hey, flinchy here. i just discovered this forum and im a little curious about jet engines. i have a slight grasp over the principles and physics that make them work, but have any of you built one before? if you have please give me some advice on what i should and shouldn't do. any comments would be much appreciated. oh and another thing, im trying to build it for under $200US. thanks.

-Flinchy

Hi Flinchy,

In the UK we have a program called 'Scrapheap Challenge' where competitors are given a big scrapheap to play with and a challenge (I hope you didn't guess that from the title).

One challenge was to build a dragster and a team opted for a pulse jet. From memory they used a U shaped tube (no popper valves) and it worked (a bit) and propelled their car forwards. The acceleration was up to about walking speed within a few seconds. It was fairly clear that pulse jets are among the noisiest things you can get involved with.

It can be done.

Good luck,

C2.

I saw that episode. Essentially petrol is pumped into the U-tube and ignited causing a backward force and propelling the buggy forwards. This is repeated many times a second to create a large acceleration forwards (Newton's third law)

I have not made an engine like this before but wish you all the luck with this project.

The last time I checked a U-shaped tube cost less than $200. Post back how you get on or, even better, film it and post it on youtube.