Pratt & Whitney PW1000G

PW1000G
Type Geared turbofan
National origin United States
Manufacturer Pratt & Whitney
First run 2008
Major applications Airbus A320neo family
Bombardier CSeries
Embraer E-Jets E2
Irkut MC-21
Mitsubishi Regional Jet
Program cost $10 billion[1]
Unit cost $12 million[2]

The Pratt & Whitney PW1000G is a high-bypass geared turbofan engine family, currently selected as the exclusive engine for the Bombardier CSeries, Mitsubishi Regional Jet (MRJ), and Embraer's second generation E-Jets, and as an option on the Irkut MC-21 and Airbus A320neo. The project was previously known as the Geared Turbofan (GTF), and originally the Advanced Technology Fan Integrator (ATFI). The engine is expected to deliver reductions in fuel use and ground noise when used in next-generation aircraft. The PW1000G engine first entered commercial use in January 2016 with Lufthansa's first commercial Airbus A320neo flight.[3]

Development

mockup with compressor and turbine cutaway

Pratt & Whitney first attempted to build a geared turbofan starting around 1998, with the PW8000.[4] This essentially was an upgrade of the existing PW6000 that replaced the fan section with a gearing system and new single-stage fan.[5] After several years of development the PW8000 essentially disappeared.[6]

Soon afterwards the ATFI project appeared, using a PW308 core but with a new gearbox and a single-stage fan. It had its first run on March 16, 2001. This led to the Geared Turbofan (GTF) program, which was based around a newly designed core jointly developed with German MTU Aero Engines.

In addition to the geared turbofan, the initial designs included a variable-area fan nozzle (VAFN), which allows improvements in propulsive efficiency across a range of the flight envelope.[7] However, the VAFN has since been dropped from production designs due to high system weight.

In July 2008, the GTF was renamed PW1000G, the first in a new line of "PurePower" engines.[8] Pratt & Whitney claims the PW1000G is 16% more fuel efficient than current engines used on regional jets and single-aisle jets, as well as being up to 75% quieter.[9]

Flight testing

Flight testing on a 747SP, in #2 position

The engine was first tested on the Pratt & Whitney Boeing 747SP, then since October 14, 2008 on an Airbus A340-600 in Toulouse on the number two pylon.[10] Testing of the CSeries bound PW1524G model began in October 2010.[11] The PW1500G engine successfully achieved Transport Canada type certification on February 20, 2013.[12] The A320 engine, the PW1100G, was first tested on the 747SP on 15 May 2013.[13]

The first flight test on one of its intended production airframes, the Bombardier CS100, was on September 16, 2013.[14] The first flight of the Airbus A320neo followed on September 25, 2014.[15] The PW1100G engine successfully achieved FAA type certification on December 19, 2014.[16] The fourth variant of the engine, the PW1900G, first flew on November 3, 2015 from Mirabel in Canada fitted to the Boeing 747SP test aircraft.[17]

Introduction

Powering the Lufthansa first A320neo

Starting Times

The first delivery to a commercial operator, an A320neo to Lufthansa, occurred on January 20, 2016.[18] This was instead of Qatar Airways due to rotor bow, or thermal bowing, due to asymmetrical cooling after shut-down on the previous flight. Differences in temperature across the shaft section supporting the rotor lead to different thermal deformation of the shaft material, causing the rotor axis to bend; this results in an offset between the center of gravity of the bowed rotor and the bearing axis, causing a slight imbalance and potentially reducing the tight clearance between the rotor blade tips and the compressor wall. All production standard engines now feature a damper on the third and fourth shaft bearings to help stiffen the shaft and data from engines in service and under accelerated testing is expected to gradually reduce engine start times. According to P&W President Bob Leduc, "by the time we get to June (2016), it will be down to 200 seconds for start time and by the time we get to December (2016) we will be down to 150 seconds for start time".[19]

In an earnings briefing on 26th July the CEO of Pratt & Whitney's parent company United Technologies Gregory Hayes stated when asked about the start up issues on the PW1100G-JM; "On the technical stuff, I would tell you it is in the rearview mirror. The start time with the software drops have been pretty well addressed".[20] Airbus group chief Tom Enders said while releasing Airbus's 2016 first half financial results that the first upgraded "golden engine" would be delivered to Lufthansa in early August 2016.[21]

Initially, the PW1000G start up sequence took about seven minutes, compared to one to two and a half minute startups on the similar CFM56 and IAE V2500 engines; hardware fixes and software upgrades decreased the time required by a little over a minute, and cooling down both engines at the same time saved slightly over two minutes, for a total reduction of three and a half minutes. This modifications were included on new-build engines, as well as retrofitting existing units. Pratt & Whitney continued to improve start up times, with fuel-nozzle modifications and oil filling procedure changes expected to save another minute when introduced by the end of 2017.[22]

To create a better seal and reduce cooling time by 1 min, a cubic boron nitride coating was applied to the 11 integrally bladed rotors tips: the A321neo production engines start times will be similar to the V2500.[23]

Engine removals

As IndiGo and Go Air operate in humid, hot, polluted and salty environment, 42 engines were prematurely removed from those companies' aircraft by 24 February, with more to come and after certain warnings mandatory checks and possible repairs are due after only three flight hours instead of ten : 28 engine removals were due to an air seal leakage in the third bearing, allowing metal particles to enter the oil system, triggering detectors. Pratt & Whitney discovered these issues in 2015 and revised the design in 2016 after the 160th engine with improved bearing compartments and damping for the third and fourth bearings to offset the rotor-bow, with the repairs retrofitted on-wing after testing at Airbus and Pratt.[22] Boosting durability of the third bearing compartment air seal, the upgraded carbon seal package was certified on April 12 and can be retrofited over a typical night stop.[24]

Thirteen engine removals were due to borescope inspections revealing blocked cooling holes in combustion chamber panels, apparently due to saltier air, and Pratt & Whitney developed and tested a more durable combustor design to address a tone problem, with the fix to be introduced in September.[22]

Spirit Airlines reported that the bleed air system froze shut on occasion due to cold temperatures on four of its five A320neos, a problem also experienced by IndiGo, leading Spirit to impose a 30,000 feet (9,100 m) ceiling on their aircraft.[25]

As Pratt troubles persists, JetBlue Airways has switched its first three Airbus A321neos in 2018 to A321ceos and will now take delivery of its first A321neos in 2019 among its order for 60.[26]

On 12 July 2017, it was reported that IndiGo has grounded 9 out of its 22 A320neo because of engine troubles. [27]

Production

At the start of its production in 2016, each GTF was costing PW $10m to build, more than the sale price, but should become less than $2m per engine.[28] MTU provides the first four stages of the high-pressure compressor, the low-pressure turbine and other components. In October 2016, MTU started to deliver the engine assembled on its line to Airbus.[29]

In November 2016, Pratt had fixed the issue of engine start time and wants to deliver 150 powerplants by the year-end, 50 fewer than originally planned. This is because of low yield of Fan Blades when less than one-third were passing inspection at the start of the year compared to 75% success for the latest. 350-400 engine deliveries are targeted for 2017. Fuel-burn performance is 16% better than the IAE V2500 baseline, on target, and even 18% better in best cases.[30]

Design

By putting a 3:1 gearbox between the fan and the low-pressure spool, each spins at its optimal speed: 4,000–5,000 RPM for the fan and 12,000–15,000 RPM for the spool, the high-pressure spool spinning at more than 20,000 RPM. The 30,000 hp gearbox is designed as a lifetime item with no scheduled maintenance other than changing oil.[31] The A320 PW1100G fan has 20 blades, down from 36 in the CFM56-5B.[32]

As the higher bypass ratio and gear leverage a higher propulsive efficiency, there is less need for a high performance engine core than the CFM LEAP, leaving a larger fuel burn gain margin of 5-7% over the next decade, averaging 1% per year combined with gear ratio tweaks.[33]

Applications

It has been proposed for the Sukhoi Superjet 130,[42] and the Rekkof Aircraft F-120NG.[43]

Specifications

The PW1000 Family[44]
Model PW1100G[45] PW1400G PW1500G[46] PW1900G PW1700G PW1200G
Fan Diameter 81 in (206 cm) 73 in (185 cm) 56 in (142 cm)
Bypass ratio 12.5:1 12:1 9:1
Static Thrust 24,000–35,000 lbf
110–160 kN		 28,000–31,000 lbf
120–140 kN		 19,000–23,300 lbf
85–104 kN		 17,000–23,000 lbf
76–102 kN		 15,000–17,000 lbf
67–76 kN		 15,000 lbf
67 kN
Compressor Axial flow, 1 geared fan, 3 stage LPC, 8 stage HPC same except 2 stage LPC
Combustor Twin annular pre-swirl combustor[47]
Turbine Axial flow, 2-stage HP, 3-stage LP
Application A320neo family Irkut MC-21 CSeries E-Jets E2 190/195 E-Jets E2 175 MRJ70/90
Service entry January 2016 2018 15 July 2016 2018 2021 2020
Type Certificate Data sheet
Model PW1100G[48] PW1500G[49]
Length 3.401 m (133.898 in)[lower-alpha 1] 3.184 m (125.4 in)[lower-alpha 2]
fan case diameter 2.224 m (87.566 in) 2.006 m (79.0 in)
weight 2857.6 kg (6300 lb) 2177 kg (4800 lb)
Takeoff thrust 30G/33G: 147.28 kN / 33,110 lbf
27G: 120.43 kN / 27,075 lbf
24G/22G: 107.82 kN / 24,240 lbf		 19G: 87.96 kN / 19,775 lbf
21G: 97.73 kN / 21,970 lbf
24/25G: 108.54 kN / 24,400 lbf
Thrust-to-weight ratio 3.85 - 5.26 4.12 - 5.08

See also

Related development

Comparable engines
Related lists

Notes

  1. ↑ fan spinner face to aft flange
  2. ↑ (fan spinner face to aft #6 comp. bolt

References

  1. ↑ Guy Norris (Jun 2, 2017). "Boeing’s NMA Poses Propulsion Puzzle For Engine Makers". Aviation Week & Space Technology.
  2. ↑ "JetBlue Picks Pratt Over CFM for Engines Valued at $1.03 Billion". Bloomberg. December 15, 2011.
  3. ↑ Spaeth, Andreas (25 January 2016). "Onboard Lufthansa's First Airbus A320neo Flight - Airways Magazine".
  4. ↑ Bill Sweetman and Oliver Sutton (June 1, 1998). "Pratt & Whitney's surprise leap". Interavia Business & Technology. Highbeam Research.
  5. ↑ "Pratt & Whitney's next leap in engine technology". Aerospace Engineering Magazine Online. SAE International. 1998. Top 15 Technology Innovations.
  6. ↑ Robert Luedeman (April 17, 2006). "The Short Life and Untimely Demise of the PW8000". The Dougloid Papers.
  7. ↑ "P&W readies for CSeries "third knob" engine testing". Flight Global. 23 February 2011.
  8. ↑ "Farnborough '08: Pratt & Whitney Launches PurePower Engine Family". Aero-News Network. Jul 14, 2008.
  9. ↑ Peter Coy (October 15, 2015). "The Little Gear That Could Reshape the Jet Engine". Bloomberg.
  10. ↑ "Airbus-owned A340 flies P&W geared turbofan engine". Flight Global. October 14, 2008.
  11. ↑ "Pratt & Whitney geared PW1524G testing underway". Flight Global. October 30, 2010.
  12. ↑ "Transport Canada Certifies Pratt & Whitney PurePower® PW1500G Engine for Bombardier CSeries Aircraft" (Press release). Bombardier. February 13, 2013.
  13. ↑ "IN FOCUS: Pratt completes first flight of PW1100G engine". Flight Global. 3 June 2013.
  14. ↑ "Bombardier’s CSeries Aircraft Completes Historic First Flight" (Press release). Bombardier. September 16, 2013.
  15. ↑ "A320neo Completes First Flight". Aviation Week. Sep 25, 2014.
  16. ↑ "FAA Certifies PurePower® Engine for A320neo Aircraft" (Press release). Pratt & Whitney. December 19, 2014.
  17. ↑ "P&W launches engine flight test campaign for new Embraer jets". Flight International. 3 November 2015. p. 12.
  18. ↑ "Airbus Delivers A320neo to Lufthansa". Wall street journal. January 20, 2016.
  19. ↑ "New P&W President Has ‘Nothing To Hide' On GTF Starter Issue". Aviation Week. 16 February 2016.
  20. ↑ Thomson Reuters StreetEvents (July 26, 2016). "Edited Transcript of UTX earnings conference call or presentation 26-Jul-16". Yahoo Finance.
  21. ↑ "Airbus: Delivery of P&W 'golden' A320neo engine imminent". Flight Global. 27 July 2016.
  22. 1 2 3 Jens Flottau and Guy Norris (Mar 24, 2017). "Airlines Praise Airbus A320neo Performance, But Engine Issues Remain". Aviation Week & Space Technology.
  23. ↑ Mike Gerzanics (26 May 2017). "Flight test: A321neo stretches its legs". Flight Global.
  24. ↑ Guy Norris (Apr 20, 2017). "Pratt & Whitney begins A320neo engine seal upgrade". Air Transport World. Aviation Week.
  25. ↑ Benjamin Bearup (10 April 2017). "Report: Spirit A320neo Fleet Suffering PW1000G Engine Challenges". Airways Magazine.
  26. ↑ "JetBlue switches A321neos as Pratt troubles persist". Flight Global. 25 Apr 2017.
  27. ↑ http://timesofindia.indiatimes.com/india/gst-adds-to-engine-woes-almost-half-of-indigo-a-320-neo-fleet-grounded/articleshow/59553418.cms
  28. ↑ "Pontifications: GTF faces steep learning curve on costs". Leeham News. June 13, 2016.
  29. ↑ "MTU formally opens A320neo engine line". Flight Global. 21 October 2016.
  30. ↑ Guy Norris (Nov 28, 2016). "Pratt Sees Busy Year-End As It Targets GTF Catch-Up". Aviation Week & Space Technology.
  31. ↑ "Bjorn’s Corner: Engine architectures". Leeham News. 4 March 2016.
  32. ↑ Tim Wuerfel (May 26, 2017). "Flying The A321neo: Technology Upgrades Under The Skin". Aviation Week & Space Technology.
  33. ↑ Ernest S. Arvai (May 31, 2017). "An Update: GTF Engine from Pratt & Whitney". AirInsight.
  34. ↑ Jon Ostrower (30 Nov 2010). "Airbus set to launch A320 NEO". flight international.
  35. ↑ "Airbus offers new fuel saving engine options for A320 Family" (Press release). Airbus. 1 December 2010.
  36. ↑ Mary Kirby (13 Apr 2010). "P&W seals deal to begin design on GTF for Russia's MS-21". flight international.
  37. ↑ "PurePower PW1000G Engine". utc.com.
  38. ↑ "PurePower PW1700G & PW1900G Engines" (PDF). Pratt & Whitney.
  39. ↑ Ernest S. Arvai (February 6, 2013). "Embraer Launches E-Jet RE: Assessing the Impact". airinsight.com.
  40. ↑ "Pratt & Whitney Launches Geared Turbofan Engine with Mitsubishi Regional Jet" (Press release). Pratt & Whitney. 9 Oct 2007.
  41. ↑ Stephen Trimble (9 Oct 2007). "Pratt & Whitney Geared Turbofan engine selected to power Mitsubishi Regional Jet". Flight international.
  42. ↑ "Russia will start the production of Sukhoi SuperJet NG in 2019-2020". ruaviation.com. 2 August 2013.
  43. ↑ "Fokker 120 specifications". Rekkof Aircraft.
  44. ↑ "PW1000G". MTU.
  45. ↑ "Pratt & Whitney Unveils Higher Thrust PurePower Engine" (Press release). Pratt & Whitney. 20 May 2014.
  46. ↑ "PurePower PW1500G Engine" (PDF). Pratt & Whitney.
  47. ↑ "Pratt and Whitney PW1100G Geared Turbofan Engine". The Flying Engineer. 8 Jul 2013.
  48. ↑ "Type Certificate data sheet for PW1100G-JM Series Engines" (PDF). EASA. 23 November 2015.
  49. ↑ "Type Certificate data sheet for PW1500G Series Engines" (PDF). EASA. 5 Dec 2016.
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