Fri Sep 15, 2006 6:08 am
The basic idea on the second rocket is that is fits the barrel, not airtight, but almost airtight. Behind the rocket, the orange thing, is an airtight cilinder. I thougt of a wooden one, or something lighter, possibly with O-rings. This is only used to push the rocket out. Since you have to make it, it would be a shame to make one for every launch, zo i attached a chute on the back. The idea is that the chute and the cilinder get shot out of the barrel, pushing the rocket forward. Once in midair, the chute opens and stops the cilinder. The main idea is that it falls to the ground at max 10 meters from the barrel, so you dont have to go and look for it. The rocket is on it's way then.
The first drawing has a rocket with side fins. They don't fit airtight in a barrel, without damaging the fins, and even then. So the rocket is smaler than the barrel, so the fins can stand up like they used to. There for the cilinder used here needs a hole in it, so the back cone of the rocket (to make it airodynamic) fitsd in it, and the cilinder keeps the rocket centered in the barrel. The yellow things on the front of the rocket is hard foam or something light. It is shaped, zo is fits on the rocket, keeping the nose cone in the center of the barrel. Notice the chaped angle in front. It is shaped that way, so when the rocket leaves the barrel, the air gript between the foam and the nose cone, pushing the foam awai from the rocket, giving it a free flight. The foam is attached to the cilinder in the back by thin wooden sticks. They need to be fastened at the cilinder such way, that they can turn, i mean, like a door that opens. The coppeling between the cilinder and the sticks should be some kond of turning point.
When the rocket leaves the barrel at lets say 80 mph, the air pushes the foamparts away from the rocket, at that time the chute opens, and works as a break on the cilinder. The rocket keeps flying it's speed, and leaves the cilinder. The foam, stil having some forward speed, will stay open long enough to give the rocket time to leave and continue it's flight.
So, that's the main idea. In theory it should work well. When i have my first spud gun, i start working on the rockets.
The stabiliser of the second missile is made out of pvc as wel. The tailstick is made out of pvc al wel, out wood. Should indeed be strong enough to push the head of the rocket out of the barrel without breaking