Encyclopedia Astronautica
Bumper-WAC



bumper.jpg
V-2
German short range ballistic test vehicle. Pioneering US demonstration of a two stage launch vehicle, coupling a V-2 with a WAC Corporal. The first ballistic missile fired from Cape Canaveral.

In February 1946, Malina at the Jet Propulsion Laboratory calculated that a two-stage research rocket, consisting of a captured German V-2 as first stage and JPL's small WAC Corporal as the second stage, could achieve Mach 9. In October the Army funded the project, code-named 'Bumper', under the umbrella of General Electric's Hermes program. Bumper would require solution of the problems of stage separation and rocket ignition at high altitude. The V-2 was only altered at the nose - rails were fitted into which the Wac Corporal's fins slotted. The WAC however was extensively modified, the resulting model being designated the Bumper Wac. Canted fins with 50% more area than the ground-launch WAC design were intended to impart the necessary stability for the high-altitude release atop the V-2. However the first tests showed the fins were ineffective, and spin rockets were added to stabilize the WAC at high altitude.

The rockets were staged by throttling back the V-2's engine when a predetermined speed was achieved. The V-2 then sent a signal to the Bumper Wac to ignite its engine. The WAC's thrust burned through a wire, signaling the V-2 to cut off its engine. The WAC could then slide out of its rails and begin its free flight.

In May 1948 the first Bumper was launched from White Sands with a dummy upper stage and a small solid-propellant charge to test stage separation. The first all-up flight was on 30 September 1948, but the Wac's engine exploded on ignition. The cause was found and corrected. On the fourth flight the V-2 failed. Finally the fifth flight, on 24 February 1949 was a success. The WAC reached a record altitude of 393 km

The V-2 failed again on the sixth flight, which ended high-altitude attempts. The last two Bumpers instead were fired horizontally once in the upper atmosphere to meet the original objective - aerodynamic data at hypersonic speeds. These long-range launches could not be made from land-locked New Mexico. The Army selected a launch site at Cape Canaveral in Florida, and the two Bumpers launched from there were the first use of the facility. The WAC failed on the first attempt, but on the last launch of the program, on 29 July 1950, the WAC was accelerated to 5260 kph.

Failures: 5. First Fail Date: 1948-08-19. Last Fail Date: 1950-07-24.

AKA: RTV-G-4.
Gross mass: 12,862 kg (28,355 lb).
Height: 17.25 m (56.61 ft).
Diameter: 1.65 m (5.42 ft).
Span: 3.56 m (11.69 ft).
Thrust: 267.00 kN (60,023 lbf).
Apogee: 250 km (150 mi).
First Launch: 1948.05.13.
Last Launch: 1950.07.29.
Number: 8 .

More... - Chronology...


Associated Countries
See also
  • A4 The V-2, known as the A4 to its developers, was the basis for most of the rocketry that exists in the world today. It was ineffective as a weapon of war, but represented a quantum leap in technology. The A1, A2, A3, and A5 were steps in the development of the missile. Later versions - the A6 through A12 - were planned to take the Third Reich to the planets. More...
  • V-2 The V-2 ballistic missile (known to its designers as the A4) was the world's first operational liquid fuel rocket. It represented an enormous quantum leap in technology, financed by Nazi Germany in a huge development program that cost at least $ 2 billion in 1944 dollars. 6,084 V-2 missiles were built, 95% of them by 20,000 slave labourer in the last seven months of World War II at a unit price of $ 17,877. More...

Associated Manufacturers and Agencies
  • GE American manufacturer of rockets, spacecraft, and rocket engines. General Electric Corporation, USA. More...

Associated Launch Sites
  • White Sands White Sands Missile Range occupies an area 160 x 65 km in the Tularosa Basin of southern New Mexico, across the Sacramento Mountain range from Roswell. In the 1930's, Robert Goddard, after surveying weather conditions and population densities, had selected Roswell for his pioneering rocket tests. White Sands, a true desert area, was even more unpopulated than Roswell. German advances in rocketry during World War II impelled the US Army to begin programs to exploit this technology. The White Sands Proving Ground was established for testing German and American long-range rockets on 9 July 1945. Seven days later the first atomic bomb was exploded at Trinity Site, near the north boundary of the range. The first launch of a Tiny Tim rocket was on 26 September 1945. On 11 October a Tiny Tim boosted a WAC Corporal rocket from the tower. This was the first use of Launch Complex 33, later to be used for V-2, Nike, Viking, Corporal, Lance and Multiple Launch Rocket System testing. More...
  • Cape Canaveral America's largest launch center, used for all manned launches. Today only six of the 40 launch complexes built here remain in use. Located at or near Cape Canaveral are the Kennedy Space Center on Merritt Island, used by NASA for Saturn V and Space Shuttle launches; Patrick AFB on Cape Canaveral itself, operated the US Department of Defense and handling most other launches; the commercial Spaceport Florida; the air-launched launch vehicle and missile Drop Zone off Mayport, Florida, located at 29.00 N 79.00 W, and an offshore submarine-launched ballistic missile launch area. All of these take advantage of the extensive down-range tracking facilities that once extended from the Cape, through the Caribbean, South Atlantic, and to South Africa and the Indian Ocean. More...
  • Cape Canaveral LC3 X-17, V-2, Polaris, Bomarc launch complex. This complex was built to support the Bomarc interceptor missile program, but also supported Bumper, Jason, Redstone, X-17 and Polaris ballistic missile operations. The Air Force accepted Complex 3 in November 1951. The location had already supported the Cape's first major launch - Bumper 8 - on 24 July 1950. Following the last Bomarc launch in April 1960, some Bomarc support facilities were converted into a medical support area for Project Mercury. Later the complex supported tethered aerostat programs from 1983 through 1989. More...
  • White Sands LC33 Wac, Viking, V-2, Nike, Javelin, Hermes, Corporal, Atlas, Apache launch complex. LC 33 was the United States' first major rocket launch facility. The original Army Launch Area 1 complex consisted of a blockhouse, several concrete launching pads for captured German V-2 rockets, a 30-m tall launch tower for Aerobee rockets, a gantry and blast pit. More...

Associated Stages
  • A-4 Lox/Alcohol propellant rocket stage. Loaded/empty mass 12,805/4,008 kg. Thrust 311.80 kN. Vacuum specific impulse 239 seconds. V-2 production version. More...
  • WAC-1 Nitric acid/Aniline propellant rocket stage. Loaded/empty mass 300/125 kg. Thrust 6.70 kN. More...

Bumper-WAC Chronology


1948 May 13 - . 13:43 GMT - . Launch Site: White Sands. Launch Complex: White Sands LC33. LV Family: V-2. Launch Vehicle: Bumper-WAC. LV Configuration: Bumper-WAC Bumper 1.
  • Test / solar / ionosphere mission - . Nation: USA. Agency: USA. Apogee: 127 km (78 mi). Summary: First two-stage Bumper-Wac fired. Short duration Wac Corporal test; round successful. V-2 reached 112.4 km, 1220 m/s; Wac Corporal 127.6 km, 1345 m/s..

1948 August 19 - . 14:45 GMT - . Launch Site: White Sands. Launch Complex: White Sands LC33. LV Family: V-2. Launch Vehicle: Bumper-WAC. LV Configuration: Bumper-WAC Bumper 2. FAILURE: First stage failure..
  • Solar ultraviolet mission - . Nation: USA. Agency: USA. Apogee: 13 km (8 mi). Summary: First stage failure. V-2 reached 13.4 km, 380 m/s; WAC 13.1 km, 380 m/s..

1948 September 30 - . 15:30 GMT - . Launch Site: White Sands. Launch Complex: White Sands LC33. LV Family: V-2. Launch Vehicle: Bumper-WAC. LV Configuration: Bumper-WAC Bumper 3. FAILURE: Failure in the second stage, explosion prior to separation..
  • Test / solar ultraviolet / x-ray mission - . Nation: USA. Agency: USA. Apogee: 150 km (90 mi). Summary: V-2 reached 150.6 km, 1410 m/s; WAC destroyed..

1948 November 1 - . 14:24 GMT - . Launch Site: White Sands. Launch Complex: White Sands LC33. LV Family: V-2. Launch Vehicle: Bumper-WAC. LV Configuration: Bumper-WAC Bumper 4. FAILURE: Failure in first stage due to break in alcohol piping..
  • Test mission - . Nation: USA. Agency: USA. Apogee: 5.00 km (3.10 mi). Summary: V-2 reached 5 km, 390 m/s; WAC destroyed..

1949 February 24 - . 22:14 GMT - . Launch Site: White Sands. Launch Complex: White Sands LC33. LV Family: V-2. Launch Vehicle: Bumper-WAC. LV Configuration: Bumper-WAC Bumper 5.
  • Aeronomy mission - . Nation: USA. Agency: USA. Apogee: 393 km (244 mi). Fully fueled round used and attained highest altitude to that date. In addition to testing equipment the flight was used to measure upper air temperatures. V-2 reached 102 km, 1170 m/s; WAC 400 km, 2300 m/s. Provided information on ion densities in the F-region of the ionosphere.

1949 April 22 - . 00:17 GMT - . Launch Site: White Sands. Launch Complex: White Sands LC33. LV Family: V-2. Launch Vehicle: Bumper-WAC. LV Configuration: Bumper-WAC Bumper 6. FAILURE: Failed in the first stage..
  • Solar / aeronomy mission - . Nation: USA. Agency: USA. Apogee: 50 km (31 mi). Summary: Failed in the first stage. Vehicle was supposed to obtain cosmic ray data at altitudes unattainable by other rockets. V-2 reached 50 km, 790 m/s; WAC destroyed..

1950 July 24 - . 14:29 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC3. LV Family: V-2. Launch Vehicle: Bumper-WAC. LV Configuration: Bumper-WAC Bumper 8. FAILURE: Failure.
  • Test mission - . Nation: USA. Agency: USA; GE. Apogee: 20 km (12 mi). Bumper No. 8, a German V-2 with a 320 kg Army-JPL Wac Corporal, was fired from the Long-Range Proving Ground at Cape Canaveral at a very low angle of attack. The first-stage V-2 climbed 16 km before it exploded. The second-stage Corporal separated successfully, however, and traveled another 24 km. This was the first missile launch from Cape Canaveral.

1950 July 29 - . 11:25 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC3. LV Family: V-2. Launch Vehicle: Bumper-WAC. LV Configuration: Bumper-WAC Bumper 7.
  • Test mission - . Nation: USA. Agency: USA; GE. Apogee: 50 km (31 mi). Bumper No. 7 was the second missile launch from Cape Canaveral. This was to be a maximum range test of a two-stage vehicle, to study the problems in staging. The launch was delayed because of moisture in the vehicle. But when finally launched, the WAC achieved the highest sustained speed in the atmosphere to that date (Mach 9/2500 m/s) and 35.2 km altitude before impacting 305 km downrange.

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