The Pratt & Whitney JT3D is an early turbofanaircraft engine derived from the Pratt & Whitney JT3C. It was first run in 1958 and was first flown in 1959 under a B-45 Tornado test aircraft. Over 8,000 JT3Ds were produced between 1959 and 1985. Most JT3D engines still in service today are used on military aircraft, where the engine is referred to by its US military designation of TF33.
Aware of the competition from the Rolls-Royce Conway turbofan, Pratt & Whitney decided to develop the JT3D turbofan from the JT3C turbojet for later deliveries of the Boeing 707 and the Douglas DC-8, then nearing entry into service. A 2-stage fan replaced the first 3 stages of the 9-stage JT3C LP compressor. On the LP turbine, the second stage was enlarged and a third stage added.
Unlike GE with the CJ805-23, Pratt & Whitney had not undertaken any transonic fan research prior to designing the JT3D, so they were unable to incorporate a single stage unit into the specification.[1] Instead P&W designed a 2-stage unit based on some research they had done to support the J91 nuclear turbojet.
On the Boeing 707 the JT3D fan nacelle was relatively short, whereas the Douglas DC-8 installation had a full-length fan cowl. Pratt & Whitney provided a kit whereby JT3Cs could be converted to the JT3D specification, and performance, during an overhaul.[2]
In 1959, important orders for the engine were the Boeing 707-120B and Boeing 720B when American Airlines ordered one 707 powered by JT3D turbofans and KLM ordered a JT3D-powered Douglas DC-8. Earlier 707s and DC-8s had been powered by the JT3C and JT4A turbojets, and the improved efficiency of the turbofan soon attracted the airlines. A JT3D-powered 707-123B and 720-023B (the suffix B was to indicate a turbofan-powered aircraft) entered service with American Airlines on the same day, March 12, 1961.
The Boeing KC-135 Stratotankers were all originally powered by turbojet engines. With the demise of many airline 707s, the United States Air Force took the opportunity to buy the surplus airframes and use the engines to re-fit the KC-135As used by the Air National Guard and reserve squadrons with the civilian JT3D (designated TF33-PW-102). Over 150 aircraft were modified and the former KC-135A was re-designated the KC-135E.[3]
JT3Ds from Boeing 707s are used to re-fit USAF KC-135As, 1984.
After long service for both airlines and air forces, the number of JT3D-powered aircraft is steadily decreasing. One hundred thirty five KC-135s use the JT3D, while 354 were fitted with CFM International CFM56 engines, which provide greater thrust, lower fuel consumption, and increased operational flexibility due to their lower noise footprint. The noise of the JT3D is one of the reasons NATO has debated re-fitting their E-3 Sentry AWACS fleet, since the aircraft are subject to restrictions that aircraft with modern engines are not. Operational flexibility would be further increased due to the ability of higher power engines to increase the ceiling of the aircraft, extending the horizon for radar surveillance; for instance, RAF, French and Saudi E-3s routinely fly higher than NATO/USAF counterparts.
In 1961, the TF33-powered Boeing B-52H Stratofortress entered service. The "H" model of the B-52 was the only production variant of the heavy bomber to be fitted with turbofan engines, and is the only model remaining in United States Air Force service. It is expected to remain as a mainstay of the Air Force heavy bomber fleet until at least 2040, with options for replacing the 8 TF33 engines with more modern equivalents being considered. In April 2020, the USAF released a request for proposals for 608 commercial replacement engines, with the plan to award the contract in May 2021.[4] In September 2021, the USAF announced that the TF33 would be replaced by the Rolls-Royce F130.[5]
^Smith, George E.; Mindell, David A. (2000), "The Emergence of the Turbofan Engine", Atmospheric Flight in the Twentieth Century, Kluwer Academic Publishers, pp. 107–155, ISBN9789401143790, from the original on 2022-06-10, retrieved 2021-08-27
^based on an article in Flight magazine 19 December 1958
^Tony Pither, The Boeing 707 720 and C-135, Air-Britain (Historians), 1998, ISBN0-85130-236-X
^Garrett Reim (27 April 2020). "US Air Force issues draft request for proposal to replace B-52 engines". Flight International. from the original on 28 April 2020. Retrieved 28 April 2020.
^Young, Sarah (27 September 2021). "U.S. picks Rolls-Royce for B-52 engines in potential $2.6 bln deal". Reuters. from the original on 27 September 2021. Retrieved 27 September 2021.
^ abcdefghiTaylor, John W.R. FRHistS. ARAeS (1962). Jane's All the World's Aircraft 1962-63. London: Sampson, Low, Marston & Co Ltd.
^Wilkinson, Paul H. (1966). Aircraft engines of the World 1966/67 (21st ed.). London: Sir Isaac Pitman & Sons Ltd. p. 103.
Bibliography
Taylor, John W.R. FRHistS. ARAeS (1962). Jane's All the World's Aircraft 1962-63. London: Sampson, Low, Marston & Co Ltd.
External links
Wikimedia Commons has media related to Pratt & Whitney TF33.
Official website
August 20, 2023
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The Pratt amp Whitney JT3D is an early turbofan aircraft engine derived from the Pratt amp Whitney JT3C It was first run in 1958 and was first flown in 1959 under a B 45 Tornado test aircraft Over 8 000 JT3Ds were produced between 1959 and 1985 Most JT3D engines still in service today are used on military aircraft where the engine is referred to by its US military designation of TF33 JT3D TF33JT3D 3B on a Royal Australian Air Force Boeing 707Type TurbofanNational origin United StatesManufacturer Pratt amp WhitneyFirst run 1958Major applications Boeing 707 Boeing B 52H Stratofortress Boeing KC 135E Stratotanker Douglas DC 8 Lockheed C 141 StarlifterNumber built c 8 600Developed from Pratt amp Whitney J57 JT3C Contents 1 Design and development 2 Variants 3 Applications 4 Specifications JT3D 8A TF33 P 7 4 1 General characteristics 4 2 Components 4 3 Performance 5 See also 6 References 7 Bibliography 8 External linksDesign and development EditAware of the competition from the Rolls Royce Conway turbofan Pratt amp Whitney decided to develop the JT3D turbofan from the JT3C turbojet for later deliveries of the Boeing 707 and the Douglas DC 8 then nearing entry into service A 2 stage fan replaced the first 3 stages of the 9 stage JT3C LP compressor On the LP turbine the second stage was enlarged and a third stage added Unlike GE with the CJ805 23 Pratt amp Whitney had not undertaken any transonic fan research prior to designing the JT3D so they were unable to incorporate a single stage unit into the specification 1 Instead P amp W designed a 2 stage unit based on some research they had done to support the J91 nuclear turbojet On the Boeing 707 the JT3D fan nacelle was relatively short whereas the Douglas DC 8 installation had a full length fan cowl Pratt amp Whitney provided a kit whereby JT3Cs could be converted to the JT3D specification and performance during an overhaul 2 In 1959 important orders for the engine were the Boeing 707 120B and Boeing 720B when American Airlines ordered one 707 powered by JT3D turbofans and KLM ordered a JT3D powered Douglas DC 8 Earlier 707s and DC 8s had been powered by the JT3C and JT4A turbojets and the improved efficiency of the turbofan soon attracted the airlines A JT3D powered 707 123B and 720 023B the suffix B was to indicate a turbofan powered aircraft entered service with American Airlines on the same day March 12 1961 The Boeing KC 135 Stratotankers were all originally powered by turbojet engines With the demise of many airline 707s the United States Air Force took the opportunity to buy the surplus airframes and use the engines to re fit the KC 135As used by the Air National Guard and reserve squadrons with the civilian JT3D designated TF33 PW 102 Over 150 aircraft were modified and the former KC 135A was re designated the KC 135E 3 JT3Ds from Boeing 707s are used to re fit USAF KC 135As 1984 After long service for both airlines and air forces the number of JT3D powered aircraft is steadily decreasing One hundred thirty five KC 135s use the JT3D while 354 were fitted with CFM International CFM56 engines which provide greater thrust lower fuel consumption and increased operational flexibility due to their lower noise footprint The noise of the JT3D is one of the reasons NATO has debated re fitting their E 3 Sentry AWACS fleet since the aircraft are subject to restrictions that aircraft with modern engines are not Operational flexibility would be further increased due to the ability of higher power engines to increase the ceiling of the aircraft extending the horizon for radar surveillance for instance RAF French and Saudi E 3s routinely fly higher than NATO USAF counterparts In 1961 the TF33 powered Boeing B 52H Stratofortress entered service The H model of the B 52 was the only production variant of the heavy bomber to be fitted with turbofan engines and is the only model remaining in United States Air Force service It is expected to remain as a mainstay of the Air Force heavy bomber fleet until at least 2040 with options for replacing the 8 TF33 engines with more modern equivalents being considered In April 2020 the USAF released a request for proposals for 608 commercial replacement engines with the plan to award the contract in May 2021 4 In September 2021 the USAF announced that the TF33 would be replaced by the Rolls Royce F130 5 Variants Edit TF33 P 7 engine of a C 141BJT3D 1 17 000 lbf 75 62 kN thrust civil version Water injection optional 6 JT3D 2 TF33 P 3 17 000 lbf 75 62 kN 6 JT3D 3 18 000 lbf 80 07 kN Water injection optional 6 JT3D 3A TF33 P 5 18 000 lbf 80 07 kN 6 JT3D 3B 18 000 lbf 80 07 kN thrust civil version JT3D 5A TF33 P 7 18 000 lbf 80 07 kN Water injection optional 6 JT3D 8A TF33 P 7 18 000 lbf 80 07 kN Water injection optional 6 JT3D 7 19 000 lbf 84 52 kN thrust civil version JT3D 15 22 500 lbf 100 08 kN thrust civil version for the unbuilt 707 820 TF33 P 3 17 000 lbf 75 62 kN thrust for the Boeing B 52H Stratofortress 6 TF33 P 5 18 000 lbf 80 07 kN thrust for the Boeing KC 135 Stratotanker 6 TF33 P 7 21 000 lbf 93 41 kN thrust for the Lockheed C 141 Starlifter 6 TF33 P 9 18 000 lbf 80 07 kN thrust for the Boeing EC 135C and Boeing RC 135C TF33 P 11 16 000 lbf 71 17 kN thrust for the Martin RB 57F Canberra TF33 PW 100A 21 500 lbf 95 64 kN thrust for the Boeing E 3 SentryTF33 PW 102 ATF33 PW 103Applications Edit JT3D on a Douglas DC 8 TF33 JT3D on Boeing VC 137B at Seattle Museum of FlightCivilian JT3D Boeing 707 Boeing 720 Douglas DC 8 Shanghai Y 10Military TF33 Boeing B 52H Stratofortress Boeing C 18 Boeing C 135 series EC 135 KC 135D E Stratotanker re engined from retired donor airliners OC 135B Open Skies RC 135 Boeing CC 137 WC 135 Boeing E 3 Sentry Boeing VC 137B C Stratoliner Northrop Grumman E 8 Joint STARS Lockheed C 141 Starlifter Martin General Dynamics RB 57F CanberraSpecifications JT3D 8A TF33 P 7 EditData from Aircraft engines of the World 1966 67 7 General characteristics Type Turbofan Length 142 3 in 3 610 mm Diameter 53 in 1 300 mm Dry weight 4 605 lb 2 089 kg Components Compressor Axial flow 2 stage fan 6 stage LP compressor and 7 stage HP compressor Combustors cannular 8 flame tubes Turbine Axial flow single stage HP turbine and 3 stage LP turbine Fuel type Mil J 5624 JP 4 JP 5 Oil system Return system 50 psi 340 kPa Performance Maximum thrust 17 000 lbf 76 kN take off flat rated to ISA partial thrust restoration with water injection Overall pressure ratio 16 1 overall Bypass ratio 1 42 1 Air mass flow 500 lb s 230 kg s Turbine inlet temperature 1 150 K 880 C 1 610 F at take off SLS ISA Specific fuel consumption 0 78 lb lbf h 22 g kN s at 4 000 lbf 18 kN thrust M 0 82 35 000 ft 11 000 m ISA Thrust to weight ratio 3 9 bare engineSee also EditRelated development Pratt amp Whitney JT3C J57 Pratt amp Whitney JT4A J75Comparable engines Kuznetsov NK 8 Rolls Royce Conway Soloviev D 30Related lists List of aircraft enginesReferences Edit Smith George E Mindell David A 2000 The Emergence of the Turbofan Engine Atmospheric Flight in the Twentieth Century Kluwer Academic Publishers pp 107 155 ISBN 9789401143790 archived from the original on 2022 06 10 retrieved 2021 08 27 based on an article in Flight magazine 19 December 1958 Tony Pither The Boeing 707 720 and C 135 Air Britain Historians 1998 ISBN 0 85130 236 X Garrett Reim 27 April 2020 US Air Force issues draft request for proposal to replace B 52 engines Flight International Archived from the original on 28 April 2020 Retrieved 28 April 2020 Young Sarah 27 September 2021 U S picks Rolls Royce for B 52 engines in potential 2 6 bln deal Reuters Archived from the original on 27 September 2021 Retrieved 27 September 2021 a b c d e f g h i Taylor John W R FRHistS ARAeS 1962 Jane s All the World s Aircraft 1962 63 London Sampson Low Marston amp Co Ltd Wilkinson Paul H 1966 Aircraft engines of the World 1966 67 21st ed London Sir Isaac Pitman amp Sons Ltd p 103 Bibliography EditTaylor John W R FRHistS ARAeS 1962 Jane s All the World s Aircraft 1962 63 London Sampson Low Marston amp Co Ltd External links Edit Wikimedia Commons has media related to Pratt amp Whitney TF33 Official website Retrieved from https en wikipedia org w index php title Pratt 26 Whitney JT3D amp oldid 1125235754, wikipedia, wiki, book, books, library,
