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JT12
Type	Turbojet
National origin	United States
Manufacturer	Pratt & Whitney
First run	1957
Major applications	North American Sabreliner
Number built	800+
Variants	Pratt & Whitney T73

The Pratt & Whitney JT12 (US military designation J60) is a small turbojet engine. The Pratt & Whitney T73 (Pratt & Whitney JFTD12) is a related turboshaft engine.^[2]

Design and development

The J60 conception and project design began in July 1957 at United Aircraft of Canada (now Pratt & Whitney Canada) in Montreal. The project design details were transferred to the main P&W company in East Hartford and in May 1958, the first prototype, with military designation YJ60-P-1 commenced testing.

Flight tests were completed in early 1959; followed by the delivery of the new JT12A-5 engines in July 1959. These were for the two Canadair CL-41 prototype trainers with a rating of 12.9 kN (2,900 lb st). The modified JT12A-3 turbojets with a basic rating of 14.69 kN (3,300 lb st) were tested in the two Lockheed XV-4A Hummingbird VTOL research aircraft. The next version, JT12A-21, had an afterburner which delivered a maximum thrust of 17.91 kN (4,025 lb st).

Variants

Data from Janes^[3]
YJ60-P-1: prototype
J60-P-3
J60-P-3A
J60-P-4
J60-P-5
J60-P-6
J60-P-9
T73: Military designation of the Pratt & Whitney JFTD12 free power turbine turboshaft version of the J60.
JT12A-3LH
JT12A-5: (J60-P-3 / -3A / -5 / -6 / -9) Take-off ratings from 2,900 lbf (12.9 kN) to 3,001 lbf (13.35 kN).
JT12A-6: Essentially similar to the -5
JT12A-6A
JT12A-7: (J60-P-4) up-rated to 3,300 lbf (15 kN)
JT12A-8
JT12A-8A
JT12A-21: An after-burning version developing 4,023 lbf (18 kN) thrust wet.
FT12: Turboshaft versions for marine use.
JFTD12: Company designation of the Pratt & Whitney T73 free power turbine turbo-shaft version of the J60.

Applications

Civilian (JT12)

Lockheed JetStar
North American Sabreliner
Aérotrain Experimental 02 (French Touch in 60')

Military (J60)

Specifications (JT12A-8A)

Data from Aircraft engines of the World 1966/67^[4]

General characteristics

Type: Commercial turbojet
Length: 78 in (2,000 mm)
Diameter: 22 in (560 mm)
Dry weight: 468 lb (212 kg)

Components

Compressor: 9-stage axial compressor
Combustors: Cannular - 8 burner cans in an annular casing
Turbine: 2-stage axial turbine
Fuel type: ASTM-A-1 / MIL-J-5624 / JP-1 / JP-4 / JP-5
Oil system: Return pressure spray system at 45 psi (310 kPa)

Performance

Maximum thrust: 3,300 lbf (14.68 kN)
Overall pressure ratio: 6.7:1
Air mass flow: 50.5 lb (22.9 kg) per second
Turbine inlet temperature: 872 °C (1,602 °F; 1,145 K)
Specific fuel consumption: 0.89 lb/lbf (91 kg/kN) per hour
Thrust-to-weight ratio: 7.05

References

^ Connors, p.285
^ Greg Goebel's Vectorsite
^ Janes: JT12
^ Wilkinson, Paul H. (1966). Aircraft engines of the World 1966/67 (21st ed.). London: Sir Isaac Pitman & Sons Ltd. p. 103.

Connors, Jack; Allen, Ned (2010). The Engines of Pratt & Whitney: A Technical History. Reston. Virginia: American Institute of Aeronautics and Astronautics. ISBN 978-1-60086-711-8.