From 1939-1940 a series of rocket engine tests to support development of a JATO pod were conducted from Peenemuende-West with a He-111. It was found that liquid oxygen was not an appropriate oxidiser for civil use, so the engineers at Walther - Kiel introduced hydrogen peroxide as an alternate. The Walther engine was simpler than the rocket team's prototype, could produce 1000 kgf for 300 seconds, and was capable of taking a rocket fighter to 12 km altitude within two minutes from engine start.
Goddard began tests of two propellant pumps, called A and D. These were selected for use in four proving-stand tests (P1 to P4), from January 6 to February 28, 1939. From these tests it was concluded that a small chamber, or gas generator, producing warm oxygen gas, should be developed for operating the turbines.
Russian engineer cosmonaut 1965-1980. Graduated from Moscow Aviation Institute Soviet Air Force, liaising with aircraft industrial enterprises. Cosmonaut training November 1965 - December 1967. Worked at Gagarin Cosmonaut Training Center. Killed in an auto crash.
Engine used 29 lb liquid oxygen; 45 lb gasoline; produced 671 lb of lift for 12 sec, with jet velocity of 4820 ft/sec; oxygen 2.15 lb/sec; gasoline, 2.28 lb/sec; mixture ratio 0.94. Over 24 pump tests were completed by the time of the last run on February 28.
This was the first time he became acquainted with liquid rocket engine technology. 300 kgf and 1000 kgf engines were fired in his presence. A colour-coded cutaway model of the A3 rocket was presented and its systems explained. Hitler was quiet throughout the exhibits and asked no questions. Afterwards, while taking lunch at the mess hall, he asked only about the development schedule (clucking when told), the range of the missile, and the impact on the schedule if synthetic 'Eisenbled' was substituted for light metal alloys in the rocket frame. Hitler spoke of deceased rocket pioneer Max Valier - he had known him in Munich, but dismissed him as a dreamer. Dornberger countered by comparing the state of rocket development to the early days of the zeppelin, when Lillienthal made the first primitive experiments. Hitler in turn dismissed airships as dangerous, filled with explosive gas . The Fuehrer finally departed with handshakes and few words. His summary of the day: 'Es war doch gewaltig' (it was impressive, nevertheless). The rocket team was dismayed - it was the first time a visitor had exhibited no reaction to the power the rocket engines when fired for their benefit. But on the plus side, Von Brauchtisch said he was astounded at the progress made by the team in only a few years. Dornberger believed Hitler was enthralled with artillery and tanks, and was unimpressed with rocket technology. He thought Hitler didn't understand the possibilities and didn't believe the time had come yet for development of the rocket as a weapon.
Series P section B was a series of tests by Goddard in development of a gas generator to run turbines. Through April 28 a series of eleven static tests (Pa-k) of a new gas generator was made near the shop. The best form developed ran steadily for 10 sec at 180 psi for 250-psi tank pressures, with the rate of flow of oxygen at 0.49 lb/sec.
After Hitler's visit, it finally it became clear to Dornberger that either support for the project would have to come from the highest level, or that Peenemuende should abandon rocket research and be devoted to more pressing war needs.
Meanwhile the results of the air war over London showed that the A4 could be an economic weapon. Bombers were averaging only 5 to 6 missions, dropping only 6 to 8 tonnes of bombs before being shot down. Once the loss of trained flying crews was considered, the bomber cost 30 times more than the A4 to deliver a tonne of explosives on London compared to the expendable A4 at its production price of 38,000 Marks. But time was being lost in convincing others in the German leadership that the missile should be put into production.
These tests (P5-P12) ran through Aug. 4, 1939. The new gas generator was used in eight static tests at the desert launching lower. The two best tests on July 17 and Aug. 4, 1939 gave lifts of 700 lb for about 15 sec, with flow of oxygen at 4 lb/sec and gasoline at 3 lb/sec; jet velocities were in excess of 3200 ft/sec. This completed the series of 19 proving-stand tests. Average interval between tests 7 days
The vertical take-off interceptor would reach 8 km altitude in 53 seconds and then manoeuvre toward the aircraft to be intercepted. The design was developed further by Fieseler as the Fi-166, which retained the rocket takeoff but used a turbojet for a longer cruising flight. The Ministry finally rejected the vertical-takeoff rocket interceptor concept at the end of 1941. The concept was revived at the end of the war as the Bachem Natter.
Von Brauchtisch obtained the highest priority for development of the A4. This was used in early 1940 to get 4,000 soldiers with the necessary engineering and technical backgrounds released from the Army and sent to Peenemuende's 'Versuchskommando-Nord'. Nevertheless there was a constant fight for priority in obtaining materials.
New test series at Greifswalder Oie. The island had changed a lot, with massive new concrete installations. Three A3's were flown with a new Siemens control system. The first was launched vertically, reaching 7 km at 45 seconds into the flight at the time of engine cut-off. Both the drogue and main parachutes functioned correctly, and the rocket splashed down in the harbour and was recovered a half hour later by a motor boat (the rocket could float for up to two hours before water entering the empty propellant tanks would sink it).
This was the first test of the pitch-over manoeuvre required for the operational A4. The test went perfectly - the rocket pitched over 4 seconds after lift-off, reaching 4 km altitude, and was 6 km downrange from the launch point when the drogue parachute deployed. The rocket was recovered from the ocean successfully. This was finally a complete success after seven years of developmental effort. But the rocket had not broken the sound barrier.
By adding wings to the A4, the 800 m/s of kinetic energy the rocket had at cut-off could be exploited in a glide attack, extending the range of the missile from 250 km to 550 km. Such a supersonic aircraft had never been flown and presented many aerodynamic and engineering problems in 1943. Various tests of the A4's with wings began in early 1940. These were successful, and the configuration was dubbed the A9. The trajectory for such a missile involved a boost to an apogee of 29 km, then a stable glide at 20 km altitude at a speed of 1250 m/s. At the end of the glide, the missile would have descended to 5 km altitude, then make a vertical dive on the target in the fashion of the Fi-103/V-1. The A9 would be equipped with wings with a total area of 13.5 sq m. A manned version of this boost-glide rocketplane was also designed. This could reach a conventional airfield 600 km from the launch point in only 17 minutes, landing at a speed of 160 kph. Another possibility to further extend range would be a catapult-launched A9, using the technology developed for the V-1. This would provide an extra velocity of 350 m/s, further extending the missile's potential range.
The tunnel was used an average of 500 hours per month. 1000 cubic metres of vacuum vessels were pumped to a 98% vacuum in three to five minutes by three banks of double vacuum pumps. When vented, they provided the tunnel with 20 seconds of run time at velocities from Mach 1.2 to Mach 4.0, or 1500 m/s. Models 4 to 5 cm in diameter x 30-40 cm long could be accommodated in the tunnel, instrumented at 110 data points. These tests showed that drag increased 70% at the sound barrier and that the centre of pressure on the missile moved back one-half calibre. The wind tunnel runs showed that the basic A4 shape was all right, but that it needed load-carrying wings and a new rudder for the higher-speed A9 glider version. Huge trial and error was required to develop an A9 configuration that was stable, but not so stable that the control surfaces were too large. An arrow wing was the best performing, but the control surfaces were then in the turbulent flow of the wing and inadequate. Swept wings provided 12% less glide ratio than the arrow wing, resulting in a 60 km loss of range. Trapezoidal wings were the final solution, the end of a long iterative process.
Peenemuende-developed delta wings were adapted to Army artillery rounds of the 105 mm flak gun and K5 280 mm cannon, decreasing drag by 35%. The result was an increase of 6 kg in the explosive load, a 6 kg increase in the iron mass of the round, but with a range increase from 59 to 90 km. Equipped with a new, lighter warhead, and a sabot boosting a slimmer round, the gun could shoot projectiles to a range of 135 to 150 km, with an accuracy of 2 per mill.
Section C tests would run through October 10, 1941. The series of twenty-four static and flight tests (P13-P36) was made with rockets of large fuel capacity, with the rocket motor, pumps, and turbines previously developed. These rockets averaged nearly 22 ft in length, and were 18 in, in diameter. They weighed empty from 190 to 240 lb. The liquid-oxygen load averaged about 140 lb, the gasoline 112 lb, making 'quarter-ton' loaded rockets.