American Rocket Society: Engines and Parts
49. Static test of liquid-fuel rocket engine on American Rocket Society Test Stand No. 2.
50. Two early types of liquid-fuel, rocket motors. Left, the original ARS motor; right, a four-nozzle motor for ARS No. 4 rocket.
Thrust stud for fastening to rocket Blast chamber Fuel feed Oxygen feed Nozzle Water jacket Nozzles Thrust and fuel column attached to rocket Fuel feed Oxygen feed
The American Rocket Society (ARS) was the first organization in the United States dedicated to rocket research. The society was founded in New York City in March 1930 by G. E. Pendray and David Laser. The first successful ARS rocket was launched on May 13, 1933. The group continued to build and test rocket engines until the outbreak of World War II. After 1945, the ARS became a professional society for engineers involved in astronautics. The ARS joined with other aeronautical engineering groups to form the American Institute of Aeronautics and Astronautics in 1963.
The first liquid-propellant rocket engines built by the American Rocket Society were machined from blanks of heat-resistant, cast-aluminum alloy. Engine No. 1 powered the first two rockets designed and constructed by the ARS. It featured combustion chamber walls 12.7 millimeters (½ inch) thick and burned liquid oxygen and gasoline to produce a thrust of 27.22 kilograms (60 pounds). Liquid oxygen was pressurized by partial evaporation, while bottled nitrogen forced gasoline from the tank to the engine.
ARS Engine No. 4, like its predecessors, was mounted in the nose, rather than the tail, of the rocket. The engine featured a single combustion chamber and four nozzles. The nozzles directed the jet gases to the rear and slightly away from the top of the gasoline tank on which the engine was mounted. The rocket powered by this engine was tested on September 9, 1934. It rose several hundred feet, at which point one of the nozzles burned out, bringing the flight to a close. In 1938, ARS member James Wyld suggested a cooling system whereby propellants circulate through a jacket surrounding the combustion chamber. Engines using this system are termed “regeneratively cooled.” The first Wyld rocket motor tested developed 41 kilograms (90 pounds) of thrust for 13½ seconds. It proved so successful that Wyld and other members of the ARS founded Reaction Motors, Inc., to produce and sell rocket engines based on this design.
The performance of motors developed by the ARS prior to World War II was measured on a test stand with built-in fuel and oxidizer tanks and bottled nitrogen gas. The engine was mounted on a carriage, and connected to the stand’s propellant tanks by flexible metal hoses. Thrust was indicated on a pressure gauge. The stand was first used in 1938.
All American Rocket Society artifacts are from G. E. Pendray and the American Institute of Aeronautics and Astronautics.