5236 Piston Catapult
 

This catpult is in the early stages, as we are an inexperienced rookie team, so we are looking for any suggestions you may be able to provide.
We are currently working on making it shorter, as it does not currently fit size requirements, but the viedo is helpful in showing our progression.
The cylinders we are using are 1.5in bore, but I'm not sure on the stroke.
Only the last shot is using the selenoids, all the others use the straight air compressor. All previous shots with the air compressor were at 60psi.

http://www.youtube.com/watch?v=r-9v9loC2As

Re: 5236 Piston Catapult
 

Looks pretty good to me! I would continue to play with the position of your cylinders' attachment points to find a sweet spot for throwing. Be sure to test over and over again, and continue using the solenoid to mimic the robot as much as possible. If it were me, I would try rigging up some storage tanks and regulators to see how much air you are using with the components that will be on the robot and then you can get a real idea of performance as you start to scale down your launcher. That first shot looked a lot like ours!

Re: 5236 Piston Catapult
 

Good job. if you want to get more out of it remember that all cylinders retract with less force then they extend with due to the rod taking up part of the area the air pushes on to retract, while extending it has full force

Re: 5236 Piston Catapult
 

I almost pointed this out but it looks like they switched it in that last shot

Re: 5236 Piston Catapult
 

That was the only video we had of that configuration, but we did fire from the same side of the axle as the ball. It did work better, but now we have to deal with the angle of attack for the pistons.

Re: 5236 Piston Catapult
 

Make sure you calculate how much air you're using every time you fire that, and verify that your reservoirs will have enough for however many shots you intend to make. Otherwise keep up the good work, it looks like a solid design that should serve you well.

Re: 5236 Piston Catapult
 

Great job! It works :D.

This is why I like rookie teams. They can do BIG things from the SMALL number of resources available to them when starting up!

Kudos to you and keep up the work ;)