Private (rocket)

Private was an experimental rocket developed by the California Institute of Technology on behalf of the United States Army. Tested in two different configurations, it provided the proof of concept that a fin-stabilised ballistic missile was technologically feasible, and led to the development of the Corporal ballistic missile. The Private was the second in a series of JPL rockets for the US Army whose names correspond to the progression in Army enlisted ranks, starting with Private and led to WAC Corporal, Corporal E, Corporal and finally Sergeant.

Private
Private F
FunctionExperimental rocket
ManufacturerGuggenheim Aeronautical Laboratory
Country of originUnited States
Size
Height2.34 metres (7 ft 8 in)
Diameter240 millimetres (9.6 in)
Width0.86 metres (2 ft 10 in) finspan
Mass240 kilograms (529 lb)
StagesTwo
Launch history
StatusRetired
Launch sitesCamp Irwin, Fort Bliss
Total launches41
First flightDecember 1, 1944
Last flightApril 13, 1945
Booster stage – T22
Engines4
Thrust24.5 kN (5,500 lbf) each
Burn time0.2 seconds
FuelSolid
Sustainer stage
Engines1
Thrust4.4 kN (990 lbf)
Burn time30 sec
FuelSolid

History

The Private program was begun in 1944 as an outgrowth of work by the California Institute of Technology's Guggenheim Aeronautical Laboratory that had produced the first practical jet-assisted take-off (JATO) rockets.[1] The ORDCIT (Ordinance Department California Institute of Technology) project was the Private A which was initiated on May 24, 1944. The Guggenheim Aeronautical Laboratory, California Institute of Technology (GALCIT) was reorganized as the Jet Propulsion Laboratory.[2] The objective was to progressively increase the size and range of missiles.[3] A GALCIT JATO rocket motor was used for research into the development of ballistic missiles. The first flight of the Private A rocket, developed under the direction of Tsien Hsue-shen,[4] took place in December 1944, conducted at Camp Irwin in California.[5]

Private A (XF10S1000) was an unguided, fin-stabilised ballistic rocket; it consisted of a JATO unit equipped with cruciform tail fins, and a set of four T22 booster rockets that were jettisoned after launch.[1] This made Private A the first multistage rocket to be flown in the United States.[6] The gross weight of Private A was 500 pounds.[7] 24 launches of Private A were conducted at Leach Springs, Camp Irwin between December 1 and December 16, 1944.[7] The tests were considered successful, Private A proving capable of flights of 18,000 metres (20,000 yd), and in January 1945 full funding for the ballistic missile program was provided, with GALCIT changing its name to Jet Propulsion Laboratory.[1]

A new version of Private, Private F, was developed; the rocket was similar to Private A, except an aircraft-like tail assembly was fitted instead of Private A's cruciform fins with forward canard surfaces.[8] The purpose of Private F was to determine the behavior of rockets with wings. Private F was flown from a launcher adjustable in elevation.[8] There were a number of configurations tested though they all were of the same basic configuration.[8]

A test series of Private F launches was conducted at Hueco Range, Fort Bliss in Texas between April 1 and April 13 in 1945.[5] These tests included two with dummy Private F bodies with only the boosters live.[9] The Private F had the propellant charge reduced from 191 pounds to 175 pounds to allow a 20 pound slow burning charge to provide tracking after engine burnout.[9] 17 launches were conducted, however none of them were successful; the rocket proving to have serious stability problems.[10] Every one of them rolled within seconds of launch.[9] It was determined that while fin stabilisation was workable, a winged missile would require an autopilot.[11]

Following the conclusion of the Private program, the lessons learned were applied to the development of the SSM-A-17 Corporal ballistic missile.[1]

Notes
  1. Parsch, Andreas (2004). "JPL (GALCIT) Private". Directory of U.S. Military Rockets and Missiles Appendix 4: Undesignated Vehicles. designation-systems.net. Retrieved 2014-05-15.
  2. Bragg 1961, p. 7.
  3. Bragg 1961, p. 8.
  4. Perrett, Bradley (2008-01-06). "Qian Xuesen Laid Foundation For Space Rise in China". Aviation Week & Space Technology. Archived from the original on 2011-05-21.
  5. Ley, Willy (1951 - revised edition 1958) [1944]. Rockets, Missiles and Space Travel. New York: The Viking Press. p. 250. Check date values in: |date= (help)
  6. Bragg 1961, p. 18.
  7. Kennedy 2009, p. 14.
  8. Bragg 1961, p. 36.
  9. Bragg 1961, p. 38.
  10. Bluth, John. "Malina, Frank Joseph". American National Biography Online. American National Biography. Retrieved 2008-06-13.
  11. Bragg 1961, p. 19.

References
  • Bragg, James W. (1961). Development of the Corporal: The Embryo of the Army Missile Program. Alabama: Reports and Historical Office, Army Ballistic Missile Agency, Army Ordinance Missile Command, Redstone Arsenal.CS1 maint: ref=harv (link)</ref>
  • Kennedy, Gregory P. (2009). The Rockets and Missiles of White Sands Proving Ground 1945-1958. Altglen, PA: Schiffer Publishing Ltd. ISBN 978-0-7643-3251-7.CS1 maint: ref=harv (link)
  • Malina, Frank (1972). "America's first long-range-missile and space exploration program: The ORDCIT project of the Jet Propulsion Laboratory, 1943–1946: A memoir". In Hall, R.C. (ed.). Essays on the History of Rocketry and Astronautics: Proceedings of the Third Through the Sixth History Symposia of the International Academy of Astronautics. II.CS1 maint: ref=harv (link)
  • Pendel, George, Strange Angel The Otherworldly Life of Rocket Scientist John Whitesides Parsons," Harcourt, Inc., New York,Library of Congress card number 55-6592, 1955
  • Private at Encyclopedia Astronautica
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