Pratt & Whitney T73

The Pratt & Whitney T73 (company designation JFTD12) is a turboshaft engine.[2] Based on the JT12A, the T73 powered the Sikorsky CH-54 Tarhe and its civil counterpart Sikorsky S-64 Skycrane flying crane heavy-lift helicopters.[3] Turboshaft versions for naval use are known as the FT12.

JFTD12-4A mounted on an Erickson S-64E Aircrane
Type Turboshaft
Manufacturer Pratt & Whitney
Major applications Sikorsky CH-54 Tarhe
Sikorsky S-64 Skycrane
Number built 352[1]
Developed from Pratt & Whitney JT12


Basic military model, rated at 4,500 horsepower (3,355 kW) takeoff power and 4,000 horsepower (2,982 kW) maximum continuous power[4]
Higher-power military model with improved internal components; rated at 4,800 horsepower (3,579 kW) takeoff power and 4,430 horsepower (3,303 kW) maximum continuous power[4]
Civilian equivalent of T73-P-1[4]
Civilian equivalent of T73-P-700[4]
Marine powerplant


Specifications (T73-P-1)

Data from FAA Type Certificate E15EA

General characteristics

  • Type: Turboshaft
  • Length: 107.0 in (2,718 mm)
  • Diameter: 30.0 in (762 mm) maximum
  • Dry weight: 966 lbs (438 kg)


  • Compressor: nine stage axial compressor
  • Combustors: eight cans in annular configuration
  • Turbine: axial two stage gas generator turbine and axial two stage free turbine
  • Fuel type: aviation kerosene conforming to MIL-I-5161 E Grade I or II


  • Maximum power output: 4,500 horsepower (3,355 kW) takeoff, 4,000 horsepower (2,982 kW) maximum continuous; at sea level at or below -8°C (17°F)
  • Turbine inlet temperature: 688°C (1270°F)
  • Power-to-weight ratio: 4.66 hp/lb (7.66 kW/kg)

See also

Related development

Comparable engines

Related lists


  1. Connors, p.285
  2. Greg Goebel's Vectorsite
  3. Pratt & Whitney JT12 (United States), Aero-engines - Turbojet, Jane's Information Group, 2011.05.09
  4. Type Certificate Data Sheet E15EA, US DoT - FAA, 2011.09.12
  • 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.
  • Federal Aviation Administration Type Certificate Number E15EA, Revision 8 retrieved 14 February 2014
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