys were all saying that a fan boat on a river isn't affected by the current at all; but a motor boat would.

I really don't see the difference between the treadmill question and the river question.

A flat bottom boat with little resistance would be akin to very effecient tires or steel wheels and rails.

A deep hulled bottom boat would be like a huge earth moving machine's tires, OR tires from a monster truck (mounted of course, on a wind driven vehicle)

You do the math, since you're the physics instructor/flight sim developer....I'm just some guy who did a real world experiment...that's all....

And you still didn't give me a direct answer to the question...how typical...

THE END IS NEAR

Do you think...like Brucie, that a sail boat dosn't feel the current, but when the sail is drawn, and motor started, it now feels the current? That's what's on the table....you're about to loose big....
Atl5p
QUOTE (sooks+Mar 10 2006, 12:44 AM)
Atl,

why is it you keep saying the end is near... are you finally realizing your wrong?? Because you have yet to prove me wrong. You are very good at your deversion tactics and answering questions with quesitons back. Every post that youve made with numbers has never been logical or even made sense. you put two random numbers and made them equal with no rhyme or reason. I dont understand why you keep up with these games... all you have to do is show with numbers and proper equations... how the force of friction is greater than thrust. the equation is simply crf * w... thats it. it can only imart a fraction of the force that its trying to exert. It has a limit. you can increase the speed and it doesnt do anything. so for the 747, its MAXIMUM friction force it can exert is 10,000 lbs. show me where thats wrong.

And means of propulsion is relevant. because a car propels itself through the wheels its wheels turn and must gain ground on the belt. Its wheels determine the speed of the car. So if the belt is matching the speed..its matching the wheels...the wheels can never gain any ground. A plane doenst use the wheels.. it shoots out the air and is propelled forward. the wheels dont determine the speed and therefore will revolve twice as fast..or cover twice the ground to move what it normally would off the belt. so means of propulsion does matter..

and yes..airline grade bearings are much better than car bearings.

And I don't know how many times I have to explain this suuks...the tires don't HAVE to match the force of the plane...the TREADMILL does.

And with the weight of the plane on it, the treadmill must output that same 10,000 lbs of thrust/force/whatever, just to keep up speed with the plane.

Tell me...when the plane is going 50mph, how much force would the treadbelt need to go 50mph?

The treadbelt matches force, the tires are just a conduit...just a touch of friction can transfer the required force to repel the opposing object...

when I'm coasting in the car, what is slowing me down? After air resistance, what stops me that last 10mph? That's where your answer is...

krreagan
QUOTE (Atl5p+Mar 10 2006, 09:26 PM)
QUOTE
Krreagan

PS, Hint: The boat problem...? Calculate the resistance a boat has at various speeds for different hull designs. Then calculate the the resistance that wheels/tires/bearings have for different shaped planes at different speeds...
If you actually do the math (which I'd bet money you couldn't do...) This should give you all the information needed to see why your analogy is idiotic and not relevant!

Ohh...ok, I thought the Fly Boys were all saying that a fan boat on a river isn't affected by the current at all; but a motor boat would.

I really don't see the difference between the treadmill question and the river question.

A flat bottom boat with little resistance would be akin to very effecient tires or steel wheels and rails.

A deep hulled bottom boat would be like a huge earth moving machine's tires, OR tires from a monster truck (mounted of course, on a wind driven vehicle)

You do the math, since you're the physics instructor/flight sim developer....I'm just some guy who did a real world experiment...that's all....

And you still didn't give me a direct answer to the question...how typical...

THE END IS NEAR

Do you think...like Brucie, that a sail boat dosn't feel the current, but when the sail is drawn, and motor started, it now feels the current? That's what's on the table....you're about to loose big....

Atl5pea-brain,

Give up on the boat already it's a stupid example!

I gave you the option of another challenge that you don't have to do any research at all!

Are you too much of a chicken shlt to accept this one too?

Come on, I'm challenging you to an intellectual dual!

Do you accept or not????

If you answer with anything but a "yes" then I'll assume your answer is that you refuse my challenge (again)!

Krreagan
krreagan
QUOTE (Atl5p+Mar 10 2006, 09:36 PM)
QUOTE (sooks+Mar 10 2006, 12:44 AM)
Atl,

why is it you keep saying the end is near... are you finally realizing your wrong??  Because you have yet to prove me wrong.  You are very good at your deversion tactics and answering questions with quesitons back.  Every post that youve made with numbers has never been logical or even made sense.  you put two random numbers and made them equal with no rhyme or reason.  I dont understand why you keep up with these games... all you have to do is show with numbers and proper equations... how the force of friction is greater than thrust.  the equation is simply crf * w... thats it.  it can only imart a fraction of the force that its trying to exert.  It has a limit.  you can increase the speed and it doesnt do anything.  so for the 747, its MAXIMUM friction force it can exert is 10,000 lbs.  show me where thats wrong.

And means of propulsion is relevant.  because a car propels itself through the wheels its wheels turn and must gain ground on the belt.  Its wheels determine the speed of the car.  So if the belt is matching the speed..its matching the wheels...the wheels can never gain any ground.  A plane doenst use the wheels.. it shoots out the air and is propelled forward.  the wheels dont determine the speed and therefore will revolve twice as fast..or cover twice the ground to move what it normally would off the belt.  so means of propulsion does matter..

and yes..airline grade bearings are much better than car bearings.

And I don't know how many times I have to explain this suuks...the tires don't HAVE to match the force of the plane...the TREADMILL does.

And with the weight of the plane on it, the treadmill must output that same 10,000 lbs of thrust/force/whatever, just to keep up speed with the plane.

Tell me...when the plane is going 50mph, how much force would the treadbelt need to go 50mph?

The treadbelt matches force, the tires are just a conduit...just a touch of friction can transfer the required force to repel the opposing object...

when I'm coasting in the car, what is slowing me down? After air resistance, what stops me that last 10mph? That's where your answer is...

Atl5PEA-BRAIN,

What a freak'n IDIOT!

You haven't learned anything these past 300+ pages have you!
There is no way the force transferred through the wheels can have any more then the slightest effects on the plane! How is it going to counter the force ofthe jet engine??? You have been told this a hundred times by twenty different people, and you refuse to accept it because your pea brain cannot comprehend the physics involved!!!!!

God that felt good!

Krreagan
krreagan
QUOTE
THE END IS NEAR

You don't suppose he's a Hari Chrisna do ya?

Krreagan
sooks
QUOTE (Atl5p+Mar 11 2006, 04:36 AM)
QUOTE (sooks+Mar 10 2006, 12:44 AM)
Atl,

why is it you keep saying the end is near... are you finally realizing your wrong??  Because you have yet to prove me wrong.  You are very good at your deversion tactics and answering questions with quesitons back.  Every post that youve made with numbers has never been logical or even made sense.  you put two random numbers and made them equal with no rhyme or reason.  I dont understand why you keep up with these games... all you have to do is show with numbers and proper equations... how the force of friction is greater than thrust.  the equation is simply crf * w... thats it.  it can only imart a fraction of the force that its trying to exert.  It has a limit.  you can increase the speed and it doesnt do anything.  so for the 747, its MAXIMUM friction force it can exert is 10,000 lbs.  show me where thats wrong.

And means of propulsion is relevant.  because a car propels itself through the wheels its wheels turn and must gain ground on the belt.  Its wheels determine the speed of the car.  So if the belt is matching the speed..its matching the wheels...the wheels can never gain any ground.  A plane doenst use the wheels.. it shoots out the air and is propelled forward.  the wheels dont determine the speed and therefore will revolve twice as fast..or cover twice the ground to move what it normally would off the belt.  so means of propulsion does matter..

and yes..airline grade bearings are much better than car bearings.

And I don't know how many times I have to explain this suuks...the tires don't HAVE to match the force of the plane...the TREADMILL does.

And with the weight of the plane on it, the treadmill must output that same 10,000 lbs of thrust/force/whatever, just to keep up speed with the plane.

Tell me...when the plane is going 50mph, how much force would the treadbelt need to go 50mph?

The treadbelt matches force, the tires are just a conduit...just a touch of friction can transfer the required force to repel the opposing object...

when I'm coasting in the car, what is slowing me down? After air resistance, what stops me that last 10mph? That's where your answer is...

ATL,

Fine, ill accept that the belt exerts the same force to match the speed of the plane. But you have yet to explain or show where they interact with each other. As it sits, they are two seperate forces. So in our system. The plane exertts 200,000 lbs thrust. The belt exerts 200,000 to move. They dont exert 200,000 on each other. They cna only exert a fraction of that on each other through friction, by means of the FRICKIN friction equation crf * w which ive showed you many times that you keep ignoring. the belt only exerts 10,000 onto the plane. much the same as the plane oinly exerts 10,000 onto the belt... From what youre saying, the plane could prevent the belt from moving as well... it doesnt work that way. they dont act directly onto each other...jesus...... DO an eff'ing free body diagram...(if you know what that is)... and you will see that..the counteractive force is rolling friction..not the force of the belt!!!!
sooks
Use equations and show were wrong and youre right..all you have to do... Amazing you cant do it...
egnorant
The answer you are looking for is friction.
there is just not enough friction to transfer any meaningful power between the plane and the belt .

I ask my one question of you ATL5p...
If the plane never moves from its own starting point (stationary in relation to itself, ground, calm air and a non moving belt)....
How does it impart speed upon the wheels for the belt to match?

Since it cannot impart speed upon the wheels without moving away from this point the only time your no-fly version is valid is when nothing moves.

Bruce

P.S. I stand by my previous posts..even the one I got wrong.
You don't read to see if the posts are valid, you just look for opportunity to disagree.
swimmer
QUOTE (Atl5p+Mar 11 2006, 04:26 AM)
....I'm just some guy who did a real world experiment...that's all....

Great stuff, ATL5P! Have another go.

Come on, do the experiment I suggested.

QUOTE (swimmer @ Mar 9 2006+ 02:19 PM)

ATL5P - as you are keen on setting up experiments with your treadbelt or conveyor belt and a model plane, why not give this a go?

The key element to your argument that the plane won't fly is that the treadbelt provides sufficient force to the plane to hold it back. Am I right?

So instead of a model plane, why not just put some free-wheeling object (model car, roller skate or whatever) on to your treadbelt. Preferably use something that you can easily add weight to without touching the wheels. Then either attach a rod or a length of cord to the free-wheeling object. The rod or cord has to be long enough to reach beyond the end of your treadbelt.

Now place a sensitive balance or weighing scales or similar next to one end of the treadbelt in such a way that you can measure the force being applied - either pushing via the rod or pulling via the cord. As you switch on and increase the speed of your treadbelt, continue to measure the force being applied to your scales.

Does the force increase with speed of the conveyor belt / treadbelt? Does it increase during the acceleration phase of your treadbelt i.e. as you switch it on or as you "crank up" its speed? What happens when you add weight to your freewheeling object?

Maljonic
Why are so many people so fixated witht the treadmill, the way I read it was that the treadmill was just 'say' an example to illustrate that the plane can't move forwards. What if the plane rested on steel rollers instead that span in the opposite direction. Or if there was an arm at right angles to the plane which hel it securely in place so it can't go forwars or backward but can go up and down.

If there was a big fan in front of the plane with the arm attached, like in a wind tunnel, then obviously it would rise up into the air. Would the same thing happen just using the plane's engine/s?

Someone must have a model that they can easily rig up in this way, with a vertical-moving arm?
swimmer
QUOTE (Maljonic+Mar 11 2006, 11:58 AM)
Why are so many people so fixated witht the treadmill, the way I read it was that the treadmill was just 'say' an example to illustrate that the plane can't move forwards. What if the plane rested on steel rollers instead that span in the opposite direction. Or if there was an arm at right angles to the plane which hel it securely in place so it can't go forwars or backward but can go up and down.

If there was a big fan in front of the plane with the arm attached, like in a wind tunnel, then obviously it would rise up into the air. Would the same thing happen just using the plane's engine/s?

Someone must have a model that they can easily rig up in this way, with a vertical-moving arm?

That's what most people assume until they think about it.

Have a good old think about what is going on and you'll see that there is no way the conveyor (or steel rollers) can provide force to the plane to hold it back - they are not equivalent to an "arm at right angles holding it in place".
g
So, did anybody prove any physical laws wrong yet?

ATLidiot? I see that one's still trying.
MChat
I think the thing that most people who say the plane will not fly are missing is that there are two independent systems of force and resistance here BOTH of which affect the wheels. The thrust and forward movement affect the wheels through the spindle via the airframe; the conveyor affects the tires directly through frictional contact.

The first system of force/resistance is that of the aircraft's engines upon the atmosphere surrounding it. The engines create a low pressure area in front of the plane and a high pressure area in behind the plane. The difference in these pressures is what drives the plane forward and it will do this unless some other force prevents it. The wheels and wheelbearings (rolling resistance) here are an extremely small part of the resistance to this force. The main resistance to this force is the mass (not weight) of the aircraft itself and also wind resistance against the airframe of the aircraft, which increases as the speed of the aircraft increases. So long as the engines produce enough thrust to overcome these forces, the airplane will move forward.

The second system of force/resistance is that of the conveyor and the rolling resistance of the wheels. The conveyor acts upon the wheels with very little force, as not much force is needed to overcome the rolling resistance of the wheels and the wheelbearings. Because the wheels are not glued, nor are the brakes of the aircraft on the tires simply roll along the conveyor belt, making up for the speed difference between the aircraft and the conveyor belt; just as they would if it were a normal take off. The only difference is because the conveyor belt is moving in the opposite direction of the aircraft, the wheels are spinning twice as fast as normal.

Only when one incorrectly tries to combine the two force problems into one force problem does it appear the airplane does not move. A simple conveyor belt acting on the aircraft's wheels CAN NOT significantly affect the airspeed of the airplane. Some other force would be needed to counteract the thrust of the engines.

Saying that one force/resistance problem directly and significantly affects the other force problem is like saying the air conditioning unit in a sky scraper must be able to overcome the winds outside the sky scraper. The two are separate force/resistance systems with the only common link being the building; just as with the airplane, the only common link is the wheels. Both force/resistance problems directly affect the wheels, but neither force/resistance problem directly affects the other. Both act on the wheels which is why the wheels need to spin twice as fast as normal; one force acts to spin the wheels X amount and the other force also acts to spin the wheels X amount so the resulting WHEEL speed = X + X while the AIRSPEED of the aircraft and the speed of the conveyor belt both = X.

The conveyor does have a very minor effect against the thrust of the aircraft's engines, but this is limited to the the amount of force that can be applied through the rolling resistance of the aircraft. However, the conveyor would less of a chance of "holding back" the aircraft through this resistance than a Kia Spectra clutch (rated @ 100-something ft/lbs) would of holding the power of a top fuel dragster (in excess of 8000 ft/lbs).

Also, remember the problem states that the conveyor matches the speed of the aircraft and NOT the wheelspeed of the aircraft. If the conveyor DID attempt to match the wheelspeed, it would never be able to do so and both wheel-speed and conveyor-speed will accellerate at an exponential rate, yet the aircraft WILL move forward; that is until the tires disintegrate a few seconds into the run (so in that instance, the airplane would crash & burn rather than take off) However if we had tires, wheels and wheelbearings capable of an infinite wheelspeed at or near zero rolling resistance, then the aircraft would STILL take off and the wheels would simply be spinning incredibly fast as would the conveyor belt.
MChat
Also, I've given thought about this and changing the scenario to a normal wheel driven automobile and the common thinking that the car would remain motionless. This is only true if the speed of the conveyor is dictated by the wheelspeed. However, I don't believe that is the case from the original wording. It would appear that some device is used to determine the vehicles actual speed relative to the ground (a speed-radar perhaps).

If this is the case, then indeed the car would accellerate. The speedometer of the car would read twice the actual speed, but the car would be moving forward. In fact if the gearing of the car were changed to be 1/2 of what it is normally (e.g. 2.05 gears instead of 4.10's), the car would accellerate approximately at the same rate as normal (there would be some additional power loss incurred as a result of needing to spin the wheels 2x as fast as normal). Never the less the acceleration of the vehicle would be relatively unchanged, even without a gear swap, the only thing the motion of the conveyor would do is limit the top-speed of the car as the car would simply "run out of gear" (or at least any car with a decent amount of power would).
egnorant
QUOTE (MChat+Mar 14 2006, 02:15 PM)

Also, remember the problem states that the conveyor matches the speed of the aircraft and NOT the wheelspeed of the aircraft. If the conveyor DID attempt to match the wheelspeed, it would never be able to do so and both wheel-speed and conveyor-speed will accellerate at an exponential rate, yet the aircraft WILL move forward; that is until the tires disintegrate a few seconds into the run (so in that instance, the airplane would crash & burn rather than take off) However if we had tires, wheels and wheelbearings capable of an infinite wheelspeed at or near zero rolling resistance, then the aircraft would STILL take off and the wheels would simply be spinning incredibly fast as would the conveyor belt.

This is the one I have been fighting against.
If you figure it by wheel speed, if the plane ever moves in relation to its starting point, there will be a point where the belt is not matching the wheel speed.
This violates the Wheel speed theory. The question states that the belt matches the speed of the plane...not that it tries or catches up or that it can go faster.

Infinite speed people claim that the belt will speed up as it ATTEMPTS to match speed. This too is in violation of the wheel speed theory.

If the plane never moves from its starting point, it never has wheel speed for the belt to match.
If the plane does move from its starting point (even .5 inch) the belt can never match the speed.
Plane speed will then be ((X)+.5 inch) while belt speed will be only (X) for the distance formula of speed. Speed = distance times duration!
((X)+.5)=(X).....Around here we call that wrong!!
Wheel speed theory disproved.
Friction theory is moot as we assume that all components are capable of the function required....even the belt.
Bruce

MChat
QUOTE (egnorant+Mar 14 2006, 03:20 PM)
This is the one I have been fighting against.
If you figure it by wheel speed, if the plane ever moves in relation to its starting point, there will be a point where the belt is not matching the wheel speed.
This violates the Wheel speed theory. The question states that the belt matches the speed of the plane...not that it tries or catches up or that it can go faster.

Infinite speed people claim that the belt will speed up as it ATTEMPTS to match speed. This too is in violation of the wheel speed theory.

If the plane never moves from its starting point, it never has wheel speed for the belt to match.
If the plane does move from its starting point (even .5 inch) the belt can never match the speed.
Plane speed will then be ((X)+.5 inch) while belt speed will be only (X) for the distance formula of speed. Speed = distance times duration!
((X)+.5)=(X).....Around here we call that wrong!!
Wheel speed theory disproved.
Friction theory is moot as we assume that all components are capable of the function required....even the belt.
Bruce

The problem is that a conveyor being sped up to "match" the wheelspeed would never be able to. It is impossible, because the thrust of the aircraft's engines WILL move the aircraft forward.

In the real world there would need to be a sensor and a computer to "drive" the conveyor. If you used the quickest sensors and the quickest computer then the conveyor might update 1,000,000 times a second. However that means that there is one millionth of a second that the airplane's wheels move without the computer adjusting the speed of the conveyor. The only effect of this is that the wheel is now spinning twice as fast as it was previously, the aircraft is still moving forward. With the next millionth of a second, the conveyor speed is again increased to match the wheelspeed of the aircraft, but this too does not move the aircraft backward, but rather just continue to increase the wheelspeed. As you should be able to see, the aircraft will continue to move forward, and the wheelspeed will increase exponentially.

Let say, for instance, that the aircraft normally reaches a "take-off" velocity of 150ft/sec (~102mph) in 15 seconds and just for argument's sake that the aircraft's acceleration is linear, gaining 10ft/sec. Then normally the wheels would see a speed of 10fps at 1 second, 20fps at 2 seconds, 30fps at 3 seconds, etc... to 150fps at 15 seconds.

However if a wheel speed sensor is used to accelerate the "conveyor belt" and this sensor updates the speed of the conveyor belt once every second (for simplicity's sake) and assuming the "engine" driving the conveyor belt could keep up, then after the first second, the conveyor belt would be running at 10fps, doubling the 10fps of the wheel speed sensor on the aircraft. At the end of the 2nd second, the aircraft would have added another 10fps on top of the 20fps (10 for the aircraft, 10 for the conveyor belt) that the wheel speed sensors are reporting. So the conveyor will match that with 30fps for a total of 60fps.

For the 3rd second the conveyor adjusts for 70 fps (~48 mph).
For the 4th second the conveyor adjusts for 150 fps (~102 mph).
For the 5th second the conveyor adjusts for 310 fps (~211 mph).
For the 6th second the conveyor adjusts for 630 fps (~430 mph).
For the 7th second the conveyor adjusts for 1,270 fps (~866 mph).
For the 8th second the conveyor adjusts for 2,550 fps (~1,739 mph).
For the 9th second the conveyor adjusts for 5,110 fps (~3,484 mph).
For the 10th second the conveyor adjusts for 10,230 fps (~6,975 mph).
For the 11th second the conveyor adjusts for 20,470 fps (~13,957 mph).
For the 12th second the conveyor adjusts for 40,950 fps (~27,920 mph).
For the 13th second the conveyor adjusts to 81,910 fps (~55,848 mph).
For the 14th second the conveyor adjusts fo 162,820 fps (~111,014 mph).
And finally for the 15th second the conveyor adjusts for 327,670 fps or 223,411 mph.

Somewhere around the 5th second, the tires would likely give out. Of course the aircraft would only be traveling an actual 35mph, and the aircraft's landing gear would dig into the conveyor belt and then all heck would break loose...

In the hypotetical world where the conveyor COULD match the aircraft's wheels instantaniously then the instant the aircraft had any movement at all, the wheelspeed and conveyor speed would reach infinite speed. In the real world, the speed of the sensors and the speed of the computer and accelleration rate of the conveyor would determine just how quickly the wheelspeed increased. But given a conveyor capable of "keeping up" the quicker the sensor and computer cylce the quicker the accelleration rate of the wheels and conveyor. Yet, STILL the aircraft WILL move forward until the point at which the tires disintigrate. So given tires, wheels and wheelbearing capable of an infinite speed, the aircraft would still take off.
biplanepilot
MCHAT,

The wheel speed is the same as the conveyor speed as long as the two are in contact with each other. The whole key is airspeed. The speed of the air over the wings.
egnorant
QUOTE (MChat+Mar 14 2006, 03:53 PM)
The problem is that a conveyor being sped up to "match" the wheel speed would never be able to. It is impossible, because the thrust of the aircraft's engines WILL move the aircraft forward.

In the hypotetical world where the conveyor COULD match the aircraft's wheels instantaniously then the instant the aircraft had any movement at all, the wheelspeed and conveyor speed would reach infinite speed.

Even in this hypothetical world the belt could not match the wheel speed.
Question says it matches exactly!
The infinite speed scenario is NOT matching exactly..it is merely trying to catch up.
Wheel speed theory as applied to this question is only correct at the 0 speed.
Any movement by the plane to achieve wheel speed will instantly develop an environment where matching speed is impossible. ((X)+y) does not=(X)....
Use any figures you want! As long as y represents the movement of the plane to achieve wheel speed. Remember that y=0 indicates no wheel speed, so X must be 0 also.
It flies
Bruce

Guest
QUOTE (MChat+Mar 14 2006, 03:53 PM)
QUOTE (egnorant+Mar 14 2006, 03:20 PM)
This is the one I have been fighting against.
If you figure it by wheel speed, if the plane ever moves in relation to its starting point, there will be a point where the belt is not matching the wheel speed.
This violates the Wheel speed theory. The question states that the belt matches the speed of the plane...not that it tries or catches up or that it can go faster.

Infinite speed people claim that the belt will speed up as it ATTEMPTS to match speed. This too is in violation of the wheel speed theory.

If the plane never moves from its starting point, it never has wheel speed for the belt to match.
If the plane does move from its starting point (even .5 inch) the belt can never match the speed.
Plane speed will then be ((X)+.5 inch) while belt speed will be only (X) for the distance formula of speed. Speed = distance times duration!
((X)+.5)=(X).....Around here we call that wrong!!
Wheel speed theory disproved.
Friction theory is moot as we assume that all components are capable of the function required....even the belt.
Bruce

The problem is that a conveyor being sped up to "match" the wheelspeed would never be able to. It is impossible, because the thrust of the aircraft's engines WILL move the aircraft forward.

In the real world there would need to be a sensor and a computer to "drive" the conveyor. If you used the quickest sensors and the quickest computer then the conveyor might update 1,000,000 times a second. However that means that there is one millionth of a second that the airplane's wheels move without the computer adjusting the speed of the conveyor. The only effect of this is that the wheel is now spinning twice as fast as it was previously, the aircraft is still moving forward. With the next millionth of a second, the conveyor speed is again increased to match the wheelspeed of the aircraft, but this too does not move the aircraft backward, but rather just continue to increase the wheelspeed. As you should be able to see, the aircraft will continue to move forward, and the wheelspeed will increase exponentially.

Let say, for instance, that the aircraft normally reaches a "take-off" velocity of 150ft/sec (~102mph) in 15 seconds and just for argument's sake that the aircraft's acceleration is linear, gaining 10ft/sec. Then normally the wheels would see a speed of 10fps at 1 second, 20fps at 2 seconds, 30fps at 3 seconds, etc... to 150fps at 15 seconds.

However if a wheel speed sensor is used to accelerate the "conveyor belt" and this sensor updates the speed of the conveyor belt once every second (for simplicity's sake) and assuming the "engine" driving the conveyor belt could keep up, then after the first second, the conveyor belt would be running at 10fps, doubling the 10fps of the wheel speed sensor on the aircraft. At the end of the 2nd second, the aircraft would have added another 10fps on top of the 20fps (10 for the aircraft, 10 for the conveyor belt) that the wheel speed sensors are reporting. So the conveyor will match that with 30fps for a total of 60fps.

For the 3rd second the conveyor adjusts for 70 fps (~48 mph).
For the 4th second the conveyor adjusts for 150 fps (~102 mph).
For the 5th second the conveyor adjusts for 310 fps (~211 mph).
For the 6th second the conveyor adjusts for 630 fps (~430 mph).
For the 7th second the conveyor adjusts for 1,270 fps (~866 mph).
For the 8th second the conveyor adjusts for 2,550 fps (~1,739 mph).
For the 9th second the conveyor adjusts for 5,110 fps (~3,484 mph).
For the 10th second the conveyor adjusts for 10,230 fps (~6,975 mph).
For the 11th second the conveyor adjusts for 20,470 fps (~13,957 mph).
For the 12th second the conveyor adjusts for 40,950 fps (~27,920 mph).
For the 13th second the conveyor adjusts to 81,910 fps (~55,848 mph).
For the 14th second the conveyor adjusts fo 162,820 fps (~111,014 mph).
And finally for the 15th second the conveyor adjusts for 327,670 fps or 223,411 mph.

Somewhere around the 5th second, the tires would likely give out. Of course the aircraft would only be traveling an actual 35mph, and the aircraft's landing gear would dig into the conveyor belt and then all heck would break loose...

In the hypotetical world where the conveyor COULD match the aircraft's wheels instantaniously then the instant the aircraft had any movement at all, the wheelspeed and conveyor speed would reach infinite speed. In the real world, the speed of the sensors and the speed of the computer and accelleration rate of the conveyor would determine just how quickly the wheelspeed increased. But given a conveyor capable of "keeping up" the quicker the sensor and computer cylce the quicker the accelleration rate of the wheels and conveyor. Yet, STILL the aircraft WILL move forward until the point at which the tires disintigrate. So given tires, wheels and wheelbearing capable of an infinite speed, the aircraft would still take off.

A "reality" perspective on this theoretical problem.
1. If "speed of the plane" is taken to be the speed of the wheels on top of the conveyor, like a jogger on a treadmill, then you have just shown that as soon as wheel speed exceeds max tire speed, we no longer have rolling friction but more likely have "sliding/dragging friction", probably degrading into near static friction as parts fly. Therefore the plane would not take off.

2. If "speed of the plane" is taken to be relative to the ground, then because wheel speed will be twice the speed of the plane, as long as Vr*2 < max tire speed the plane will be able to take off. Otherwise, we again get into tire breakdown followed by increasing friction significantly slowing the plane down until it no longer can take off.

If the plane is prop driven, then a prop strike could become highly likely if the tires fly apart, thereby reducing the chance of take off. Certainly it would not be a good thing for a jet to lose ALL wheels either and you could envisions a lot of bad outcomes as a result that would likely prevent a successful takeoff.

Therefore, only if speed of the plane is taken to be relative to the ground and Vr*2< max tire speed do you have a "normal" take off.

egnorant
QUOTE (biplanepilot+Mar 14 2006, 05:47 PM)
MCHAT,

The wheel speed is the same as the conveyor speed as long as the two are in contact with each other. The whole key is airspeed. The speed of the air over the wings.

The wheel speed theory measures the speed of the belt as it relates to the ground.
Yet it measures the plane speed (via the wheels) as it relates to the belt.
See my recent post to show how this is impossible as applied to the original question.

Wiser people have the belt speed and the plane speed as it relates to the ground
(and the calm air) as a starting point.
Plane goes X in one direction..belt move X in the other direction...wheels spin at 2X. This was decided a long time ago.
No doubt....It flies!
The rest is a bunch of us teasing the silly people!
Bruce
krreagan
QUOTE (biplanepilot+Mar 14 2006, 10:47 AM)
MCHAT,

The wheel speed is the same as the conveyor speed as long as the two are in contact with each other.  The whole key is airspeed. The speed of the air over the wings.

I disagree, you need to factor in the forwad motion of the plane relative to the ground that the belt itself is sitting on. You are measuring the wheel speed with a speedometer, so if the plane has any forward motion at all, then the wheel speed and belt speed can never be moving at the same speed at the same time. This is the paradox/infinity of the problem when you interpret the speed of the plane as the wheel speed. And therefore, you have to measure the speed of the plane as the speed through the air (or over the ground) and not relative to the belt (wheel speed).

Krreagan
egnorant
QUOTE (Guest+Mar 14 2006, 06:06 PM)
Therefore, only if speed of the plane is taken to be relative to the ground and Vr*2< max tire speed do you have a "normal" take off.

I love that everyone is questioning the mechanical capabilities of the plane without
questioning the mechanical capabilities of the treadmill!!!
If we assume that one is incapable then we must be able to assume that both are incapable of performing the feats we apply.
Or we must assume that both are capable!!!
Assigning lesser capability to the plane is just a trick applied unfairly by those who
have no real basis for their "no fly" theories.
The "will fly" folks would never stoop to such irrelevancies!!
Bruce
Fynlcut
If we talk wheel speed and we know the speeds must always match, then the conveyor will simply move forward at the speed of the plane.
But you say the conveyor moves in the opposite direction. True in the opposite direction with a negative speed. (two negatives make a positive)
egnorant
QUOTE (Fynlcut+Mar 14 2006, 07:08 PM)
If we talk wheel speed and we know the speeds must always match, then the conveyor will simply move forward at the speed of the plane.
But you say the conveyor moves in the opposite direction. True in the opposite direction with a negative speed. (two negatives make a positive)

So the plane would be moving in one direction at a negative speed...
the belt would be moving in the opposite direction at a negative speed...

Now if we had a really big bungee cord....and a DeLorean...
Would the belt need to sink into the ground as the plane gained altitude?
If we throw a football over the belt from side to side, what is the vector change?
Would we need to lead the plane in order to hit the plane with this football?
If an asteroid breaks in half and one half hits your car, does insurance only cover for half?

I still have a lot of boring days left to kill?
Bruce

MChat
QUOTE (egnorant+Mar 14 2006, 05:58 PM)
Even in this hypothetical world the belt could not match the wheel speed.
Question says it matches exactly!
The infinite speed scenario is NOT matching exactly..it is merely trying to catch up.
Wheel speed theory as applied to this question is only correct at the 0 speed.
Any movement by the plane to achieve wheel speed will instantly develop an environment where matching speed is impossible. ((X)+y) does not=(X)....
Use any figures you want! As long as y represents the movement of the plane to achieve wheel speed. Remember that y=0 indicates no wheel speed, so X must be 0 also.
It flies
Bruce

I think we're on the same page.

I program computers for a living so I tend to think on how I would design a system that would attempt to match the conveyor's speed to the wheelspeed of the aircraft. The reality is no system could be designed no matter the technological advances, at best we have a conveyor that is "one step behind" and never truely equal to the wheelspeed of the airplane.

Obviously the question as originally stated implied the conveyor matches the actual speed of the airplane relative to the ground. Which is a simple problem once one understands what is happening. In fact even a normal passenger car will be able to accellerate on a conveyor which matches it's ground speed; only it's topspeed (relative to the ground) will be reduced by half.
Physics Student
Has anyone said anything about the fact that any force put on the wheels is turned into torque (assuming the wheel is frictionless)? taking the cross product of the force and velocity would mean the force would be applied towards the axle (meaning perpendicular to the force of the enggines). Perpendicular forces do not act on each other.

So, the plane would move forward, gain airspeed and take off, no matter if the conveyor belt was moving a billion fps
MChat
I don't know if this has been posted here yet (I didn't read through all 312+ pages) but here is a video that proves that the conveyor DOES NOT force the aircraft to remain at zero velocity:

http://videos.streetfire.net/comment/0/35E...6BA1A43A06B.htm
Guest
QUOTE (egnorant+Mar 14 2006, 06:27 PM)
QUOTE (Guest+Mar 14 2006, 06:06 PM)
Therefore, only if speed of the plane is taken to be relative to the ground and Vr*2< max tire speed do you have a "normal" take off.

I love that everyone is questioning the mechanical capabilities of the plane without
questioning the mechanical capabilities of the treadmill!!!
If we assume that one is incapable then we must be able to assume that both are incapable of performing the feats we apply.
Or we must assume that both are capable!!!
Assigning lesser capability to the plane is just a trick applied unfairly by those who
have no real basis for their "no fly" theories.
The "will fly" folks would never stoop to such irrelevancies!!
Bruce

No one can say what the characteristics of the conveyor are other than it can always match the speed of the plane. I indicated that speed of the plane could be interpreted in two ways. However, max tire speed is as real to any wheeled aircraft as Vr and obviously more important to aircraft that land and take off at high velocities. I didn't express bias as to fly/not fly as both were possible but conditionally.

You seem rather entrenched on the issue of matching wheel speeds by the way. Don't you think that matching within a millimeter/s or so would be close enough to at least consider as a possibility? If so, then case 1 that I expressed is easily an outcome.
krreagan
QUOTE (Guest+Mar 14 2006, 06:54 PM)
QUOTE (egnorant+Mar 14 2006, 06:27 PM)
QUOTE (Guest+Mar 14 2006, 06:06 PM)
Therefore, only if speed of the plane is taken to be relative to the ground and Vr*2< max tire speed do you have a "normal" take off.

I love that everyone is questioning the mechanical capabilities of the plane without
questioning the mechanical capabilities of the treadmill!!!
If we assume that one is incapable then we must be able to assume that both are incapable of performing the feats we apply.
Or we must assume that both are capable!!!
Assigning lesser capability to the plane is just a trick applied unfairly by those who
have no real basis for their "no fly" theories.
The "will fly" folks would never stoop to such irrelevancies!!
Bruce

No one can say what the characteristics of the conveyor are other than it can always match the speed of the plane. I indicated that speed of the plane could be interpreted in two ways. However, max tire speed is as real to any wheeled aircraft as Vr and obviously more important to aircraft that land and take off at high velocities. I didn't express bias as to fly/not fly as both were possible but conditionally.

You seem rather entrenched on the issue of matching wheel speeds by the way. Don't you think that matching within a millimeter/s or so would be close enough to at least consider as a possibility? If so, then case 1 that I expressed is easily an outcome.

When considering the speed of the wheels (illogical)...

The belt can never get closer in speed to the wheels then then the velocity of the plane relative to the ground...

The wheel speed (X) is the speed of the plane over the ground (Y) - the speed of the belt (Z) in the opposite direction (and therefore a negative quantity) to the motion of the plane, which imposes additional velocity to the wheels.

so the speed of the wheels is: X = Y - Z

but the question imposes the following condition on the problem:
X = -Z

Therefore we can substitute -X into the original equation for Z and arrive at:
X = Y - (-X)

So, for any forward velocity of the plane Y the equation cannot be correct and we have our paradox.

Now in real life there is always some lag in the control system so that |Z| < |X| at any time that X is increasing.

So there is no situation that can conforms to the original question posed if you interpret the "speed of the plane" as the speed of the wheels as indicated by a speedometer and the belts speed is in relation to the ground/surroundings/air.

Krreagan
egnorant
QUOTE (Guest+Mar 15 2006, 01:54 AM)
No one can say what the characteristics of the conveyor are other than it can always match the speed of the plane. I indicated that speed of the plane could be interpreted in two ways. However, max tire speed is as real to any wheeled aircraft as Vr and obviously more important to aircraft that land and take off at high velocities. I didn't express bias as to fly/not fly as both were possible but conditionally.

You seem rather entrenched on the issue of matching wheel speeds by the way. Don't you think that matching within a millimeter/s or so would be close enough to at least consider as a possibility? If so, then case 1 that I expressed is easily an outcome.

Sorry for the hard *** attitude, but we have had a rather obnoxious fellow that
used diversions similar to yours to be a pain.
You should really go back a few dozen pages and see the tangents we traveled.
I finally asked my 0 wheel speed question of him and he has not answered.
There was even thought that he came back with a new name or as a guest.

While we (my niece is helping) have found no fault with your stepped version,
we really haven't reached the point where we have convinced each other that it has no fault.
By looking at your figures (accepted as correct) is when we started questioning
mechanical capabilities of BOTH the plane and the treadmill.

Entrenched?? Yes, had to stay focused or some yahoo would try to divert and
attempt to confuse the issue. A simple proof to disprove the "no fly" guys pet theory and a challenge to them to disprove it.

As far as considering "close enough" scenarios the answer from my niece was a resounding "NO!!! not as applied to this question!!!"
I agree with her!
Consideration as a separate question is acceptable.
But, if you can have a treadmill capable of 233,411 mph then we must consider
the possibility of wheels that are capable of 233,411 mph.
Bruce

egnorant
QUOTE (krreagan+Mar 15 2006, 04:16 AM)
When considering the speed of the wheels (illogical)...

The belt can never get closer in speed to the wheels then then the velocity of the plane relative to the ground...

The wheel speed (X) is the speed of the plane over the ground (Y) - the speed of the belt (Z) in the opposite direction (and therefore a negative quantity) to the motion of the plane, which imposes additional velocity to the wheels.

so the speed of the wheels is: X = Y - Z

but the question imposes the following condition on the problem:
X = -Z

Therefore we can substitute -X into the original equation for Z and arrive at:
X = Y - (-X)

So, for any forward velocity of the plane Y the equation cannot be correct and we have our paradox.

Now in real life there is always some lag in the control system so that |Z| < |X| at any time that X is increasing.

So there is no situation that can conforms to the original question posed if you interpret the "speed of the plane" as the speed of the wheels as indicated by a speedometer and the belts speed is in relation to the ground/surroundings/air.

Krreagan

Exactly!
But it does balance when all are zero.
That is the only time.
My niece read your post and was delighted that someone else understands.
She says you get a hug!!
She almost got in trouble because it is actually an hour past her bedtime and suddenly she screams "Hell yeah!!!" at the computer.
Bruce
krreagan
QUOTE (egnorant+Mar 14 2006, 10:17 PM)
QUOTE (krreagan+Mar 15 2006, 04:16 AM)
When considering the speed of the wheels (illogical)...

The belt can never get closer in speed to the wheels then then the velocity of the plane relative to the ground...

The wheel speed (X) is the speed of the plane over the ground (Y) - the speed of the belt (Z) in the opposite direction (and therefore a negative quantity) to the motion of the plane, which imposes additional velocity to the wheels.

so the speed of the wheels is:  X = Y - Z

but the question imposes the following condition on the problem:
X = -Z

Therefore we can substitute -X into the original equation for Z and arrive at:
X = Y - (-X)

So, for any forward velocity of the plane Y the equation cannot be correct and we have our paradox.

Now in real life there is always some lag in the control system so that |Z| < |X| at any time that X is increasing.

So there is no situation that can conforms to the original question posed if you interpret the "speed of the plane" as the speed of the wheels as indicated by a speedometer and the belts speed is in relation to the ground/surroundings/air.

Krreagan

Exactly!
But it does balance when all are zero.
That is the only time.
My niece read your post and was delighted that someone else understands.
She says you get a hug!!
She almost got in trouble because it is actually an hour past her bedtime and suddenly she screams "Hell yeah!!!" at the computer.
Bruce

Ahhh shucks!

Krreagan

Fynlcut
QUOTE (egnorant+Mar 14 2006, 07:50 PM)
QUOTE (Fynlcut+Mar 14 2006, 07:08 PM)
If we talk wheel speed and we know the speeds must always match, then the conveyor will simply move forward at the speed of the plane.
But you say the conveyor moves in the opposite direction. True in the opposite direction with a negative speed. (two negatives make a positive)

So the plane would be moving in one direction at a negative speed...
the belt would be moving in the opposite direction at a negative speed...

Now if we had a really big bungee cord....and a DeLorean...
Would the belt need to sink into the ground as the plane gained altitude?
If we throw a football over the belt from side to side, what is the vector change?
Would we need to lead the plane in order to hit the plane with this football?
If an asteroid breaks in half and one half hits your car, does insurance only cover for half?

I still have a lot of boring days left to kill?
Bruce

Simply put, the wheels never turn, but the plane moves forward as the coveyor (moving at a negative speed in the opposite direction) moves in the direction of travel produced by the thrust of the engine. or something like that.
sooks
Well thats not fair that just he gets the hug.... A lot of us have been saying that for a long long time!!!!!
MChat
QUOTE (egnorant+Mar 15 2006, 04:57 AM)
While we (my niece is helping) have found no fault with your stepped version, we really haven't reached the point where we have convinced each other that it has no fault.
By looking at your figures (accepted as correct) is when we started questioning mechanical capabilities of BOTH the plane and the treadmill.

Consideration as a separate question is acceptable.
But, if you can have a treadmill capable of 233,411 mph then we must consider the possibility of wheels that are capable of 233,411 mph.

Of course both the aircraft and the conveyor would have mechanical limitations. Since the conveyor exists only for this hypothetical situation, it's limits are whatever we define them to be. However, airplanes actually exist and I think the weakest link is the tires' speed rating. Looking online the lowest speed rating I found was 120, while the highest was in the low 200's.

So for the most logical version of this problem, where the conveyor matches the aircraft's actual speed and not some attempt at matching it's wheel speed, it is certainly possible that the aircraft is equipped with suitably rated tires and will reach departure velocity before the tires disintigrate.

For the illogical (and impossible, except the "stepped" model) version of this problem, where the conveyor matches the wheelspeed of the aircraft. The tires would disintigrate within seconds after initial movement of the aircraft. However I would think that a real conveyor would reach it's mechanical limitations around the same time and would require an extremely powerful engine just to keep up with the aircraft's wheelspeed.
egnorant
QUOTE (sooks+Mar 15 2006, 02:28 PM)
Well thats not fair that just he gets the hug.... A lot of us have been saying that for a long long time!!!!!

We may have missed it as we did not arrive until page 271.
The discussion was bogged down on speed and velocity.
ATL5p had just proclaimed that his toy plane proved something.
I had just arrived announcing that it was a word problem and
krreagen nudged us to examine the impossibility of the wheel speed theory.

I'm sure you qualify for at least a hug from a 14 year old girl!
As do many who stood fast and battled against the forces of obstinance and ignorance!!
Bruce
biplanepilot
Krreagan,

I'm one of the 'it will fly guys' but I have to disagree with you about wheel speed vs conveyor speed. The conveyor is just a big wheel, and while the two are in contact (just before flight) they have to be at equal speed. Not RPM, but speed.
If two wheels are rolling in contact with each other, their speed at the contact point has to be equal or there would be a bunch of rubber burning.
All this talk of wheels coming apart at high speeds is meaningless. As soon as the average plane reaches between 40 and 80 mph (airspeed) it's airborn and you can turn that damn conveyor off.
krreagan
QUOTE (biplanepilot+Mar 15 2006, 10:28 AM)
Krreagan,

I'm one of the 'it will fly guys' but I have to disagree with you about wheel speed vs conveyor speed.  The conveyor is just a big wheel, and while the two are in contact (just before flight)  they have to be at equal speed.  Not  RPM, but speed.
If two wheels are rolling in contact with each other, their speed at the contact point has to be equal or there would be a bunch of rubber burning.
All this talk of wheels coming apart at high speeds is meaningless.  As soon as the average plane reaches between 40 and 80 mph (airspeed) it's airborn and you can turn that damn conveyor off.

Think of it this way...

Get on a treadmill with rollerblades on and stand at the far back of the belt, Now turn on the treadmill and remain where you are. The wheel speed matches that of the belt... (forward velocity equals zero) Now push/pull yourself forward to the very front of the belt while its going at a constant velocity, While you are moving from the back to the front relative to the ground, your wheels are moving at an additional speed equal to how fast you push yourself forward. So you have to add in your forward velocity relative to the ground, which is also what the treadmill is sitting on.

This is the X - (-Y) component.

When you are sitting still at the back of the treadmill, Y = 0, So the two speeds are equal. When you move forward, Y > 0 and therefore the equation becomes invalid.

By your logic, normal planes would not be able to take off because of the difference in runway/wheel speed. The runway is a belt going 0-mph and the plane is going 100-mph but there is no conflict between the surfaces (except when the wheels initially touch the runway on landing, but this is another situation).

Krreagan
MChat
QUOTE (biplanepilot+Mar 15 2006, 05:28 PM)
I'm one of the 'it will fly guys' but I have to disagree with you about wheel speed vs conveyor speed. The conveyor is just a big wheel, and while the two are in contact (just before flight) they have to be at equal speed. Not RPM, but speed.
If two wheels are rolling in contact with each other, their speed at the contact point has to be equal or there would be a bunch of rubber burning.
All this talk of wheels coming apart at high speeds is meaningless. As soon as the average plane reaches between 40 and 80 mph (airspeed) it's airborn and you can turn that damn conveyor off.

On a normal aircraft traveling at 50mph, on a normal runway, the bottom of the aircraft's tire (the part in contact with the runway) is traveling 0mph and the top of the tire is traveling 100mph; the axle in the center of the wheel is traveling (obviously the same speed as the aircraft) at 50mph. I think what most would consider "wheelspeed" is the speed at the center of the wheel, or the average between the top and bottom of the tire.

Guest
QUOTE (biplanepilot+Mar 15 2006, 05:28 PM)

All this talk of wheels coming apart at high speeds is meaningless.  As soon as the average plane reaches between 40 and 80 mph (airspeed) it's airborn and you can turn that damn conveyor off.

A 737-200 has a Vr of 131 kts. Max tire speed is about 195 kts. If the speed of the plane is taken to be relative to the ground, hence wheel speed is double the ground speed, you reach max tire speed while ground speed is only 97.5 kts, well short of Vr. You'd come closer but still fall short in a Citation CJ3 for Vr(102 kts), V1(takeoff speed=105kts) and V2 (takeoff safety speed=115 kts)

Typical GA singles might have 6 ply tires with a max ground speed rating of 120pmh, or 104 kts. You'd get to the max tire speed at 52 kts. There are many singles with Vr well above that eg, Cirrus SR22 Vr=70 kts and nearly all retracts.

So again, only when you measure the speed of the plane relative to the ground and have an aircraft with Vr*2<max tire speed would you have a "normal takeoff".
NASA Engineers
This problem can be understood quite simply by considering the example of a plane with frictionless bearings in the wheels. Examine the case when no thrust is applied and the conveyer moves at any speed. The plane will remain motionless with respect to the ground while the wheels spin at the conveyer speed. Now apply some thrust and the plane will start to move forward relative to the ground because in this case the speed of the conveyer (with frictionless bearings) can have no effect on the plane motion. As you increase thrust the plane will take off just like a normal plane. In fact from an observer on the ground the take-off will look perfectly normal. Now add some friction to the bearings and the only thing you will have to do is add a little more thrust to overcome this friction. Again from an observer on the ground the take-off looks exactly the same with the exception that the wheels seem to be spinning too fast. This is different from a car because the car must have locked (not frictionless) bearings (at least in one axel) in order to move.
sooks
unfortunately atl5p cant understand that
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