Pratt & Whitney J52

J52/JT8A
A J52 cut-out showing its two spools
Type	Turbojet
National origin	United States
Manufacturer	Pratt & Whitney
First run	1955
Major applications	Douglas A-4 Skyhawk Grumman A-6 Intruder Northrop Grumman EA-6B Prowler
Number built	>5,000
Developed from	Pratt & Whitney J57
Developed into	Pratt & Whitney JT8D

The Pratt & Whitney J52 (company designation JT8A) is an axial-flow dual-spool turbojet engine originally designed for the United States Navy, in the 9,000 lbf-class. It powered the A-6 Intruder and the AGM-28 Hound Dog cruise missile. The engine is still in use in 2011 in models of the A-4 Skyhawk and the EA-6B Prowler.

The engine provided the basis for the Pratt & Whitney JT8D, a popular civilian low-bypass turbofan engine.

The J52 was developed in the mid-1950s for the US Navy as a scaled-down derivative of the J57/JT3A. It was initially intended to power the A4D-3 Skyhawk, an advanced avionics model that was canceled in 1957. After being canceled, the U.S. Air Force selected the J52 to power the AGM-28 Hound Dog cruise missile. The engine was designed with several unique features for this application, including a "conical centerbody mounted in the intake" and a "variable central plug ... in the nozzle". Then, in 1958, the US Navy selected the engine to power what became the A-6 Intruder.

The J52-P-6 model, designed for the YA2F-1 (YA-6A) Intruder, had a unique nozzle that could be angled downward at 23 degrees for STOL takeoffs; this was not used on production A-6s. Returning full circle, the J52 was selected to power the A4D-5, another model of the A-4 Skyhawk, remaining in all subsequent new-built models.

The twin-spool J52 employs a split 12-stage axial compressor consisting of a five-stage low pressure unit and a seven-stage high pressure unit. Behind the compressor is a nine-unit can-annular combustion chamber and a two-stage split turbine.

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