Pratt & Whitney XT57

The Pratt & Whitney XT57 (company designation: PT5) was an axial-flow turboprop engine developed by Pratt & Whitney in the mid-1950s. The XT57 was developed from the Pratt & Whitney J57 turbojet.

Design and development
One XT57 (PT5), a turboprop development of the J57, was installed in the nose of a JC-124C (BuNo 52-1069), and tested in 1956.

Rated at 15000 hp, the XT57 was the most powerful turboprop engine in existence at the time, and it remains the most powerful turboprop ever built in the United States. The engine had a split-compressor (also known as "two-spool") design.

Intended for use on the Douglas C-132 aircraft, the XT57 turboprop used a Hamilton Standard Model B48P6A propeller with a diameter of 20 ft, which was the largest diameter propeller to be used in flight at the time. The single-rotation propeller had four hollow steel blades, a maximum blade chord of 22 in, a length of 5.5 ft, and a weight of 3600 lb.

In the late 1950s, the XT57 was studied for use in a United States Navy-proposed, nuclear-powered conversion of a Saunders-Roe Princess flying boat. Despite not having entered service, the engine was selected because it had passed a Pratt & Whitney 150-hour testing program, which involved running the engine for 5,000–7,000 hours.

Variants

 * T57/PT5: A turboprop engine driving a 20 ft Hamilton Standard Turbo-Hydromatic propeller, 15000 hp turboprop to be used on the Douglas C-132, a Mach 0.8 speed military transport aircraft.

Engines on display
The XT57 engine is on display at the Pratt & Whitney museum in East Hartford, Connecticut.

Applications

 * T57 turboprop
 * Douglas JC-124C Globemaster II testbed
 * Douglas C-132 (not built)