new member. my first air motor.

[MCRIPPPer]

hey there. im an 18yo "kid"* (*unfortunately not technically )

last year i got a mini mill and made lots of things. a few weeks ago, i made this little air powered engine out of random pieces i had around. i revised it several times, mostly improving the valve system. this was done completely on my mill and with files and dremel. (although 2 days ago i got a 7x12 hitorque lathe, it was not used to build this engine.) here are some pics of the engine. sorry the pix are a little bit blurry because my camera self focuses (very poorly at close distances, no matter how i set it up).









here is the simple valve. it was a mini walbro carburetor shaft from a chainsaw. it rotates side to side and exposes the intake or exhaust port. the thrust bearing ball and retainer keep the valve from being blown out the top from the air pressure.


what should my next engine be? i want to do a 4 stroke air motor because they sound pretty cool. i don't really understand how the valve system on them works tho.


i will try to get a video too. i also added a throttle valve and tried to balance the flywheel a little bit after the time these pictures were taken.

 

[MCRIPPPer]

here is a short video of it running. i dont know why the lighting looks so weird.

http://www.youtube.com/watch?v=EaOs_mVna0Y&feature=youtu.be

 

[jwcnc1911]

Verry nice, love it! Ps.: you can always use a drill chuck to turn small parts in your mill!

 

[MCRIPPPer]

thanks. that is exactly how i did it. i made a little lathe bit by drilling a 1/8 in hole in a square of aluminum, and used red locktite to hold a 1/8" piece if hard steel in. i sharpened it up and clamped it in my vice. to hold the parts i drilled a 1/8 inch hole, and used red locktite again to "glue in" a rod to hold in the drill chuck. it turned out pretty good for not having a lathe. the current valve rod you see in the pictures is very low drag and so it runs very slow. i made a low pressure tester out of drinking straws filled with water. it would idle at between 12 and 15 inches of water. (still have not calculated psi from that) but i can blow into it and it will run fine. my valve system used to be a spring loaded guitar string that would be hit by a pin in the flywheel. it rand good and was very interesting, but would not run very slow. it was kinda cool because the engine would literally "bounce" of the rev limiter because the guitar spring would eventually not be able to keep up with the rpm and start to bounce, making a very high speed hit and mis like acton.

 

[Philjoe5]

Nice work. Congratulations on your first (but not last) engine.

If you really want to learn how an engine works, make one.

All it takes is some patience, a few good tools, Oh, and did I mention patience?

Cheers,
Phil

I was 60 when I made my first "air motor". You've got at least 42 years to refine your technique. Have fun

 

[MCRIPPPer]

i see all these 4 stroke compressed air engines. do they just leave the exhaust open for most of the time? how do those little ball/spring valves work? they dont seem to be one way valves.... somehow they work the intake and exhaust it seems...

i guess "regular" 4 stroke engine type valves could also be used.

 

[thayer]

Very nicely done! Look forward to seeing your next effort.

Thayer

 

[MCRIPPPer]

thanks guys. any suggestions on what type of engine to build next? i want one that will sound cool (horsepower is not a very large concern on a model engine that is just supposed to be "cool" )