RTV-A-2 Hiroc
RTV-A-2 Hiroc | |
---|---|
Type | Supersonic Test Vehicle |
Place of origin | United States |
Production history | |
Designer | Consolidated-Vultee |
Designed | 1946 |
No. built | 3 |
Specifications | |
Mass | 1,205 pounds (547 kg) empty, 4,090 pounds (1,860 kg) full, |
Length | 31.5 feet (9.6 m) |
Width | 6 feet 10 inches (2.08 m) |
Diameter | 30 inches (760 mm) |
Engine | One XLR35-RM-1 engine with four chambers 2,000 pounds-force (8.9 kN) each |
Propellant | Liquid oxygen as oxidizer Ethanol as fuel |
The RTV-A-2 Hiroc (high-altitude rocket) was a product of the United States' first effort to develop an
Design
The Hiroc missiles were 31.5 feet (9.6 m) long, had a fin span (the maximum width of the rocket, accounting for the fins) of 6 feet 10 inches (2.08 m), a diameter of 30 inches (760 mm), an empty weight including payload of 1,205 pounds (547 kg) and a gross liftoff weight (GLOW) of 4,090 pounds (1,860 kg).[4][5]
The missile's propulsion system consisted of an
The Hiroc missile used liquid oxygen as its oxidizer, and alcohol for its fuel.[9] The Hiroc missile did not have separate tanks for its fuel and oxidizer, which were instead contained in one tank separated by two bulkheads.[10] The airframe of the rocket was supported by nitrogen gas pressure inside the tank, which could contain propellant or nitrogen gas when stored.[11][4][12] Having gas pressure provide rigidity to the structure reduced the empty weight by requiring less metallic components for structural reinforcement, but made the missile fragile because it required continuous pressurization.[13] The RTV-A-2 Hiroc had an airframe to propellant ratio three times better than the V-2.[1]
The
History
In April 1946,
As a result of drastic defense cuts in 1946 and for 1947 the USAAF's missile budget was cut in half from $29 to $13 million in what became known as "the black Christmas of 1946".[23] Many of the projects were canceled outright,[24] but MX-774 instead continued with reduced funding. The project was eventually canceled in June 1947 as the Army concentrated their efforts on cruise missiles, which were more promising at that time.[25]
Convair arranged to use the remaining contract funding to launch three of the rockets, which were named RTV-A-2 Hiroc.
Hiroc was flown from a pad 600 feet north the White Sands blockhouse. Tracking was provided Askania Cine theodolite, cameras, Sky-screen observers and four tracking telescopes and tracking radar. White Sands Proving Ground provided housing and support for the launch program.[26]
On the RTV-A-2 (MX-774), a camera recorded the flight data displayed upon an instrument panel. Both the number of parameters recorded and the survivability of the film record were limited. Therefore, dependence upon the intact recovery of this camera was problematic.[27]
During the test on 13 July, the Hiroc reached a maximum height of 6,200 feet (1,900 m), but lost thrust after 12.6 seconds and hit the ground at 48.5 seconds, 415 feet (126 m) from the launch pad. Due to a mistake in packing, the payload recovery parachute failed to open; a camera and a few other instruments survived, so the test was deemed a partial success.[5]
During the test on 27 September, the Hiroc reached an altitude of 24 miles (39 km) at 48 seconds and a maximum velocity of 2,350 feet per second (720 m/s). The parachute failed again, this time due to a battery problem; the Hiroc began to freefall before its oxygen tank exploded at 20,000 feet (6,100 m). This caused it to break up, but a camera and some instruments survived.[5]
During the test on 2 December, the Hiroc reached a maximum height of 30 miles (48 km) and reached a maximum velocity of 2,653 feet per second (809 m/s). The parachute failed to open yet again, this time due to the nose cone damaging it after being ejected, while the Hiroc was at an altitude of 121,000 feet (37,000 m) and moving at a speed of 1,500 feet per second (460 m/s). The camera was recovered, although it was partly damaged.[5] The third Hiroc had its nose compartment extended 34 inches to allow more instrumentation.[28]
All three Hiroc missiles had partially failed due to premature closure of the liquid oxygen valve. The cause of failure was determined from a light on the instrumentation coming on when the valve closed. The cause of the valve closing was traced to vibration of solenoids which caused pressure change in the hydrogen peroxide line which allowed nitrogen to vent from engine control lines with the resultant pressure drop closing the LOX valve.[29]
In late 1948 the Air Force proposed the continuation of the MX-774 program with an additional 15 missiles for high altitude research but the proposal was refused by the Research and Development Board's Committee on Guided Missiles which decided that the more capable Navy Viking Missile RTV-N-12 was a superior high altitude research vehicle.[30][31] Convair retained the core design team after program cancellation. That core led to Convair proposing a missile to meet the Air Force Request For Proposal MX-1593 which ultimately resulted in the Weapon System 107A, better known as the B-65/SM-65 Atlas, America's first ICBM.[32]
References
Citations
- ^ a b Neufeld 1990, pp. 47.
- ISBN 978-0-7643-3251-7, p 63
- ^ Rosenberg, Max, “The Air Force and the National Guided Missile Program 1944-1950,” USAF Historical Division Liaison Office, June 1964, p 48
- ^ a b c d Gruntman 2004, p. 214.
- ^ a b c d A Photo-History Of Atlas Precursors.
- ISBN 1-56347-649-5, p 314
- ^ Dornberger, Walter (1952). V-2. New York: Viking. English translation 1954.
- ^ a b Gruntman 2004, p. 215.
- ^ Rocket Engine, Liquid Fuel, XLR35-RM-1.
- ISBN 978-0-7643-3251-7, p 63
- ISBN 1-894959-18-3, p 17
- ^ Launius & Jenkins 2015, p. 73.
- ^ a b c d McMurran 2008, pp. 212–213.
- ^ McMurran 2008, p. 212.
- ^ Gruntman 2004, p. 216.
- ^ Astronautix.
- ISBN 1-894959-18-3, p 16
- ^ Gruntman 2004, p. 235.
- ^ a b Gruntman 2004, p. 212.
- ^ Rosenberg 2012, p. 42.
- ^ Gruntman 2004, p. 210.
- ISBN 1-894959-18-3, p 16
- ^ Rosenberg 2012, p. 77-78.
- ^ Rosenberg 2012, p. 44.
- ^ Neufeld 1990, pp. 36–37.
- ISBN 978-0-7643-3251-7, p 64
- ^ Neufeld 1990.
- ISBN 978-0-7643-3251-7, p 66
- ISBN 978-0-7643-3251-7, p 66
- ISBN 0-387-94137-1p 178-179
- ^ Rosenberg, Max, “The Air Force and the National Guided Missile Program 1944-1950,” USAF Historical Division Liaison Office, June 1964, p 50
- ISBN 1-894959-18-3, p 21-22
Books
- Gruntman, Mike (2004). Blazing The Trail: The Early History Of Spacecraft And Rocketry. Reston, Virginia: American Institute of Aeronautics and Astronautics. ISBN 9781563477058.
- Kennedy, Gregory P. (2009). The Rockets and Missiles of White Sands Proving Ground 1945-1958. Schiffer Publishing Ltd. ISBN 9780764332517.
- DeVorkin, Davidk (1993). Science With A Vengeance. Springer-Verlag. ISBN 0387941371.
- Launius, Roger D.; Jenkins, Dennis R. (2015). To Reach The High Frontier: A History Of U.S. Launch Vehicles. University Press of Kentucky. ISBN 9780813148076.
- McMurran, Marshall William (2008). Achieving Accuracy: A Legacy of Computers and Missiles. Xlibris Publishing. ISBN 9781436381062.
- Mindling, George; Bolton, Robert (2008). U.S. Air Force Tactical Missiles. Lulu. ISBN 9780557000296.
- Neufeld, Jacob (1990). Development of Ballistic Missiles in the United States Air Force, 1945–1960. United States Government Printing. ISBN 9780160211546.
- Rosenberg, Max (2012). The Air Force and the National Guided Missile Program. Defense Lion. ISBN 9780985973001.
- Sutton, George (2005). History of Liquid Propllant Rocket Engines. American Institute of Aeronautics and Astronautics. ISBN 1563476495.
- DeVorkin, Davidk (1993). Science With A Vengeance. Springer-Verlag. ISBN 0387941371.
- Waller, Chuck; Powell, Joel (2005). Atlas the Ultimate Weapon. Apogee Books. ISBN 1894959183.
Websites
- "A Photo-History Of Atlas Precursors (PDF)". NasaSpaceflight.com. Retrieved 12 April 2017.
- "Hiroc". www.astronautix.com. Archived from the original on 28 December 2016. Retrieved 7 July 2017.
- "Rocket Engine, Liquid Fuel, XLR35-RM-1". National Air and Space Museum. 14 March 2016. Retrieved 7 July 2017.