 ARS rockets |
 G.Edward Pendray, Mrs Pendray and Hugh F. Pierce preparing the ARS-1 rocket. |
History:
- On April, 4 1930, a dozen space enthusiasts gathered in New York to create the American interplanetary Society (AIS), modeled after the rocket societies of Europe, present by G. Edward Pendray, David Lasser, and others. Vice President Edward Pendray was charged with creating a rocket research program. While the group knew of Robert Goddard′s work with solid propellant rocketry, and known that Goddard had not yet flown liquid propellant rockets.
- When Pendray had the opportunity to vacation in Europe in 1931, he took advantage of the trip to meet with the only group known to be working on liquid fuels, Germany′s Verein fur Raumschiffahrt (Society for Space Travel, abbreviated VfR). Pendray was warmly welcomed by the group. He was shown around the Raketentlugplatz at a time when the VfR were building their MIRAK-1 rocket, and testing suitable liquid propellant engines for it. When Mr Pendray retumed to the United States, he was obviously influenced by what the Germans had shown him, and brought back detailed sketches of the VfR′s Mirak rockets. The similarities between MIRAK and early ARS rockets is very apparent. While the ARS-4 rocket is very similar to the later REPULSOR designs.
- The ARS soon set to work duplicating the German efforts, and in November 12, 1932, ARS rocket No. 1 emerged
from a member′s basement machine shop.
The ARS-1 rocket was 2.11m (6’11") long and was 0.21m (8.3") wide. Empty weight was 6.8 kg. A 27 kg thrust liquid propellant engine of aluminium/molybdenum alloy, was situated in a water cooling aluminium jacket in the nose region. The engine was 0.15m (6") long and 0.075m (3") in diameter. Two 0.04m (1.5") diameter cylindrical tanks, each 1.6m (5'6") long, held gasoline (petrol), and the other Liquid Oxygen (LOX). Pressurisation was by compressed Nitrogen. The rocket borrowed the VfR′s 2-stick Repulsor design, with four aluminium stabilising tins situated at the rear. The rocket was completed in January 1932, but finding a suitable firing site was more dificult than expected. Eventually they arranged to use a tield at a New Jersey farm, near Stockton.
The site was prepared from August 1932. The launch site consisted of two dugout trenches; one for close observation of the test, the other for control of the rocket. A two pole gantry was set up. This was 4.27m (14 feet) high, and almost 3.66m (12 feet) wide at the base. lt consisted of rounded wooden poles, supported by planking. This was to guide the rocket upwards should it break free during static testing.
The first static test took place successfully on 12th November 1932. Relating the event a short while afterwards, Mr Pendray said; "Dr. Lemkin lit the torch, which Mr Lasser canied out to the rocket, igniting the fuse. For an instant there was a great flare, as the pure oxygen struck the buming fuse. In an instant the petrol was also pouring into the rocket. The fuse, the flare and the uncertainty about tl1e performance of our rocket engine all disappeared at once, as with a furious hissing roar, a bluish-white sword of flame shot from the nozzle of the combustion chamber, and the rocket lunged upward against the retaining spring. It is impossible adequately to describe that sight, or to convey the feeling it gave us. We forgot to remain behind the shelter of our earthworks. Moreover we forgot to count the sewnds asthey passed in that downward pouring cascade of tire..." The rocket produced 27 kg (60 pounds) of thrust for 20-30 seconds, in which parallel oxygen and fuel tanks trailed behind the motor. After a static test on a New Jersey farm, the fragile machine was damaged in the test and not subsequently flown. The club decided to rebuild it into an improved, more robust rocket, ARS No. 2.
Credit: Peter Alway
The design of the engine of ARS-2
- Work on the ARS-2 rocket began shortly after the ARS-1 test bum. It used a number of components from the previous rocket.
ARS No. 2 featured a 3" (76 mm) diameter by 6" (152 mm) long engine in aluminium, mounted between two aluminum tubes
containing liquid oxygen and gasoline. A small hole in the tip of the nose cone permitted air-cooling of the engine. The
oxygen tank was pressurized by gaseous oxygen boil-off, while pressurized nitrogen forced gasoline into the engine.
The propellant tanks were placed closer together. The valves were improved, and a new nose cone with air coolant inlet was built.
The aluminium tins at the rear were replaced with smaller balsa wood fins.
Aluminum paint protected the fins from the blast of the rocket exhausts.
A gantry, designed by Laurence Manning, was made of two 0.05m (2“) pine poles, 4.6m (15 feet) long, supported by 0.1 x 0.1m (4" x 4") timber around the base, and with wooden supports further up. It was tilted 5 degrees from the vertical on the launch site, at Great Kills, Staten Island beach, New York. This ensured that the rocket would splash down safely out in the bay, where it could be recovered. - On May l4, 1933 ARS experimenters, accompanied by two newsreel camera crews, carried their rocket to Great Kills, Staten Island beach for its first test
flight.
After a brief static firing, the rocket was refilled with liquid oxygen and gasoline. Three minutes before launch, a fuse was lit under the nozzle. At the appointed moment of launch, an ARS member, sheltered in a dugout, pulled a cord leading to the propellant valves. The valve handle fell off. Another member ran from the dugout and re-attached the handle. Before he could return to the dugout, the valve man pulled the cord, and the rocket lifted off.
ARS-2 was launched at 11.20am on 14th May 1933. Once it cleared the 15-foot (5 m) launch rail, ARS No.2 tumed into the wind, 90° from the planned seaward trajectory. The rocket was expected to bum for 20 to 30 seconds, (as had ARS-1) and reach an altitude of about a mile (1.6 km). But when the rocket reached 250 feet(75 m), the oxygen tank ruptured with a loud pop. Due to the design change of placing the propellant tanks closer together, the heat from the exhaust caused the LOX tank to burst. The rocket broke up, and the engine and tank remains splashed into the water at about 122m (133 yards) range, where they wererecovered. - The name was changed from AIS to ARS (American Rocket Society) on 6th April 1934 to emphasise the aims of the Society.
Membership soon grew, and experiments were done with commercially available firework rocket motors.
ARS-3 rocket being preparing for static test in September 1934.
ARS-3 was designed, in 1933, by Alfred Africano, G. Edward Pendray and Bemard Smith. lt was about 1.68m (5‘ 6”) long and 0.2m (8”) in diameter. At launch it weighed 9.07 kg, and the rocket engine produced 27.2 kg thrust Propellants were stored in tanks in the cylindrical head, mounted above a stabilising device, also cylindrical. 1.125 litres (quarter gallon) of gasoline, and 4.5 litres (1 gallon) of Liquid Oxygen were used. The rocket did not fly, but underwent several static tests on Staten Island, in September 1934, in a new steel gantry.
- The fourth liquid rocket was launched on September 9, 1934 from Marine Park, Staten Island, New York.
ARS-4, at first sight, closely resembled a German REPULSOR-3 or -4 rocket It was 2.29m (7'6") long, 0.075m (3") in diameter,
and had its liquid propellant engine at the top. The propellant tanks were dragged up by their feed lines in the manner of a "one
stick Repulsor“.
The engine was located on top of the gasoline tank, above the string operated valves. lt had four slightly canted, splayed, nozzles. The liquid oxygen tank was located at the rear, as far from the exhaust heat as possible with this design. Propellants were 0.56 litres (1 pint) of gasoline, and 1.13 litres (2 pints) of LOX. The designers were Cart Ahrens, Alfred H. Best, Laurence Manning and project leader John Shesta. First ARS~4 static test took place on 10th July 1934 at Staten Island. The test ended in an engine burn-through. - The rocket was repaired and modified during July and August 1934. A 'rotatingvane' head was located above the engine, to lower the rocket, spinning, at low descent rate. This was designed to reduce impact damage and to take up less spaoe than a parachute. The vanes deployed at low speed near apogee, due to lower air pressure on them.
- First flight was on 9th September 1934 at Great Kills, Staten Island. It used the new steel gantry. The engine bumed for about 15 seconds, during which time the rocket reached an estimated 268 to 313m/s (600 - 700 mph). Maximum altitude reached was 116m (382 ft), and the impact range was 408m (446 yards). The only disappointment was the failure of the recovery device to operate. It flew 407 meters downrange, landing in the New York Bay.
- ARS-5 never reached the hardware stage, although several of the component designs were used on other rockets. It used a novel cone-engine, at the head, without constriction. Also, both propellants, gasoline and liquid oxygen, were to be stored in the same tank, being separated by a movable piston.
- H.F. Pierce of the American rocket Society launched a liquid fueled rocket to about 250 feet (76 meters) on May 9, 1937. The launch took place from Old Ferris Point, the Bronx, New York (Gatland 1989, p. 11). On December 10, 1938, the American Rocket Society tested a 90 pound (41 kg) thrust regeneratively cooled liquid rocket motor designed by James H. Wyld.
- Then the society turned to creating improved engines and giving them static tests, often
going to great lengths to avoid suspicious police and tire officials. With the onset WW II, the club gave up on
experimentation and evolved into a professional society, producing a trade journal, and eventually becoming today′s
American Institute of Aeronautics and Astronautics.
Four members of the pre-war group went on to form Reaction Motors, Incogpgmted. After the war, Reaction Motors produced the powerplants for the X-l, X-15, MX-774, and Viking sounding rocket. While the ARS No. 2 was not a great accomplishment, the ARS program proved to be a valuable training ground for the nation′s rocket engineers.