Piston launchers were developed in the 1970’s as competition rocketeers tried to increase performance. The piston launcher uses the exhaust of the rocket, that usually spills into open air, to build up pressure in the piston propeling both the rocket and piston forward.Howard Kuhn created the design most often used today in piston launchers. They eliminate the need for launch lugs and thus reduce the drag on the rocket. They also increase the initial velocity of the rocket propelling into greater altitudes. Are any of you out there using piston launchers? If you are interested you may want to check out the following links.
Heavenly Hobbies has Piston Launchers for Sale