V.A.L Piston Valved Antenna-Golfball-Nerf Launcher (video)

[MrCrowley]

It coated with a wood wax which also doubles as a lubricant. It's 100% waterproof

[Mitchza89]

Oh very nice. I'll have to get myself some of that

[MrCrowley]

Yeah and the best part is it soaks into the wood with very minimal expansion.

[mysticjbyrd]

On the gif image,
http://i75.photobucket.com/albums/i290/ ... on5fps.gif

you showed a ball on spring that lets air into the tank. But I cant see anything about making that inside of the piston in the instructions.

How is the piston allowing air to fill the tank w.o the ball valve?

[jackssmirkingrevenge]

On the gif image you showed a ball on spring that lets air into the tank. But I cant see anything about making that inside of the piston in the instructions.

Unless your piston is 100% airtight such a valve is unnecessary, and most pistons aren't.

[mysticjbyrd]

I am looking to build an air cannon for a school project. Accuracy between 20 and 50 yards is key.

Would you expect to get better accuracy out of a piston or some other type of valve? If so what type of valve would you recommend?


PS: I can only used compressed air.

[jackssmirkingrevenge]

What would you define as "accuracy"? What size of target do you expect to be able to hit consistently?

There is some discussion on the parameters necessary for an accurate launcher here which you might want to read through.

[mysticjbyrd]

There will be 3 targets laying flat on the ground at anywhere between 20 and 50 meters away. The class will be separated into groups and the team with the most accurate setup, most points, wins.

0 - 2.5 ft is the inner radius of the target (Bullseye) = 5 pts
2.5 - 5 ft is the middle radius of the target = 2 pts
5 -7.5 ft is the outer radius of the target = 1 pt


thx for link and info

[Technician1002]

Mystic, you may wish to start your own thread on the competition. This thread is for Mr C's cannon. There you could publish the full rules, list of the projectiles, pressure and material limits, etc. The team would like to help.

Edit, moved this post to the other thread to reduce the hyjack impact.

[mysticjbyrd]

Great post, Technician1002. I just wish I knew what the abbreviations meant. Still a noobie to this stuff.

Anyways I will make another post with all the rules and hopefully you and some others can come fill in the gaps for me.

Anyways, here is the link to the new post.

http://www.spudfiles.com/forums/viewtop ... tml#263222

PS: I hope this is the appropriate forum.

[Technician1002]

Post moved to the contest thread.

[Reactor4]

sweet cannon man, nice an clean! and i like your piston too, what is that reducing bushing made out of? It looks like plastic, PE maybe?

[MrCrowley]

Cheers, the black reducing bushing is made from HDPE.

[Reactor4]

okay nice im all to familiar with the PE family, i have machined soooo much of that stuff

[MrCrowley]

New video 12/02/2010:
[youtube][/youtube]