Larger bore actuation speed

[couvillion]

Something like this

I've tended to think that something shape like this gives the most amount of force to start the system moving.

[hrench]

Team 1108 has been doing pneumatic catapults for years with some winning designs.

We design so the cylinder isn't fully retracted so there is a 'chamber' in the back half. Something like 4-inches for a 12 inch stroke. We fill the cylinder with any-old slow valve while we're holding it down with an electro magnet holding a puck of steel on the catapult. Let go of the magnet and it flys!

Here's the magnet we're using this year...5.6 watts/ http://www.mcmaster.com/#5698k116/=118b3ox

[ollien]

Originally Posted by couvillion

Something like this

I've tended to think that something shape like this gives the most amount of force to start the system moving.

So I would use the cam to push the piston arm out slightly?

Originally Posted by hrench

Team 1108 has been doing pneumatic catapults for years with some winning designs.

We design so the cylinder isn't fully retracted so there is a 'chamber' in the back half. Something like 4-inches for a 12 inch stroke. We fill the cylinder with any-old slow valve while we're holding it down with an electro magnet holding a puck of steel on the catapult. Let go of the magnet and it flys!

Here's the magnet we're using this year...5.6 watts/ http://www.mcmaster.com/#5698k116/=118b3ox

Wow this is neat but I'm not sure how well we'd be able to mount it given our current setup. I will be sure to look into this though. Thank you! Do you have any pictures of how you've mounted this on your bot?

[hrench]

Originally Posted by ollien

Do you have any pictures of how you've mounted this on your bot?

I don't have any straight-on pic available right now, but I think you can see it in this one okay. The cylinders are on the top and the magnet is at the left, under the hoop of the gray PVC catapult. And yes, just PVC pipe has worked great for us. Least expensive material in the world, but the flex it has actually makes longer shots than an aluminum catapult.



https://www.facebook.com/130742220315492/photos/ms.c.eJxFyssJACAQA9GOJNmPZvtvTEXF2~;AYYpinkJ3pqmq8 4BVaFQ~_Iczwo44Yh~;2AyRGIC0oYQ9A~-~-.bps.a.1072296029493435.1073741901.130742220315492/1072359212820450/?type=3&theater

[ollien]

Originally Posted by hrench

I don't have any straight-on pic available right now, but I think you can see it in this one okay. The cylinders are on the top and the magnet is at the left, under the hoop of the gray PVC catapult. And yes, just PVC pipe has worked great for us. Least expensive material in the world, but the flex it has actually makes longer shots than an aluminum catapult.



https://www.facebook.com/130742220315492/photos/ms.c.eJxFyssJACAQA9GOJNmPZvtvTEXF2~;AYYpinkJ3pqmq8 4BVaFQ~_Iczwo44Yh~;2AyRGIC0oYQ9A~-~-.bps.a.1072296029493435.1073741901.130742220315492/1072359212820450/?type=3&theater

I must be missing something here. Under that gray PVC loop I see a bunch of air tanks but I don't see a magnet anywhere, nor do I see any pistons that go into the PVC. Could you point me to where I should look at this? Sorry! I hate to bother you with this.

Originally Posted by couvillion

Yes

I'll see how I can utilize this tomorrow... Hopefully I'm able to fit something in there. Thanks!

[couvillion]

Originally Posted by ollien

So I would use the cam to push the piston arm out slightly?

Yes