Quote:
Originally Posted by MMahoney
I built a quick prototype pneumatic launcher today and was disappointed by how weak it shot. We did a variety of tests at different angles (~10 degrees, 45 degrees, and ~75-80 degrees) and found that the ball flew about 6-7 feet at highest. Barely enough to clear the truss.
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One issue with a pneumatic cylinder launcher is the peak piston velocity being restricted by the rate at which air ahead of the piston can exit the cylinder.
Ideally, the space in front of the piston disk seal would be a vacuum, and offer no resistance. This could be accomplished by sealing both ports of the cylinder with the piston extended.
Then by mechanically pulling the piston back into the cylinder so as to build up pressure on one end and partial vacuum on the other piston exit end, you can make it into a "gas spring"
Releasing the hold on the compressed piston would fire it at a higher speed than when there is air ahead of the piston.
This may not be legal though. There are many safety issues. Too much piston retraction could build up pressure in the cylinder exceeding its limits.
Also, piston can overshoot inside cylinder and impact the head at the exit end, damaging it.
-Dick Ledford