Pratt & Whitney F117

Pratt & Whitney F117. The Pratt & Whitney F117 is a high-bypass turbofan aircraft engine developed for military transport aircraft. It is a militarized derivative of the commercial Pratt & Whitney PW2000 engine, designed to provide exceptional reliability and performance for strategic airlift missions. The engine is most famously associated with powering the Boeing C-17 Globemaster III, a cornerstone of United States Air Force and allied global air mobility.

Development and design

The development of the engine stemmed from a United States Air Force requirement for a new powerplant for its next-generation strategic airlifter, which would become the Boeing C-17 Globemaster III. Pratt & Whitney leveraged the core technology of its successful commercial Pratt & Whitney PW2000 engine, which also powered aircraft like the Boeing 757. The militarization process involved significant modifications to enhance durability and operability in harsh conditions, including resistance to Foreign object damage and the ability to use a wider range of Jet fuel grades. Key design features included a Full Authority Digital Engine Control (FADEC) system for optimized performance and a distinctive Mixed exhaust nozzle. The engine's design prioritized high Thrust at lower Airspeeds for improved short-field takeoff performance, a critical requirement for the C-17's mission profile.

Operational history

The engine entered service with the first operational Boeing C-17 Globemaster III delivered to Charleston Air Force Base in 1993. It quickly proved integral to global United States Transportation Command operations, supporting deployments during conflicts such as the War in Afghanistan and the Iraq War. The engine's reliability was demonstrated in demanding environments worldwide, from austere forward operating strips to major hubs like Ramstein Air Base. Beyond combat operations, the powerplant has been crucial for Humanitarian aid missions, including disaster relief after events like the 2010 Haiti earthquake and the 2004 Indian Ocean earthquake and tsunami. The fleet has accumulated millions of flight hours, with engines maintained through the United States Air Force's depots and support contracts with Pratt & Whitney.

Variants

* F117-PW-100: The initial and primary production variant developed for the Boeing C-17 Globemaster III for the United States Air Force. * F117-PW-100 (C-17A): Designation for engines powering the standard C-17A model operated by the United States Air Force and international customers like the Royal Air Force and Royal Australian Air Force. * F117-PW-100 (MD-17): A variant associated with the experimental Boeing Bird of Prey technology demonstrator aircraft, which utilized a single engine for propulsion.

Specifications (F117-PW-100)

* Type: Twin-spool, high-bypass Turbofan * Length: Approximately 165 inches (4.19 m) * Diameter: Approximately 84 inches (2.13 m) fan diameter * Dry weight: Approximately 7,100 lb (3,220 kg) * Compressor: 1 Fan, 4-stage Low-pressure compressor, 12-stage High-pressure compressor * Combustors: Annular combustion chamber * Turbine: 2-stage High-pressure turbine, 5-stage Low-pressure turbine * Maximum thrust: 40,440 lbf (180.0 kN) * Overall pressure ratio: 30.4:1 * Bypass ratio: 5.8:1 * Fuel consumption: * Thrust-to-weight ratio: 5.7:1

Operators

The primary operator is the United States Air Force, which fields the engine on its fleet of Boeing C-17 Globemaster III aircraft operated by Air Mobility Command units such as the 437th Airlift Wing and the 62nd Airlift Wing. Key international operators of the C-17 and its engine include the Royal Air Force (RAF Brize Norton), the Royal Australian Air Force (RAAF Base Amberley), the Canadian Armed Forces (8 Wing Trenton), and the Indian Air Force. The engine was also used by the Qatar Emiri Air Force and the United Arab Emirates Air Force. The multinational Strategic Airlift Capability program, based at Pápa Air Base in Hungary, also operates C-17s powered by this engine.

Category:Aircraft engines Category:Pratt & Whitney aircraft engines Category:Turbofan engines 1980–1989