Pratt & Whitney Aircraft began development of its first production turbofan, the JT3D, in the late 1950s, by taking advantage of the service-proven JT3 (J57) gas generator, and adding a two-stage front fan. The JT3D made its first flight on a Boeing 707-120 on June 22, 1960, and powered the Boeing 707-120B, Boeing 720, and Douglas DC-8-50 airliners.

Although initially funded by the U.S. Air Force as the T33, the JT3D is an historic commercial jet transport engine. It was Pratt & Whitney's first commercial production turbofan, and fended off competition from the Rolls Royce Conway, which had a lower bypass ratio. It only required a simple modification to existing JT3 engines, which could be carried out by operators using a manufacturer provided kit. The conversion had a marginal effect on weight, but increased thrust by 35 percent, reduced fuel consumption by 15 to 22 percent, and cut takeoff noise by 10 dB.

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Date Circa late 1950s Country of Origin United States of America Type PROPULSION-Turbines (Jet) Manufacturer Pratt & Whitney
 Physical Description Type: Turbofan Thrust: 75,616 N (17,000 lb) at 6,650 rpm Compressor: 2-stage fan, 6-stage low pressure and 7-stage high pressure axial Combustor: 8 combustion chambers Turbine: Single-stage high pressure and 3-stage low pressure axial Weight: 1,882 kg (4,150 lb) Dimensions Length 346 cm (136.3 in.), Diameter 135 cm (53.1 in.)
 Materials Steel, Aluminum, Inconel, Stainless Steel, Magnesium, Preservative coating, Plastic, Textile
 Inventory Number A19721331000 Credit Line Gift of Pratt & Whitney Aircraft Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
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