Pratt & Whitney Canada PT6

The PT6, manufactured by Pratt & Whitney Canada, is the most popular turboprop aircraft engine in history. [ [http://www.utc.com/profile/facts/history.htm United Technologies history] ] It is produced in a wide variety of models, covering the power range between 580 and 920 shp in the original series, and up to 1,940 shp in the "large" line. The PT6 family are particularly well known for their extremely high reliability, with MTBO's on the order of 9000 hours in some models. [ [http://www.pwc.ca/en/3_0/3_0_1/3_0_1_2_2.asp PT6A Model Specifications] ] In US military use, they are known as the T74.

Development

Development of the PT6 family started in the late 1950s, apparently as a modern replacement for the Pratt & Whitney Wasp radial engines they were producing at that time. It first flew on 30 May 1961, mounted on a Beech 18 aircraft at de Havilland Canada's Downsview, Ontario facility. Full-scale production started in 1963, entering service the next year. By its 40th anniversary in 2001 over 36,000 PT6As had been delivered, not including the other versions. [ [http://www.findarticles.com/p/articles/mi_m0EIN/is_2001_June_18/ai_75610122 Pratt & Whitney Canada's PT6 Turboprop Marks 40 Years of In-flight Success] ] The engine is used in over 100 different applications.

The engine consists of two sections that can be easily separated for maintenance. In the "gas-generator section" air enters through a grill into the low-pressure three-stage axial compressor, then into a single-stage centrifugal compressor, through the annular reverse-flow combustion chamber, and finally through a single-stage turbine that powers the compressors at about 45,000 rpm. Some power is also taken off of the compressor end of the shaft to power an accessories section, which also loads the engine Fact|date=June 2007 when idle to keep it from racing out of control. The hot gas from the gas generator section then flows into a separate "power section" of the engine, containing a single-stage turbine driving the power take-off system at about 30,000 rpm. For turboprop use, this powers a two-stage planetary output reduction gearbox, which turns the propeller at a speed of 1,900 to 2,200 rpm. The exhaust gas then escapes through two side mounted ducts in the power turbine housing, and is directed away from the engine in order to provide about 600 lbf of thrust. The engine is arranged such that the power turbines are mounted inside the combustion chamber, reducing overall length.

In most aircraft installations the PT6 is mounted backwards in the nacelle, so that the intake side of the engine is facing the rear of the aircraft, and the exhaust side can directly drive the propeller. Intake air is usually fed to the engine via an underside mounted duct, and the two exhaust outlets are directed rearward. This arrangement also aids maintenance by allowing the entire propeller section to be easily removed along with the power section, exposing the gas-generator section.

Several other versions of the PT6 have appeared over time. The PT6A large added an additional power turbine stage and a deeper output reduction, producing almost twice the power output, between 1,090 and 1,920 shp. The PT6B is a helicopter turboshaft model, featuring an offset reduction gearbox with a freewheeling clutch and power turbine governor, producing 1,000 hp at 4,500 rpm. The PT6C is a helicopter model, with a single side-mounted exhaust, producing 2,000 hp at 30,000 rpm, which is stepped down in a user-supplied gearbox. The PT6T Twin-Pac consists of two PT6 engines driving a common output reduction gearbox, producing almost 4,000 hp at 6,000 rpm. The ST6 is a version intended for stationary applications, originally developed for the UAC TurboTrain, and now widely used as auxiliary power units on large aircraft, as well as many other roles. [ [http://www.turbokart.com/about_pt6.htm Pratt & Whitney PT6A-42 Turboprop] - primary source for the description]

When de Havilland Canada asked for a much larger engine, roughly twice the power of the PT6 Large, P&WC responded with a design initially known as the PT7. During development this was renamed to become the Pratt & Whitney Canada PW100. Unlike the PT6, the PW100 uses a three-spool turbine with the power turbine attached to the rest of the engine, meaning it cannot be completely removed as with the PT6. The PW100 also uses two centrifugal compressors driven by the first two turbine stages, as opposed to the mix of axial and centrifugal compressors in the PT6. This makes the engine somewhat harder to disassemble, but results in a much more compact engine.

Variants

PT6A

The PT6A is a free turbine providing 500 to 1,940 shaft horsepower (433 to 1,447 kW). The variants, and some of the aircraft that they power, are:

;PT6A-6: "Small" engine of 525 equivalent shaft horsepower (eshp) and 500 shaft horsepower (shp); fitted to the:
Beech 18 series (turbine conversion)
Beechcraft Model 87
Beechcraft 65-90 King Air
de Havilland Canada DHC-2 Mk. III Turbo Beaver
Pilatus PC-6/B [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/3f313b5c37af6fda862572ce005e0741/$FILE/7a15%20rev%2013.pdf Pilatus PC-6 Series Type Certificate] retrieved 2007-12-15.]

;PT6A-11: "Small" engine of 528 eshp and 500 shp; fitted to the:
Air Tractor AT-400 and AT-402A
Ayres S2R-T11 Turbo Thrush
Piper T1040
Piper PA-31T1 Cheyenne I and Cheyenne IA
Weatherly 620

;PT6A-15AG: "Small" engine optimised for agricultural aircraft of 715 eshp and 680 shp; fitted to the:
Air Tractor AT-400, AT-402 and AT-402B
Air Tractor AT-502 and AT-502B
Ayres S2R-T15 Turbo Thrush
Frakes Turbocat
Grumman/Schweizer/Ag Cat Corp G-164B-15T Ag Cat Turbine [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/f3d62ab31562cdda85256744005fd416/$FILE/1a16.pdf G-164 Series Type Certificate] retrieved 2007-12-15.]

;PT6A-20: "Small" engine of 579 eshp and 550 shp; fitted to the:
Aero Commander 680T (PT6A conversion) [ [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/53feb89eef94ee4386256ee6004ac8d0/$FILE/sa710sw.pdf Supplemental Type Certificate No. SA710SW] retrieved 2007-12-13.]
Air Tractor AT-400A and AT-402A
Beech 18 series (turbine conversion)
Beechcraft 65-90, 65-A90, B90 and C90 King Air
Beechcraft U-21 Ute
Beechcraft Model 99 and A99
de Havilland Canada DHC-2 Mk. III Turbo Beaver
Grumman/Schweizer/Ag Cat Corp G-164B-20T Ag Cat Turbine
Grumman Goose (turbine conversion) [ [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/ccd7c0e051e1113e8625738e006c0c73/$FILE/SA1320WE.pdf Supplemental Type Certificate No. SA1320WE] retrieved 2007-12-13.]
Pilatus PC-6/B1
Swearingen SA26-T Merlin IIA

;PT6A-21: "Small" engine of 580 eshp and 550 shp; fitted to the:
Air Tractor AT-400A and AT-402A [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/3cc21b1fb1c6264e86257355005fb9b9/$FILE/A17SW.pdf Air Tractor 400 and 500 Series Type Certificate] retrieved 2007-12-15.]
Beechcraft A36TC Bonanza (turbine conversion) [ [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/503ed598db2814ac862573280063cc6c/$FILE/SA01156SE.pdf Supplemental Type Certificate No. SA01156SE] retrieved 2007-12-13.]
Beechcraft C90, C90-1 and C90A King Air
JetPROP DLX

;PT6A-25: "Small" engine of 580 eshp and 550 shp (-25, -25A) or 783 eshp and 750 shp (-25C); fitted to the:
Beechcraft T-34C Mentor
Daewoo SHI KTX-1
Embraer EMB 312 Tucano
FTS Turbo Firecracker
Pilatus PC-7
PZL-130T Turbo Orlik and PZL-130TC-II Orlik

;PT6A-27: "Small" engine of 715 eshp and 680 shp; fitted to the:
Air Tractor AT-400, AT-402 and AT-402B
Air Tractor AT-502 and AT-502B
Beech 18 series (turbine conversion) [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/53e0c9c085bb8347862570c8005a77e3/$FILE/SA1016WE.pdf Supplemental Type Certificate No. SA1016WE] retrieved 2007-12-13.]
Beechcraft Model 99A, A99A and B99
de Havilland Canada DHC-3 Otter (turbine conversion)
de Havilland Canada DHC-6 Twin Otter
Embraer EMB 110 Bandeirante
Helio AU-24A
Let L-410 Turbolet
Harbin Y-12
Pilatus PC-6/B2
Saunders ST-27

;PT6A-28: "Small" engine of 715 eshp and 680 shp; fitted to the:
Beechcraft E90 King Air
Beechcraft Model 99A, A99A and B99
Beechcraft 100 and A100 King Air
Embraer EMB 121 Xingu
Piper PA-31T Cheyenne and Cheyenne II

;PT6A-29: "Small" engine of 778 eshp and 750 shp; fitted to the:
Beechcraft RU-21B Ute [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/8c3d574efe5ea4a58625733a006a4a8b/$FILE/3a20.pdf Beechcraft 90 Series King Air Type Certificate] retrieved 2007-12-15.]

;PT6A-34: "Small" engine of 783 eshp and 750 shp; fitted to the:
Air Tractor AT-400, AT-402 and AT-402B
Air Tractor AT-502, AT-502B and AT-503A
Antilles Super Goose [ [http://www.antillesseaplanes.com/specs.htm Antilles Super Goose specifications page.] Retrieved: 21 September 2008.]
Ayres S2R-T34 Turbo Thrush
Beechcraft A100 King Air
Beechcraft T-44 Pegasus
Beechcraft RU-21C Ute
Cessna P210N (turbine conversion)
Cessna 404 (turbine conversion) [ [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/6FE95A1FE0CBC31B85256CC200122C8A?OpenDocument&Highlight=pt6a FAA Regulatory and Guidance Library] retrieved 2007-12-13.]
Embraer EMB 110 and EMB 111 Bandeirante
Embraer Carajá
Frakes Mallard
Frakes Turbocat
Grumman/Schweizer/Ag Cat Corp G-164B-34T Ag Cat Turbine
JetPROP DLX
NDN Fieldmaster
PAC Cresco
PAC 750XL
PZL-106BTU-34 Turbo Kruk
Quest Kodiak 100 [ [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/51cc725f7a72a0aa862573a70078ff73/$FILE/A00007SE.pdf Quest Kodiak 100 Type Certificate] retrieved 2007-12-13.]
Saunders ST-28
Vazar Dash 3 Turbine Otter

;PT6A-35: "Small" engine of 787 eshp and 750 shp; fitted to the:
Beechcraft Duke (turbine conversion) [ [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/0ae89ceeeda662b1862571720051364b/$FILE/SA01672SE.pdf Supplemental Type Certificate No. SA01672SE] retrieved 2007-12-13.]
JetPROP DLX

;PT6A-36: "Small" engine of 783 eshp and 750 shp; fitted to the:
Air Tractor AT-502 and AT-502B
Beechcraft Model C99 [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/c0a846816b9bfac386257385005c5f33/$FILE/A14ce.pdf Beechcraft Model 99 Series Airliner and Model 100 Series King Air Type Certificate] retrieved 2007-12-15.]

;PT6A-38: "Large" engine of 801 eshp and 750 shp; fitted to the:
Beechcraft C-12 Huron

;PT6A-40: "Large" engine of 749 eshp and 700 shp; fitted to the:
Beechcraft Lightning

;PT6A-41: "Large" engine of 903 eshp and 850 shp; fitted to the:
Beechcraft 200, 200C, 200T and 200CT Super King Air
Beechcraft C-12 Huron and RC-12 Guardrail
Gulfstream American Hustler 400
Piper PA-42 Cheyenne III

;PT6A-42: "Large" engine of 903 eshp and 850 shp; fitted to the:
Aero Ae 270 Ibis
Beechcraft B200, B200C, B200T and B200CT Super King Air/King Air
Beechcraft C-12 Huron and RC-12 Guardrail
Dominion UV-23 Scout [ [http://www.globalsecurity.org/military/systems/aircraft/uv-23.htm Global Security UV-23 page] retrieved 2008-01-05.]
Embraer EMB 121 Xingu
Piper PA-46-500TP Meridian

;PT6A-45: "Large" engine of 1,070 eshp and 1,020 shp; fitted to the:
Air Tractor AT-502A and AT-503
Air Tractor AT-602
Air Tractor AT-802 and AT-802A
Ayres S2R-T45 Turbo Thrush
Frakes Mohawk 298
PZL-Mielec M-18 Dromader (turbine conversion)
Shorts 330

;PT6A-50: "Large" engine of 1,022 eshp and 973 shp; fitted to the:
de Havilland Canada Dash 7

;PT6A-52: "Large" engine of 898 eshp and 850 shp; fitted to the:
Beechcraft B200GT and B200CGT King Air

;PT6A-60: "Large" engine of 1,113 eshp and 1,050 shp (-60, -60A) or 1,081 ehsp and 1,020 shp (-60AG); fitted to the:
Air Tractor AT-502A
Air Tractor AT-602 [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/58c2f869cf17389d862572b5006c822d/$FILE/A19SW.pdf Air Tractor 602 and 802 Series Type Certificate] retrieved 2007-12-15.]
Ayres S2R-T660 Turbo Thrush
Beechcraft 300 and 300LW Super King Air 300
Beechcraft B300 and B300C Super King Air 350/King Air 350

;PT6A-61: "Large" engine of 902 eshp and 850 shp; fitted to the:
Piper PA-42-720 Cheyenne IIIA

;PT6A-62: "Large" engine of 1,218 eshp and 950 shp [ [http://www.pwc.ca/en/includes/pop_template_2.asp?MotorID=160 PT6A-62 data] retrieved 2007-12-29.] ; fitted to the:
Pilatus PC-9
Korea Aerospace Industries KT-1 [ [http://www.forecastinternational.com/samples/617_2005.pdf "The Market for Military Fixed-Wing Trainer Aircraft"] "Forecast International" Market Segment Analysis, retrieved 2007-01-05.]

;PT6A-64: "Large" engine of 747 eshp and 700 shp [http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/767FC021FB0A2B83862573A2004B0270/$FILE/E26NE.pdf PT6A -64/-66/-67/-68 Series Type Certificate] retrieved 2007-12-29.] ; fitted to the:
Socata TBM700 ;PT6A-65: "Large" engine of 1,249 eshp and 1,173 shp (-65B, -65R) or 1,298 eshp and 1,220 shp (-65AG, -65AR); fitted to the:
Air Tractor AT-502A
Air Tractor AT-602
Air Tractor AT-802 and AT-802A
Antonov An-28 (-65B)
Ayres S2R-T65 Turbo Thrush
AMI DC-3
Beechcraft 1900 and 1900C
CASA C-212 series 300P
Greenwich Aircraft DC-3
PZL M-28 Skytruck
Shorts 360
Shorts C-23 Sherpa

;PT6A-66: "Large" engine of 905 eshp and 850 shp (-66, -66A, -66D) or 1,010 eshp and 950 shp (-66B); fitted to the:
AASI Jetcruzer
Aero Ae 270 Ibis
NAL Saras
Piaggio P.180 Avanti
Socata TBM850
Pilatus PC-12

;PT6A-67: "Large" engine of 1,272 eshp and 1,200 shp (-67, -67A, -67B, -67P), 1,285 eshp and 1,214 shp (-67D), 1,294 eshp and 1,220 shp (-67AF, -67AG, -67R, -67T), or 1,796 eshp and 1,700 shp (-67F); fitted to the:
Air Tractor AT-802 and AT-802A
Basler BT-67
Beechcraft RC-12 Guardrail
Beechcraft 1900D
Beechcraft Starship
Conair S2 Turbo Firecat
Greenwich Aircraft DC-3 [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/ACA7E965B47F885785256CC2000C5AC4?OpenDocument&Highlight=pt6a FAA Regulatory and Guidance Library] retrieved 2007-12-13.]
Pilatus PC-12
Shorts 360

;PT6A-68: "Large" engine of 1,324 eshp and 1,250 shp; fitted to the:
Embraer EMB 314 Super Tucano
Pilatus PC-21
Raytheon T-6 Texan II

;PT6A-110: "Small" engine of 502 eshp and 475 shp; fitted to the:
Dornier Do 128 Turbo Skyservant

;PT6A-112: "Small" engine of 528 eshp and 500 shp; fitted to the:
Cessna 425
Reims F406 Caravan II

;PT6A-114: "Small" engine of 632 eshp and 600 shp (-114) or 725 eshp and 675 shp (-114A); fitted to the:
Cessna 208 "Caravan".

;PT6A-116: "Small" engine of 736 eshp and 700 shp; fitted to the:

;PT6A-121: "Small" engine of 647 eshp and 615 shp [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/8488466f515340978625730c00495ff4/$FILE/E4EA_rev24.pdf Pratt & Whitney Canada PT6 Series Type Certificate] retrieved 2007-12-15.] ; fitted to the:

;PT6A-135: "Small" engine of 787 eshp and 750 shp; fitted to the:
Beechcraft C90GT, F90 and F90-1 King Air
Cessna P210N (turbine conversion) [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/E032F1E92372C6FE85256CC20008C62A?OpenDocument&Highlight=pt6a FAA Regulatory and Guidance Library] retrieved 2007-12-13.]
Cessna 421C (turbine conversion) [ [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/D56AE6EE422F63AB85256CC100820F95?OpenDocument&Highlight=pt6a FAA Regulatory and Guidance Library] retrieved 2007-12-13.]
Cessna 425
Dornier Seawings Seastar
Embraer EMB 121 Xingu
Piper PA-31P (turbine conversion) [ [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/76A60A0D9C20C0DF85256CC2000E3B00?OpenDocument&Highlight=sa4268sw FAA Regulatory and Guidance Library] retrieved 2008-01-05.]
Piper PA-31T2 Cheyenne IIXL
Scaled Composites ATTT
Vazar Dash 3 Turbine Otter [http://www.pwc.ca/en/3_0/3_0_5/3_0_5_1_3.asp Pratt & Whitney Canada PT6A applications] retrieved 2007-12-13.] [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/0/4b47ab8e0cb273188625703e00569198/$FILE/Sa3777nm.pdf Supplemental Type Certificate No. SA3777NM] retrieved 2007-12-13.]

PT6B

B.

PT6C

The PT6C is a 1600 to 2300 horsepower (1190 to 1720 kW) engine for helicopters/tiltrotors. It powers the AgustaWestland AW139 and the PZL-Swidnik Sokol helicopters, and the Bell/Agusta BA609 tiltrotor.

PT6T

The PT6T/T400 (Twin-Pac) is a twinned turboshaft designed for helicopters. It powers the Agusta-Bell 212 and 412, the Bell AH-1J and AH-1T, CH-146 Griffon, and UH-1N Twin Huey, and the Sikorsky S-58T.

T6

The ST6 is a variant of the PT6 that was originally developed as a powerplant for the UAC TurboTrain locomotives, but later developed as a stationary power generator and auxiliary power unit.

References

External links

* http://www.biaero.com/technical_and_regulatory_links.htm
* http://www.pwc.ca/
* http://www.utc.com/