[Illustration: 49. Static test of liquid-fuel rocket engine on
American Rocket Society Test Stand No. 2.]
[Illustration: 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.