Pratt & Whitney JT3D

JT3D/TF33
	JT3D-3B on a Royal Australian Air Force Boeing 707
Type	Turbofan
National origin	United States
Manufacturer	Pratt & Whitney
First run	1958
Major applications	Boeing 707 ; Boeing B-52H Stratofortress ; Boeing KC-135E Stratotanker ; Douglas DC-8 ; Lockheed C-141 Starlifter
Number built	c. 8,600
Developed from	Pratt & Whitney J57/JT3C

The Pratt & Whitney JT3D is an early turbofan aircraft 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.

Design and development

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]

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

JT3D-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 Sentry

TF33-PW-102/A

TF33-PW-103

Applications

Civilian (JT3D)

Military (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
- WC-135
Boeing CC-137
Boeing E-3 Sentry
Boeing VC-137B/C Stratoliner
Northrop Grumman E-8 Joint STARS
Lockheed C-141 Starlifter
Martin/General Dynamics RB-57F Canberra

Specifications (JT3D-8A / TF33-P-7)

Data 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 engine

References

^ 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 & 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

Official website

[1] 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

[2] sed on an article in Flight magazine 19 December 1958

[Pither-3] Tony Pither, The Boeing 707 720 and C-135, Air-Britain (Historians), 1998, ISBN 0-85130-236-X

[fgRFP-4] 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.

[5] 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.

[JAWA62-63-6] ^ ^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 & Co Ltd.

[AEotw6667-7] Wilkinson, Paul H. (1966). Aircraft engines of the World 1966/67 (21st ed.). London: Sir Isaac Pitman & Sons Ltd. p. 103.

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v t e Pratt & Whitney aircraft engines
Radial engines	R-985 R-1340 R-1535 R-1690 R-1830 R-1860 R-2000 R-2060 R-2180-A R-2180-E R-2270 R-2800 R-4360 Double Wasp Hornet (A) Hornet B Twin Hornet Twin Wasp (R-1830) Twin Wasp (R-2000) Twin Wasp E Twin Wasp Junior Wasp series Wasp Wasp Junior Wasp Major Yellow Jacket
H piston engines	X-1800/XH-2600 XH-3130 (XH-3730)
Free-piston gas turbines	PT1
Turbojets	JT3C JT4A JT6 JT7 JT8A JT9 JT11 JT12 J42 J48 J52 J57 J58 J60 J75 J91
Turbofans	GP7000† JT3D JT4D JT8D JT9D JTF10 JTF10A JT10D JTF14 JTF16 JTF17 JTF22 PW1000G PW1120 PW2000 PW4000 PW5000 PW6000 RTF-180† STF200 SuperFan† V2500† F100 F105 F117 F119 F135 F401 RM8† TF30 TF33 XA101 XA103
Turboprops/Turboshafts	APW34† JFTD12 PT2 PT3 PT4 PT5 T34 XT45 T52 XT57 T73 T800-APW† T900†
Propfans	578-DX†
Rocket engines	RL10
Aeroderivative gas turbine engines	GG3/FT3 GG4/FT4 FT8
Subsidiaries	Pratt & Whitney Canada Pratt & Whitney Rocketdyne
Key people	Leonard S. Hobbs George J. Mead Wright Parkins Perry Pratt Frederick Rentschler Richard "Dick" Soderberg Andrew Willgoos
† Joint development aeroengines See also: Pratt & Whitney Canada aeroengines

v t e United States military gas turbine aircraft engine designation system
Turbojets	J30 J31 J32 J33 J34 J35 J36 J37 XJ38 J39 J40 XJ41 J42 J43 J44 J45 J46 J47 J48 XJ49 J51 J52 J53 J54 J55 J56 J57 J58 J59 J60 J61 J63 J65 J67 J69 J71 J73 J75 J79 J81 J83 J85 J87 J89 J91 YJ93 J95 J97 J99 J100 YJ101 J102 J400 J401 J402 J403 J700
Turboprops/ Turboshafts	T30 T31 T33 T34 T35 T36 T37 T38 T39 T40 T41 T42 T43 T44 T45 T46 T47 T48 T49 T50 T51 T52 T53 T54 T55 T56 (variants) T57 T58 T60 T61 T62 T63 T64 T65 T66 T67 T68 T69 T70 T71 T72 T73 T74 T76 T78 T80 T100 T101 T400 T405 T406 T407 T408 T700 T701 T702 T703 T706 T708 LHTEC T800 APW T800 T900 T901
Turbofans	TF30 TF31 TF32 TF33 TF34 TF35 TF37 TF39 TF41 F100 F101 F102 F103 F104 F105 F106 F107 F108 F109 F110 F112 F113 F117 F118 F119 YF120 F121 F122 F124 F125 F126 F127 F128 F129 F130 F135 F136 F137 F138 F400 F401 F402 F404 F405 F408 F412 F414 F415
Adaptive cycle engines	XA100 XA101 XA102 XA103

v t e United States Air Force system numbers
100–199	100 101 P 102 103 104 105 106¹ 107 A-1 A-2 108¹ 109¹ 110 111¹ 112 113¹ 114¹ 115¹ 116¹ 117 L M 118 A L P 119 C/F E L T Y 120 121 122 123 124 125 126 127¹ 128 129 130 131 132 A B 133 134¹ 135 136¹ 137¹ 138 139 140 141¹ 142 143–197¹ 198 199 B C D Y
200–299	200 201 A/L B/W E 202 203¹ 204 205 206 207¹ 208 209¹ 210 211¹ 212 213 214 215¹ 216 217 218 219¹ 220 221 222 A G 223¹ 224 225¹ 226 227–238¹ 239 240–278¹ 279 280–298¹ 299
300–399	300 301¹ 302 303 304¹ 305¹ 306 A/L B 307 308 309 310¹ 311¹ 312¹ 313¹ 314 315 A-1 A-2 316 317 318¹ 319 320¹ 321 322¹ 323 324 L M/N 325 326 327 E 328 E 329 F 330¹ 331¹ 332¹ 333¹ 334¹ 335 336 337 338–379¹ 380 A/B/E/F/N P 381–397¹ 398 399 A B
400–499	400 B/C/N E G/H M 401 402 403¹ 404 405 B C D 406¹ 407 408¹ 409¹ 410 E L 411 E L 412 413 414 L M 415 416 L M (I) M (II) P Q 417 418 L M 419¹ 420 L/W 421¹ 422 423 424 425 426 L M 427 L M 428 A L 429 430 431 G (I) G (II) 432 433 434 435 A L 436 437 438 439 440 441 A D L 442 443 444¹ 445 L M 446 447 448¹ 449¹ 450 451 D L 452 453 454¹ 455 456 457¹ 458 459 460 L 461 462 463 464 465 466 467 468 469 470 471 L (I) L (II) 472 473 474 L N 475¹ 476 E 477 478 A T 479¹ 480 481 L 482 E L M/Z 483 484 L M N 485 L Z 486 487 488 489 490 L M 491¹ 492 493 494 495 L (I) L (II) 496 497 A L (I) L 498 A C D E L 499 A C D
500–599	500 501–519¹ 520 521–529¹ 530 531–541¹ 542 543–549¹ 550 A E 551–559¹ 560 A F 561–569¹ 570 571–579¹ 580 A E 581–589¹ 590 591 592 593–599¹
600–699	600 601 A L 602 A L 603 A L 604 605 606 607 608¹ 609 610¹ 611¹ 612¹ 613¹ 614 615¹ 616 617¹ 618 619¹ 620 621 A/B (I) B (II) 622 623 624 625 626¹ 627 628¹ 629¹ 630¹ 631¹ 632 633 634 A B 635 636¹ 637¹ 638 639 640 641 642 643 644¹ 645¹ 646¹ 647¹ 648 A D P 649 A B C D E F L P 650 651 652 653¹ 654¹ 655 A (I) A (II) P 656 657¹ 658¹ 659¹ 660 661 662¹ 663¹ 664 665 A (I) A (II) 666 A C/P 667 668 669¹ 670 671¹ 672 A M/P 673¹ 674 675 676¹ 677¹ 678¹ 679 680 681 D E 682¹ 683 A J V 684¹ 685 686 687 J P 688¹ 689¹ 690 691 C X Z 692¹ 693 694¹ 695 A B C L N P Q R S (I) S (II) 696¹ 697¹ 698¹ 699¹
700–799	700–735¹ 736 737¹ 738¹ 739¹ 740¹ 741 742 743 744¹ 745 746–753¹ 754 755–799¹
800–899	800¹ 801¹ 802 L (I) L (II) 803¹ 804¹ 805¹ 806 807 808–816¹ 817 818¹ 819¹ 820¹ 821¹ 822¹ 823 824–831¹ 832 833¹ 834 835–845¹ 846 847–899¹
900–999	900–951¹ 952 853¹ 854¹ 855¹ 956 957–967¹ 968
¹ Unknown or not assigned