Pratt & Whitney J48

The Pratt & Whitney J48 (company designation JT7 Turbo-Wasp) is a turbojet engine developed by Pratt & Whitney as a license-built version of the Rolls-Royce Tay. The Tay/J48 was an enlarged development of the Rolls-Royce Nene (Pratt & Whitney J42).

J48
A Pratt & Whitney J48
Type Turbojet
National origin United Kingdom/United States
Manufacturer Pratt & Whitney
Major applications Grumman F9F Panther
Grumman F-9 Cougar
Lockheed F-94 Starfire
Number built 4,108
Developed from Rolls-Royce RB.44 Tay

Design and development

In 1947, at the behest of the United States Navy, Pratt & Whitney entered into an agreement to produce the Rolls-Royce Nene centrifugal-flow turbojet engine under license as the J42 (company designation JT6), for use in the Grumman F9F Panther fighter aircraft.[1] Concerned that the Nene would not have the potential to cope with future weight growth in improved versions of the Panther, Luke Hobbs, vice president of engineering for P&W's parent company, the United Aircraft Corporation, requested that Rolls-Royce design a more powerful engine based on the Nene, which Pratt & Whitney would also produce.

By 1948, Rolls-Royce had designed the Tay turbojet, also a centrifugal-flow design. However, as Rolls-Royce was then developing an improved design with an axial compressor, which would become the Avon, the development and production of the Tay turbojet was left to Pratt & Whitney.[1][2] However, Rolls-Royce retained the rights to the Tay outside of the United States.

The Tay/J48 was a thirty percent enlargement of the preceding Nene/J42, and was produced both with and without afterburning.[2]

Operational history

Several aircraft types used the J48 engine during the 1950s, including the Grumman F9F-5 Panther.[3] and Grumman F9F-6/F9F-8 Cougar,[4] The U.S. Air Force's Lockheed F-94C Starfire[5] and North American YF-93 used afterburning versions of the J48 engine.[6]

Variants

Data from The Engines of Pratt & Whitney: A Technical History.[7]

J48-P-1
6,000 lbf (27 kN) dry, 8,000 lbf (36 kN) thrust with afterburning
J48-P-2
6,250 lbf (27.8 kN), 7,000 lbf (31 kN) thrust with water injection
J48-P-3
6,000 lbf (27 kN), 8,000 lbf (36 kN) thrust with afterburning
J48-P-5
6,350 lbf (28.2 kN), 8,750 lbf (38.9 kN) thrust with afterburning
J48-P-6
6,250 lbf (27.8 kN), 7,000 lbf (31 kN) thrust with water injection
J48-P-6a
6,250 lbf (27.8 kN), 7,000 lbf (31 kN) thrust with water injection
J48-P-7
6,350 lbf (28.2 kN), 8,750 lbf (38.9 kN) thrust with afterburning
J48-P-8
7,250 lbf (32.2 kN) thrust
J48-P-8A
7,250 lbf (32.2 kN) thrust
Turbo-Wasp JT-7
Commercial engines / company designation

Applications

Specifications (J48-P-8A)
A Pratt & Whitney J48 with afterburner

Data from Aircraft engines of the World 1957[8]

General characteristics
  • Type: turbojet with water injection[9]
  • Length: 109.75 in (2,788 mm) without fixed nozzle
  • Diameter: 50.5 in (1,280 mm)
  • Frontal area: 13.9 sq ft (1.29 m2)
  • Dry weight: 2,080 lb (940 kg) dry

Components
  • Compressor: single-stage double-sided centrifugal compressor
  • Combustors: nine interconnected can combustion chambers
  • Turbine: single stage axial
  • Fuel type: aviation kerosene / JP-4
  • Oil system: pressure spray with scavenge at 40 psi (280 kPa)

Performance

See also

Related development

Related lists

References
Notes
  1. Connors, p.202
  2. Gunston 2006, p.195.
  3. F9F Panther, U.S. Navy Historical Office. Accessed 2011-01-06.
  4. Bishop and Chant 2004, p. 154
  5. RAF Flying Review "TECHNICAL GEN" authors: staff, September 1962 p. 59
  6. North American YF-93A. National Museum of the US Air Force fact sheet. Accessed 2017-07-16
  7. Connors, p.210
  8. Wilkinson, Paul H. (1957). Aircraft engines of the World 1957 (15th ed.). London: Sir Isaac Pitman & Sons Ltd. pp. 98–99.
  9. Wilkinson, Paul H. (1955). Aircraft engines of the World 1955 (13th ed.). London: Sir Isaac Pitman & Sons Ltd.
Bibliography
  • Bishop, Chris; Chris Chant (2004). Aircraft Carriers: The world's greatest naval vessels and their aircraft. Minneapolis, MN: Zenith Press. ISBN 978-0-7603-2005-1.
  • Connors, Jack (2010). The Engines of Pratt & Whitney: A Technical History. Reston. Virginia: American Institute of Aeronautics and Astronautics. ISBN 978-1-60086-711-8.
  • Gunston, Bill (2006). World Encyclopedia of Aero Engines, 5th Edition. Phoenix Mill, Gloucestershire, England, UK: Sutton Publishing Limited. ISBN 0-7509-4479-X.
  • Kay, Anthony L. (2007). Turbojet History and Development 1930–1960 Volume 2:USSR, USA, Japan, France, Canada, Sweden, Switzerland, Italy and Hungary (1st ed.). Ramsbury: The Crowood Press. ISBN 978-1861269393.
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