View source for Rolls-Royce T406

{{short description|Rolls-Royce North America turboshaft aircraft engine (1986)}}
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{{Use dmy dates|date=August 2017}}
{{Use American English|date=August 2017}}
{{infobox aero engine
 |name= T406 / AE 1107
 |image= File:V-22 main engine closeup.jpg
 |caption= A T406 engine nacelle on a V-22
 |engine_type= [[Turboshaft]]
 |national_origin= United States
 |manufacturer= {{ubl|[[Allison Engine Company]]|[[Rolls-Royce Holdings]]}}
 |first_run= late 1986<ref name="FI19870411" />
 |major_applications= [[Bell Boeing V-22 Osprey]] 
 |number_built= 860 (2018)<ref name="UPI20180601" />
 |developed_from= [[Allison T56]]/[[Allison T701|T701]]
 |variants_with_their_own_articles=
 |developed_into= {{ubl|[[Rolls-Royce AE 2100]]|[[Rolls-Royce AE 3007]]}}
}}

The '''Rolls-Royce T406''' (company designation '''AE 1107''') is a [[turboshaft]] engine developed by [[Allison Engine Company]] (now part of [[Rolls-Royce]]) that powers the [[Bell Boeing V-22 Osprey]] [[tiltrotor]]. The engine delivers {{Convert|6000|shp|kW|abbr=on}}.

== Development ==
In 1982, Detroit Diesel Allison (DDA) prepared a new engine design to enter the [[United States Army]]'s Modern Technology Demonstrator Engine (MTDE) competition, which was expected to be developed into the powerplant for the [[United States Navy]]'s JVX experimental [[tiltrotor]] aircraft program (which would eventually become the [[Bell Boeing V-22 Osprey]]).<ref name="LeyesFleming579580" /> After this engine, which DDA called the Model 580,<ref name="InsideIndy19830114" /> lost the competition to [[Pratt & Whitney]] and [[General Electric]] in 1983, Allison was separated from Detroit Diesel as a separate division within [[General Motors]], and Allison's new management decided to pursue the V-22 engine contract anyway.<ref name="LeyesFleming579580" />

On 24 December 1985, the U.S. Navy selected Allison's engine for full-scale engine development and production on the [[U.S. Marine Corps]]'s V-22 Osprey.<ref name="UPI19851224" /> Before the engine was given its [[United States military aircraft engine designation]] of T406, it was known as the Model 501-M80C.<ref name="AWST19860317" /> The Navy and Allison signed a formal contract on 2&nbsp;May 1986, and the first engine to test ran six months after.<ref name="Brussels1990" />

The T406 is based on the [[Allison T56]] turboprop from the [[Lockheed P-3 Orion|P-3]] and the [[C-130]], with the [[free-turbine engine|free power turbine]] of the [[Allison T701]] turboshaft from the defunct [[Heavy Lift Helicopter program]].<!--<ref name="Flight29jul1989" />-->
It was selected over the [[Pratt & Whitney]] PW3000 and [[General Electric GE27]] competing for the US Army's Modern Technology Demonstrator Engine program.<ref name="Flight29jul1989" /> The T406 began [[flight testing]] on 19 March 1989.<ref name="Chambers1991" />

The T406/AE 1107C Liberty shares a common core with the [[AE&nbsp;3007]] [[turbofan]] and [[AE&nbsp;2100]] [[turboprop]] series of engines, both of which have sold in the thousands of copies.<ref name="RR20170302" /><ref name="2300engines" /> 44–46 percent of parts are common between the T406 and the AE&nbsp;3007, while about 76 percent of parts are common between the T406 and the AE&nbsp;2100.<ref name="Weaknesses" /> In addition, Allison attempted to develop other types of engines based on the T406. In 1988, the company signed a [[memorandum of understanding]] (MoU) with [[Messerschmitt-Bölkow-Blohm]] (MBB) of West Germany and the [[China National Aero-Technology Import & Export Corporation]] (CATIC) to work on a version of the [[MPC 75]] regional aircraft to be powered by a T406-derived [[propfan]].<ref name="FI19880521" /> In 1990, Allison studied a {{cvt|9,000|shp|adj=mid}} propfan powerplant driving {{cvt|8.5|ft|m|adj=mid|diameter}} [[contra-rotating propellers]] to power [[Euroflag]]'s proposed [[military airlift]] aircraft.<ref name="T406Derivatives" /> Also, the MT7 gas turbines that will be used to power the [[Ship-to-Shore Connector]] are a derived design of the T406.<ref name="MM20121101" />

Production continued by [[Rolls-Royce]] after it acquired Allison in 1995 to establish a North American subsidiary. In 2009, the [[Government Accountability Office]] (GAO) found that the engines failed after less than 400&nbsp;hours of service, as compared to the estimated life of 500–600&nbsp;hours.<ref name="MCT20130813" /> Multiple updates to the engine platform in 2012–2013 have increased the lifespan significantly.

In April 2012, the [[United States Department of Defense]] (DoD) ordered 70 AE&nbsp;1107C engines for the Osprey, with options for up to 268 engines.<ref name="rrann" />

Rolls-Royce introduced a "Block&nbsp;3" turbine upgrade, which replaced the old turbine design with sturdier and more efficient components. The upgrade increased engine power by at least 17&nbsp;percent, and the engine achieved a power output of over {{cvt|8,800|shp}} during ground testing.<ref name="FI20140918" /> The Block&nbsp;3 turbine became standard in July 2012 for new production models. By September 2012, all older engines that were undergoing regular maintenance were systematically upgraded to the Block&nbsp;3 turbine.

Engines with a future planned "Block&nbsp;4" upgrade would be expected to deliver nearly {{convert|10,000|hp|kW|abbr=off}}.<ref name="BoostsPower20130916" />

An ongoing problem with the engines was their propensity for surging or stalling with 68 incidents reported between 2003 and October 2016, though this rate had reduced after the introduction of the Block&nbsp;3 engine version. The US Naval Air Systems Command intends to award Rolls-Royce two contracts to examine the effectiveness of proposed reliability improvements. The first is an update to the engine management software that changes how it controls the compressor guide vanes, as internal testing suggested that this could improve the engine's surge margin by 0.8% at sea level and 3% at altitude. The second is the discovery that a temperature sensor at the inlet of the compressor sends incorrect readings leading to 2.5% out of 4% steady power shortfall at the compressors correct rotational speed, again correctable with a software fix. In addition, Bell Boeing is developing an inlet barrier system to reduce the power loss from the engine ingesting dust and sand particles to supplement the engines existing centrifugal based particle separators as they can only do so much to improve the quality of air they receive.<ref name="StallFixes"/>

In October 2021, Bell and Rolls-Royce jointly announced that the [[Bell MV-75]] powerplant would switch from the General Electric T64 turboshaft used on the prototype to a derivative of the 1107C used on the Osprey, which would be named the 1107F. The 1107C is a known element in tiltrotor aircraft with its two decades of prior use which lowers sustainment costs and lowers risk associated with the project, and the 1107F increases the engine's power output from 5,000 to 7,000&nbsp;horsepower.<ref>[https://www.defenseone.com/business/2021/10/bell-picks-rolls-royce-engine-v-280-valor-army-black-hawk-replacement-contest/185953/ Bell Picks Rolls-Royce Engine for V-280 Valor in Army Black Hawk Replacement Contest]</ref>

== Design ==
On the V-22, the T406 engines are housed in wing-tip tilting nacelles, allowing the distinctive flight characteristics of the V-22. For takeoff and landing the nacelles are directed vertically (90° to fuselage), while for forward flight they are rotated parallel to fuselage. The engine has been considered as a cost-effective upgrade for existing heavylift helicopters such as the [[CH-47 Chinook]] and the [[Sikorsky CH-53 Sea Stallion|CH-53]].<ref name="RR-Liberty" />

== Applications ==
* [[Aurora XV-24 LightningStrike]] (1107C)<ref name="Engineer20170407">{{cite news |work=The Engineer |title=DARPA flies scaled-down electric model of VTOL aircraft |url=https://www.theengineer.co.uk/darpa-flies-scaled-down-electric-model-of-vtol-aircraft/ |date=7 April 2017 |first=Stuart |last=Nathan}}</ref>
* [[Bell Boeing V-22 Osprey]] (1107C Liberty)
* [[Bell MV-75]] (1107F)
* US Navy [[Ship-to-Shore Connector]] Landing Craft (MT7)

== Specifications (T406) ==
{{jetspecs
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|ref=
|type= [[Free-turbine turboshaft]]
|length=78.1 in (1,980 mm)
|diameter=34.2 in (890 mm)
|weight=971 lb (440 kg)
|compressor=14-stage high pressure [[axial compressor]], variable geometry vanes in the inlet and the first 5 stages<ref name="Chambers1991" />
|combustion=Diffuser [[annular combustor]] with 16 air-blast fuel nozzles and 2 igniters<ref name="Chambers1991" />
|turbine=2-stage high pressure turbine with air-cooling in the first and second-stage vanes and the first-stage blade; 2-stage shrouded power turbine with uncooled vanes and blades<ref name="Chambers1991" />
|fueltype=
|oilsystem=
|power=6,150 shp (4,586 kW)
|compression=16.7:1
|bypass=
|aircon=
|turbinetemp={{cvt|2,208|F|C F K R|order=out}}<ref name="Brussels1990" />
|specfuelcon=0.426 lb/shp/hr ({{cvt|0.426|lb/hp|disp=number}} kg/kW/hr) SFC,<ref name="jet-engines.net">{{cite web |title=Military Turboshaft/Turboprop Specifications |website=Jet Engine Specification Database | url = http://www.jet-engine.net/miltsspec.html/ |archive-url=https://web.archive.org/web/20210509060114/http://www.jet-engine.net/miltsspec.html/ |archive-date=2021-05-09 | access-date = 4 December 2020 }}</ref> efficiency 32% {{citation needed|date=December 2020}}
|power/weight=6.33 shp/lb (10.4 kW/kg)
}}

== See also ==
{{Portal|Aviation}}
{{Aircontent
|related=
* [[Allison T56]]/[[Allison T701|T701]]
* [[Rolls-Royce AE 2100]]
* [[Rolls-Royce AE 3007]]
|similar engines=
* [[General Electric GE38]]
* [[Lycoming T55]]
|lists=
* [[List of aircraft engines]]
|see also=
}}

== References ==
<references>
<ref name="RR-Liberty">{{cite web |work=[[Rolls-Royce plc]] |title=Taking tilt-rotor operations to new heights |url=https://www.rolls-royce.com/products-and-services/defence/aerospace/rotary/ae-1107c.aspx |access-date=21 June 2020}}</ref>
  <ref name="UPI20180601">{{cite news |work=[[United Press International]] (UPI) |title=Rolls-Royce to deliver V-22 Osprey engines for U.S. military |url=https://www.upi.com/Defense-News/2018/06/01/Rolls-Royce-to-deliver-V-22-Osprey-engines-for-US-military/8321527869627/ |date=1 June 2018 |given=Sam |surname=Howard |department=Defense News}}</ref>
  <ref name="2300engines">{{cite press release |title=Rolls-Royce reaches services contract with USAF for C-130J Fleet |url=https://www.asdnews.com/news/defense/2017/09/20/rollsroyce-reaches-services-contract-with-usaf-c130j-fleet |date=September 20, 2017 |via=ASDNews}}</ref>
  <ref name="RR20170302">{{cite web |work=[[Rolls-Royce plc]] |title=Powering the aircraft of today and tomorrow |url=https://www.rolls-royce.com/products-and-services/defence/aerospace/transport-tanker-patrol-and-tactical/ae-3007.aspx |date=March 2, 2017 |access-date=September 24, 2020}}</ref>
  <ref name="StallFixes">{{cite news |url= https://www.flightglobal.com/news/articles/rolls-royce-studies-two-new-stall-fixes-for-v-22-eng-433309/ |title= Rolls-Royce studies two new stall fixes for V-22 engines |given=Stephen |surname=Trimble |date= 18 January 2017 |work= [[Flightglobal]]}}</ref>
  <ref name="FI20140918">{{cite magazine |issn=0015-3710 |magazine=[[Flight International]] |title=Rolls-Royce touts 'high, hot' performance of upgraded engine for V-22 |url=https://www.flightglobal.com/rolls-royce-touts-high-hot-performance-of-upgraded-engine-for-v-22/114522.article |given=Dan |surname=Parsons |date=18 September 2014 |url-access=limited}}</ref>
  <ref name="BoostsPower20130916">{{cite magazine |magazine=[[Defense News]] |title=Rolls-Royce boosts power for V-22 engines |url=http://www.defensenews.com/article/20130916/DEFREG02/309160009/Rolls-Royce-Boosts-Power-V-22-Engines |date=16 September 2013 |given=Aaron |surname=Mehta |url-status=dead |archive-date=20 September 2013 |archive-url=https://wayback.archive-it.org/all/20130920030937/http://www.defensenews.com/article/20130916/DEFREG02/309160009/Rolls-Royce-Boosts-Power-V-22-Engines}}</ref>
  <ref name="MCT20130813">{{cite news |work=[[Marine Corp Times]] |date=13 August 2013 |given=James K. |surname=Sanborn |url=http://www.marinecorpstimes.com/article/20130813/NEWS04/308130010/DoD-watchdog-audits-Osprey-readiness |title=Pentagon watchdog to release classified audit on V-22 Osprey |archive-url=https://web.archive.org/web/20130817095918/http://www.marinecorpstimes.com/article/20130813/NEWS04/308130010/DoD-watchdog-audits-Osprey-readiness |archive-date=17 August 2013 |url-status=dead}}</ref>
  <ref name="MM20121101">{{cite magazine |issn=0024-9211 |magazine=Machinery Market |date=1 November 2012 |title=New contract win for Rolls-Royce |url=https://www.machinery-market.co.uk/news/1872/New-contract-win-for-Rolls-Royce |access-date=5 January 2022}}</ref>
  <ref name="rrann">[http://www.aero-news.net/index.cfm?do=main.textpost&id=0cfbc9ef-21b7-4625-8a1c-b69a3800f80e "Rolls-Royce Awarded $598 M V-22 Engine Contract"] ''AeroNews'', 24 April 2012. Retrieved 24 April 2012.</ref>
  <ref name="LeyesFleming579580">{{harvnb|Leyes II|Fleming|1999|pp=[{{GBurl|V0SnFt8JGokC|p=579}} 579]-[{{GBurl|V0SnFt8JGokC|p=580}} 580]}}</ref>
  <ref name="Weaknesses">{{cite report |author=[[United States General Accounting Office]] (GAO) |title=Defense depot maintenance: Weaknesses in the T406 engine logistics support decision methodology |url=https://www.gao.gov/assets/230/226352.pdf |date=September 14, 1998 |oclc=40045078}}</ref>
  <ref name="Chambers1991">{{cite conference |issn=0148-7191 |title=Turboshaft engine development for commercial tiltrotor aircraft |given=Howard A. |surname=Chambers |pages=140–151 |publication-date=1991 |volume=100 |book-title=SAE Transactions Journal of Aerospace |series=SAE Technical Paper Series |conference=1991 SAE General, Corporate, & Regional Aviation Meeting & Exposition |location=Wichita, Kansas, U.S.A. |date=April 9–11, 1991 |jstor=44547587 |doi=10.4271/911017 |oclc=7851143859}}</ref>
  <ref name="T406Derivatives">{{cite conference |title=Derivative T406 based turbofans for advanced trainers |url=https://asmedigitalcollection.asme.org/GT/proceedings-pdf/GT1990/79054/V002T02A018/2399351/v002t02a018-90-gt-243.pdf |conference=Gas Turbine and Aeroengine Congress and Exposition |date=June 11–14, 1990 |location=Brussels, Belgium |given1=R.E. |surname1=Riffel |given2=T.F. |surname2=McKain |oclc=8518921090 |doi=10.1115/90-GT-243|doi-access=free }}</ref>
  <ref name="Brussels1990">{{cite conference |url=https://asmedigitalcollection.asme.org/GT/proceedings-pdf/GT1990/79054/V002T02A020/2399201/v002t02a020-90-gt-245.pdf |title=T406 engine development program |publisher=[[American Society of Mechanical Engineers]] (ASME) |date=11–14 June 1990 |doi=10.1115/90-GT-245 |given1=John R. |surname1=Arvin |given2=Mark E. |surname2=Bowman |conference=Gas Turbine and Aeroengine Congress and Exposition |location=Brussels, Belgium|doi-access=free }}</ref>
  <ref name="Flight29jul1989">{{cite magazine |url= https://www.flightglobal.com/pdfarchive/view/1989/1989%20-%202327.html |title= Power derived |date= 29 July 1989 |magazine= Flight International}}</ref>
  <ref name="FI19880521">{{cite magazine |magazine=[[Flight International]] |title=Allison joins MBB/China propfan project |url=https://www.flightglobal.com/FlightPDFArchive/1988/1988%20-%201348.PDF |page=14 |publication-date=May 21, 1988 |url-status=dead |archive-date=April 29, 2016 |archive-url=https://web.archive.org/web/20160429014021/https://www.flightglobal.com/FlightPDFArchive/1988/1988%20-%201348.PDF}}</ref>
  <ref name="FI19870411">{{cite magazine |title= Taking the turboshaft honours |date= 11 April 1987 |url= https://www.flightglobal.com/pdfarchive/view/1987/1987%20-%200092.html |magazine= Flight International}}</ref>
  <ref name="AWST19860317">{{cite magazine |issn=0005-2175 |magazine=[[Aviation Week & Space Technology]] |title=Allison cites low-cost, low-risk design approach as key to V-22 engine award |url=http://digitalcollections.library.cmu.edu/awweb/awarchive?type=file&item=710856 |format=PDF |publication-date=March 17, 1986 |location=Indianapolis, Indiana, USA |pages=52, 57 |volume=124}}</ref>
  <ref name="UPI19851224">{{cite news |work=[[UPI]] |title=A General Motors Corp. division has been selected to... |url=https://www.upi.com/Archives/1985/12/24/A-General-Motors-Corp-division-has-been-selected-to/9859504248400/ |date=24 December 1985 |given=Richard C. |surname=Gross}}</ref>
  <ref name="InsideIndy19830114">{{cite newsletter |work=Inside Indy Operations Newsletter |title=Future contracts - Job impact status clarified |url=https://indianamemory.contentdm.oclc.org/digital/collection/AT/id/7654 |editor-first=John |editor-last=McCardle |publication-date=14 January 1983 |volume=3 |number=1 |edition=Speedway |publisher=[[Detroit Diesel Allison]]}}</ref>
</references>

== Further reading ==
* {{cite book |last=Leyes II |first=Richard A. |first2=William A. |last2=Fleming |title=The history of North American small gas turbine aircraft engines |publisher=Smithsonian Institution |location=Washington, DC |year=1999 |isbn=1-56347-332-1 |url={{GBurl|V0SnFt8JGokC}} |oclc=247550535}}
* {{cite conference |title=Common core development approach for Allison T406/AE family of turboshaft, turboprop, and turbofan engines |url=http://www.icas.org/ICAS_ARCHIVE/ICAS1998/PAPERS/563.PDF |given=David B. |surname=Newill |conference=ICAS Congress |date=September 13–18, 1998 |location=Melbourne, Victoria, Australia |edition=21st |conference-url=https://www.icas.org/ICAS_ARCHIVE/ICAS1998/index.html |isbn=978-1-56347-287-9 |oclc=43888882}}
* {{cite conference |title=Gas turbine engine development partnerships |work=SAE Technical Papers |pages=119–132 |given=Jim |surname=Korn |date=November 13, 1987 |doi=10.4271/872410 |publisher=SAE International |oclc=5817974566 |issn=0148-7191 |conference=International Pacific Air and Space Technology Conference and Exposition |location=Melbourne, Australia}}

== External links ==
{{Commons category|Rolls-Royce AE 1107C (T406)}}
* [https://www.rolls-royce.com/products-and-services/defence/aerospace/rotary/ae-1107c.aspx#/ AE 1107C-Liberty at Rolls-Royce site]
* [https://web.archive.org/web/20100816030624/http://www.rolls-royce.com/Images/AE1107C_tcm92-6702.pdf AE 1107C-Liberty Fact Sheet]
* {{cite report |title=Type certificate data sheet no. E00008CH |url=https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/d4e6e669831fa5ff8525676200471038/$FILE/E00008ch.pdf |number=1 |publication-date=April 2, 1999 |publisher=Department of Transportation ([[USDOT]]), [[Federal Aviation Administration]] (FAA)}}
* {{cite magazine |issn=0025-3170 |magazine=[[Marine Corps Gazette]] |title=Allison introduces new technologies for the V-22 Osprey |url={{GBurl|Ypm5QWIKtCAC|pg=RA1-PA9}} |publication-date=February 1988 |page=9 |author=Allison |volume=72 |number=2}}

{{Allison aeroengines}}
{{Rolls-Royce plc aeroengines}}
{{USAF gas turbine engines}}

{{Aeroengine-specs}}

[[Category:1980s turboshaft engines]]
[[Category:Rolls-Royce aircraft gas turbine engines|T406]]