Yakovlev Yak-46

{{Short description|Cancelled Soviet aircraft type}} {{Infobox aircraft |name= Yak-46 |image= |caption= |type=Airliner |national_origin=Soviet Union / Russia |manufacturer= |designer= Yakovlev Design Bureau |first_flight= |introduction= |retired= |status=Cancelled |primary_user= |more_users=  |produced=  |number_built= 0 |program cost=  |unit cost=  |developed_from= Yakovlev Yak-42 | variants= }}

The '''Yakovlev Yak-46''' was a proposed aircraft design based on the Yak-42 with two contra-rotating propellers on the propfan located at the rear. The specification of the Samara turbofans was in the 11,000 kg (24,250 lb) thrust range.<ref name="GunstonGordon"/> Though proposed in the 1990s, production of the Yak-46 never commenced.<ref name="USITC"/>

==Design and development== At the 1987 Paris Air Show, the Soviet Union displayed scale models of several aircraft in development,<ref name="SovietDisplays"/> including a 150-seat aircraft powered by two pusher propfans mounted on the rear fuselage.<ref name="UpgradeCivilMilitary"/> This aircraft was unnamed at the time, but the Soviets disclosed that the Yakovlev Design Bureau was developing the aircraft.<ref name="UpgradeCivilMilitary"/> Later in 1987, the Soviet civil aviation minister noted that Yakovlev was building a twin-propfan airliner based on its Yak-42 model.<ref name="Gorlov1987"/> In 1989, Yakovlev planned to test the D-236 propfan engine from the Ivchenko-Progress engine design bureau (also known as Progress, Lotarev, Muravchenko, ZMKB, and Zaporozhye) in flight on a Yak-42 testbed aircraft by the end of the year.<ref name="ExperimentalTractor"/>

Yakovlev revealed details in early 1990 about Yakovlev's propfan design, which was given the name of Yak-46 and planned to enter service in 1997.<ref name="FI19900410"/> The Yak-46 and the Yak-42M, a {{convert|4|m|ft mm in|abbr=off|adj=mid|stretched derivative}} of the Yak-42 that would enter service in 1994, would have fly-by-wire (FBW) controls, an electronic flight instrument system (EFIS), a supercritical airfoil wing of added aspect ratio, span, and sweep, seating capacity of 150 passengers or more, and new engines with thrust reversal capability. However, the Yak-46 would have two unshrouded propfan engines mounted on the aft fuselage, instead of the Yak-42 and Yak-42M's three aft-mounted turbofan engines (that includes one attached to the vertical stabilizer). Yakovlev also proposed an unnamed interim derivative situated between the Yak-42M and the Yak-46, which would be powered by two underwing engines based on the contra-rotating, integrated, shrouded propfan (CRISP) engine concept. Since this derivative required greater airframe changes, Yakovlev was less sure of its eventual production.

The Yak-46 would hold 150-162 seats in a six-abreast, single-aisle configuration, fly as far as {{convert|1540|nmi|km mi}}, cruise at a speed of {{convert|445|to|460|kn|km/h|round=50}}, and be powered by two Lotarev D-27 propfan engines. The {{convert|3.8|m|ft mm in|adj=mid|diameter}} propfan engines would have contra-rotating propellers with eight blades in front and six blades in back, have a thrust specific fuel consumption of {{cvt|0.44|tsfc|si tsfc}}, and deliver {{convert|9700|kW|hp}}, resulting in a thrust of {{cvt|11.2|tf|kgf lbf kN|sigfig=3|order=out}}. The fuel consumption per available seat kilometer of the Yak-46 was {{convert|13.8|g/km|oz/mi|abbr=off}} per seat. This value compared to {{cvt|14.5|g/km|oz/mi}} for the Yak-46's underwing engine alternative and {{cvt|21|g/km|oz/mi}} for the Yak-42M, which was already 35-40% more efficient than the Yak-42. At the time, airline interest but no orders were reported for the Yak-46, but Yakovlev was negotiating to sell 200 Yak-42M planes to Aeroflot,<ref name="YakovlevStrikesBack"/> which was then the world's largest airline.<ref name="CatchingUp"/>

By October 1990, the two versions of the Yak-46 were in competition with the 102-126 seat Tupolev Tu-334, which like the higher-capacity Yak-46 had an interim turbofan version and a final propfan version, to replace hundreds of aging Tupolev Tu-134 airliners at Aeroflot. To prepare for Yak-46 development, Yakovlev created a joint venture with Ivchenko Progress and the Soviet Ministry of Civil Aviation. Aeroflot would help fund a prototype, which would be built starting early in 1991 if the Yak-46 were selected. Annual production would eventually be as high as 100 airliners and would run through 2005.<ref name="Tu134Replacement"/>

On March 15, 1991, Yakovlev finally began flight tests of one D-236 propfan engine on a Yak-42E-LL aircraft testbed, making it the first propfan flight test program led by an individual Soviet aircraft design bureau.<ref name="YakovlevTakesLead"/> The testbed appeared on static display at the 1991 Paris Air Show in June.<ref name="YakovlevDisplaysTestbed"/> Like the D-27 engine, the D-236 was a contra-rotating system with an eight-bladed front propeller and a six-bladed back propeller. It had a fan diameter of {{cvt|4.2|m|ft mm in}}, a power rating of {{cvt|8195|kW|hp}},<ref name="Yak42D236"/> and a thrust rating of {{cvt|10.5|–|11|tf|kgf lbf kN|order=out}}. The testbed engine was limited to a smaller thrust, though, because the D-236 was more powerful than the Lotarev D-36 engine that it replaced.<ref name="EagleEyeFleet"/>

[[File:Yakovlev Yak-42LL, Aeroflot AN0916963.jpg|thumb|left|To support the development of its Yak-46 concept, Yakovlev flew a Yak-42E-LL testbed aircraft powered in part by a Progress D-236 experimental propfan engine.]]

Meanwhile, conflicting reports appeared about the Yak-46 power plant: one article stated that the D-236 would be the eventual engine,<ref name="CommercialEngines1991"/> but another article said Yakovlev was deciding between a gearless unducted fan, which would yield a fuel consumption of {{cvt|12|g/km|oz/mi}}, and a less-efficient, but now considered more realistic, ducted fan with an ultra-high bypass ratio between 20 and 27.<ref name="YakovlevTakesLead"/> In August, a report stated that the initial version of the Yak-46, now named the Yak-46-1, would have two Progress underwing power plants resembling the International Aero Engines (IAE) SuperFan engine, while the follow-up version, called the Yak-46-2, would again be aft fuselage-mounted D-27 engines.<ref name="SovietCoup"/> A Soviet aviation publication named the initial engine as the Progress D-627, a quiet, super-high bypass ratio turbofan.<ref name="FBIS_19920305"/> Derived from the D-27, the D-627 had ducted, contra-rotating fans and used a differential gearbox.<ref name="Threshold"/> The D-627 had a takeoff thrust of {{cvt|11000|kgf|lbf kN}}; its thrust specific fuel consumption (TSFC) at cruise would not exceed {{cvt|0.5|tsfc|si tsfc}} at Mach 0.8 and {{cvt|11000|m|ft}} altitude, equivalent to a speed of {{cvt|0.8|Mach|altitude_m=11000|kn km/h mi/h|order=out|0}}; and the Yak-46's per-passenger fuel consumption with the D-627 would be {{cvt|15.5|g/km|oz/mi}}. The subsequent version of the Yak-46 would have the same characteristics and performance outlined for the D-27 earlier, but its cruise TSFC after losses would be {{cvt|0.47|tsfc|si tsfc}} at {{cvt|850|km/h|kn km/h mi/h|order=out}} speed. In addition, the Yak-46 would have a planned service life of 60,000 hours, based on an annual average flying time of 3,000 hours.<ref name="FBIS_19920305"/> Yakovlev was constructing a wooden mockup of the Yak-46 as of November 1991.<ref name="DBSurvival"/> By August 1992, it was planning for co-production of the aircraft in South Africa.<ref name="DualCarriageway"/>

As of March 1993, Yakovlev had received one order to develop the Yak-46, which temporarily saved the firm from bankruptcy.<ref name="PrivatizationProblems"/> In mid-1994, the Progress engine design bureau was looking to create a turbojet derivative of its D-27 to use on the Yak-46.<ref name="RussianTurmoil"/> Later that year, it was reported that the Yak-46 would use two Progress D-727 high-bypass turbofan engines, without mention of a propfan aircraft version.<ref name="Airliners1994"/> In 1996, though, another airliner census still described a Yak-46-1 version with D-727 underwing engines followed by a Yak-46-2 with D-27 aft-mounted engines in a T-tail empennage configuration. Because of engine development issues, neither of the planes would fly before the year 2000.<ref name="Airliners1996"/>

==Specifications== {{Aircraft specs |ref=Grazhdanskaya Aviatsiya (Civil Aviation), September 1991.<ref name="FBIS_19920305"/> |prime units?=met  |genhide=

|crew=2–3 |capacity=150 |length m=41<ref name="taylor"/> |length ft= |length in= |length note= |span m=35.5<ref name="taylor"/> |span ft= |span in= |span note= |upper span m= |upper span ft= |upper span in= |upper span note= |mid span m= |mid span ft= |mid span in= |mid span note= |lower span m= |lower span ft= |lower span in= |lower span note= |swept m= |swept ft= |swept in= |swept note= |dia m=3.8<ref name="AviationAstronautics199506"/> |dia ft= |dia in= |dia note=fuselage |width m= |width ft= |width in= |width note= |height m=11<ref name="AviationAstronautics199506"/> |height ft= |height in= |height note= |wing area sqm=120 |wing area sqft= |wing area note= |swept area sqm= |swept area sqft= |swept area note= |volume m3= |volume ft3= |volume note= |aspect ratio=10.5 |airfoil= |empty weight kg=37300<ref name="taylor"/> |empty weight lb= |empty weight note= |gross weight kg= |gross weight lb= |gross weight note= |max takeoff weight kg=61300 |max takeoff weight lb= |max takeoff weight note= |lift kg= |lift lb= |lift note= |more general=  |eng1 number=2 |eng1 name=Ivchenko Progress D-27 |eng1 type=propfan |eng1 kw= |eng1 hp= |eng1 kn= |eng1 lbf={{cvt|11200|kgf|lbf|disp=number}} |eng1 note= at takeoff |power original= |thrust original= |eng1 kn-ab= |eng1 lbf-ab=

|more performance=

}}

==See also== {{Portal|Aviation}} * Antonov An-180 * Boeing 7J7 * McDonnell Douglas MD-94X * MPC 75 * Tupolev Tu-334

==References== ===Citations=== {{Reflist|30em|refs= <ref name="USITC">{{cite book| author = U.S. International Trade Commission| title = Global Competitiveness of U.S. Advanced Technology Manufacturing Industries| publisher = DIANE| isbn = 978-1-4578-2609-2 }}</ref>

<ref name="Threshold">{{cite magazine |url=http://engine.aviaport.ru/issues/71/page20.html |pages=20–22|year=2010 |given1=Igor Fedorovich |surname1=Kravchenko |given2=Igor Yuvenalievich |surname2=Stepanov |given3=Alexander Nikolaevich |surname3=Khustochka |title=ГП 'Ивченко-Прогресс': на пороге создания двигателей нового поколения |trans-title=GP 'Ivchenko-Progress': On the threshold of creating engines of new generation |language=Russian |magazine=Dvigatel (Engine)|volume=5 |issue=71 }}</ref> <ref name="EagleEyeFleet">{{cite magazine |url=http://www.ozakaz.ru/index.php/articles/15032008/229-n2011-03-28-0338 |language=Russian |title=ОРЛИНЫЙ ГЛАЗ ФЛОТА Самолет радиолокационного дозора и наведения Як-44Э |trans-title=Eagle eye of the fleet: Aircraft radar patrol and guidance Yak-44E |date=March 2008 |number=18 |given=Vadim |surname=Abidin |magazine=Oboronnyy Zakaz (Defense Order) |via=A.S. Yakovlev design bureau, Kryl'ia Rodiny (Wings of the Motherland) magazine |archive-url=https://web.archive.org/web/20190518064427/http://www.yak.ru/DOCS/Yak-44E.pdf |url-status=live |archive-date=May 18, 2019}}</ref> <ref name="GunstonGordon">{{cite book |given1=Bill |surname1=Gunston |given2=Yefim |surname2=Gordon |title=Yakovlev aircraft since 1924 |year=1997 |publisher=US Naval Institute Press |isbn=978-1-55750-978-9 |oclc=636698350}}</ref> <ref name="Airliners1996">{{cite magazine |issn=0015-3710 |magazine=Flight International |title=Airliners of the world |url=https://www.flightglobal.com/pdfarchive/view/1996/1996%20-%203242.html |page=70 |date=December 4–10, 1996 |volume=150 |number=4552}}</ref> <ref name="taylor">{{cite book |surname=Taylor |given=Michael J. H. |title=Brassey's World Aircraft & Systems Directory |location=London, England, UK |publisher=Brassey's |url=https://archive.org/details/brasseysworldair0000unse/page/242 |pages=[https://archive.org/details/brasseysworldair0000unse/page/242 242–243] |year=1996 |isbn=1-85753-198-1 |oclc=33079608}}</ref> <ref name="AviationAstronautics199506">{{cite magazine |issn=0373-9821 |script-work=ru:Авиация и космонавтика |trans-work=Aviation and astronautics |script-title=ru:КРАТКИЙ СПРАВОЧНИК ПО РОССИЙСКИМ И УКРАИНСКИМ САМОЛЕТАМ И ВЕРТОЛЕТАМ |trans-title=Quick guide to Russian and Ukrainian aircraft and helicopters |url=https://e-libra.ru/read/224921-aviaciya-i-kosmonavtika-1995-06.html#1649010862 |language=Russian |publication-date=June 1995 |year=1995 |number=6|magazine=Aviatsiia I Kosmonavtika -Moskva- }}</ref> <ref name="Airliners1994">{{cite magazine |issn=0015-3710 |magazine=Flight International |title=Commercial airliners directory |url=https://www.flightglobal.com/FlightPDFArchive/1994/1994%20-%202621.PDF |date=October 26 – November 1, 1994 |page=54 |url-status=dead |archive-date=November 25, 2019 |archive-url=https://web.archive.org/web/20191125063154/https://www.flightglobal.com/FlightPDFArchive/1994/1994%20-%202621.PDF}}</ref> <ref name="RussianTurmoil">{{cite magazine |issn=1423-3215 |magazine=Interavia |title=Russian engine industry in turmoil |date=June 1994 |publisher=Aerospace Media Publishing |given=Michael |surname=Taverna |pages=26–28 |department=Finance, Markets & Industry |location=Moscow, Russia |volume=49 |number=579 }}</ref> <ref name="PrivatizationProblems">{{cite report |work=Central Eurasia |series=FBIS Report |translator=Foreign Broadcast Information Service |title=Problems of privatization of aircraft companies viewed |url=https://hdl.handle.net/2027/inu.30000028466971?urlappend=%3Bseq=525 |department=Russia: Economic and Social Affairs |pages=67–69 |publication-date=April 10, 1993 |date=March 15–21, 1993 |given1=Natalya |surname1=Kalinichenko |given2=Aleksandr |surname2=Privalov |given3=Pavel |surname3=Krizhevskiy |volume=FBIS-USR-93-045 |publisher=Kommersant |hdl=2027/inu.30000028466971}}</ref> <ref name="DualCarriageway">{{cite magazine |issn=0015-3710 |magazine=Flight International |title=Dual carriageway |given=Alexander |surname=Velovich |pages=57+ |date=August 12, 1992 |volume=142 |number=4331 |id={{Gale|A12511834}}}}</ref> <ref name="DBSurvival">{{cite magazine |issn=0005-2175 |magazine=Aviation Week & Space Technology |title=Yakovlev banks on new transports to ensure design bureau's survival |url=https://archive.aviationweek.com/issue/19911118/#!&pid=50 |url-access=subscription |pages=50–51 |date=November 18, 1991 |department=Soviet Aerospace in Turmoil |location=Moscow, USSR |volume=135 |number=20}}</ref> <ref name="FBIS_19920305">{{cite report |work=Central Eurasia: Baltic and Eurasian States: Interstate affairs |series=FBIS Report |translator=Foreign Broadcast Information Service |title=Yak-46 airliner profiled |url=https://hdl.handle.net/2027/inu.30000028648115?urlappend=%3Bseq=368 |department=Transportation |pages=94–96 |publication-date=March 5, 1992 |date=September 1991 |volume=FBIS-USR-92-023 |publisher=Grazhdanskaya Aviatsiya (Civil Aviation) |hdl=2027/inu.30000028648115}}</ref> <ref name="SovietCoup">{{cite magazine |issn=0005-2175 |magazine=Aviation Week & Space Technology |title=Coup hits as Soviet aerospace industry fights funding and operational problems |url=https://archive.aviationweek.com/issue/19910826/#!&pid=24 |url-access=subscription |pages=24–25 |date=August 26, 1991 |given=Jeffrey M. |surname=Lenorovitz |department=Crisis in the Soviet Union |location=Moscow, Leningrad, and Kiev, USSR |volume=135 |number=8}}</ref> <ref name="YakovlevDisplaysTestbed">{{cite magazine |issn=0005-2175 |magazine=Aviation Week & Space Technology |title=Yakovlev displays propfan testbed at Paris Air Show |date=July 1, 1991 |page=44 |url=https://aviationweek.com/site-files/aviationweek.com/files/uploads/2015/05/aw_paris_1991.pdf |location=Le Bourget, France |department=Paris Air Show |volume=134 |number=26 |url-status=dead |archive-date=November 25, 2019 |archive-url=https://web.archive.org/web/20191125062133/https://aviationweek.com/site-files/aviationweek.com/files/uploads/2015/05/aw_paris_1991.pdf}}</ref> <ref name="Yak42D236">{{cite magazine |issn=0015-3710 |magazine=Flight International |title=Yak propfan pops into Paris |url=https://www.flightglobal.com/FlightPDFArchive/1991/1991%20-%201738.PDF |date=June 26 – July 2, 1991 |department=Paris Show Report |page=16 |volume=140 |number=4272 |url-status=dead |archive-date=November 25, 2019 |archive-url=https://web.archive.org/web/20191125061922/https://www.flightglobal.com/FlightPDFArchive/1991/1991%20-%201738.PDF}}</ref> <ref name="CatchingUp">{{cite magazine |title=Catching up |date=May 22–28, 1991 |magazine=Flight International |id={{Gale|A10813969}} |url=https://www.flightglobal.com/FlightPDFArchive/1991/1991%20-%201279.PDF |department=Comment |page=3 |volume=139 |number=4267 |issn=0015-3710 |url-status=dead |archive-date=November 25, 2019 |archive-url=https://web.archive.org/web/20191125063128/https://www.flightglobal.com/FlightPDFArchive/1991/1991%20-%201279.PDF}}</ref> <ref name="CommercialEngines1991">{{cite magazine |issn=0015-3710 |magazine=Flight International |title=Commercial engines |url=https://www.flightglobal.com/pdfarchive/view/1991/1991%20-%201299.html |given=Guy |surname=Norris |date=May 22–28, 1991 |pages=23, 26 |volume=139 |number=4267}}</ref> <ref name="YakovlevTakesLead">{{cite magazine |title=Yakovlev takes propfan lead: While development of fuel-saving propfan engines languishes in the West, work continues in the Soviet Union where recent fuel shortages have underscored the need for new engine technology |given=Boris |surname=Rybak |date=May 22–28, 1991 |id={{Gale|A10813997}} |magazine=Flight International |url=https://www.flightglobal.com/pdfarchive/view/1991/1991%20-%201303.html |department=Commercial Engines |pages=27–28 |volume=139 |number=4267 |issn=0015-3710}}</ref> <ref name="Tu134Replacement">{{cite magazine |issn=0015-3710 |magazine=Flight International |title=TU-134 replacement decision due |id={{Gale|A8987476}} |url=https://www.flightglobal.com/flightpdfarchive/1990/1990%20-%203108.pdf |page=28 |department=Moscow Aerospace '90 |date=October 10–16, 1990 |volume=138 |number=4237 |url-status=dead |archive-date=November 25, 2019 |archive-url=https://web.archive.org/web/20191125063128/https://www.flightglobal.com/flightpdfarchive/1990/1990%20-%203108.pdf}}</ref> <ref name="YakovlevStrikesBack">{{cite magazine |title=Yakovlev strikes back: Propfan and other high-technology derivatives of the Yak-42 airliner (NATO codename Clobber) are planned |given=Alan |surname=Postlethwaite |date=May 9–15, 1990 |magazine=Flight International |id={{Gale|A8494186}} |url=https://www.flightglobal.com/pdfarchive/view/1990/1990%20-%201347.html |pages=61–62, 65–66 |volume=137 |number=4215 |issn=0015-3710}}</ref> <ref name="FI19900410">{{cite magazine |issn=0015-3710 |magazine=Flight International |title=Yakolev plans propfan Yak-42 derivative |url=https://www.flightglobal.com/flightpdfarchive/1990/1990%20-%200974.pdf |department=Technical: Air Transport |page=18 |date=April 4–10, 1990 |volume=137 |number=4210 |url-status=dead |archive-date=November 25, 2019 |archive-url=https://web.archive.org/web/20191125061939/https://www.flightglobal.com/flightpdfarchive/1990/1990%20-%200974.pdf}}</ref> <ref name="ExperimentalTractor">{{cite magazine |issn=0005-2175 |magazine=Aviation Week & Space Technology |title=Experimental tractor propfan flight tested on Ilyushin Il-76 |url-access=subscription |page=51 |url=http://archive.aviationweek.com/issue/19890605/#!&pid=51 |date=June 5, 1989 |given=Donald E. |surname=Fink |department=Soviet Aerospace Industry |location=Zaporozhye, USSR |volume=130 |number=23}}</ref> <ref name="Gorlov1987">{{cite magazine |issn=0015-3710 |magazine=Flight International |title=Soviets doubt new Il-96-300 |url=https://www.flightglobal.com/FlightPDFArchive/1987/1987%20-%201623.PDF |department=Air Transport |page=5 |date=September 5, 1987 |volume=132 |number=4078 |location=Moscow, Russia, Soviet Union |url-status=dead |archive-date=November 25, 2019 |archive-url=https://web.archive.org/web/20191125061944/https://www.flightglobal.com/FlightPDFArchive/1987/1987%20-%201623.PDF}}</ref> <ref name="UpgradeCivilMilitary">{{cite magazine |magazine=Aviation Week & Space Technology |title=Soviets developing advanced aircraft to upgrade civil, military air fleets |url=https://aviationweek.com/site-files/aviationweek.com/files/uploads/2015/05/aw_paris_1987.pdf |pages=20–22 |date=June 22, 1987 |department=Paris Air Show |volume=126 |number=25 |location=Le Bourget, France |url-status=dead |archive-date=November 25, 2019 |archive-url=https://web.archive.org/web/20191125063126/https://aviationweek.com/site-files/aviationweek.com/files/uploads/2015/05/aw_paris_1987.pdf#page=3}}</ref> <ref name="SovietDisplays">{{cite magazine |magazine=Aviation Week & Space Technology |title=Soviet Union displays advanced transport designs |url=https://archive.aviationweek.com/issue/19870615/#!&pid=64 |pages=64–65 |date=June 15, 1987 |department=Paris Air Show |volume=126 |number=24 |url-access=subscription}}</ref> }}

===Bibliography=== {{refbegin}} * {{cite magazine |issn=0015-3710 |magazine=Flight International |title=Opening doors: The Soviet aerospace industry is in transition as military cuts hit and its factories start producing consumer goods. |url=https://www.flightglobal.com/pdfarchive/view/1990/1990%20-%201136.html |given=Alan |surname=Postlethwaite |pages=28–31 |date=April 18–24, 1990 |volume=137 |number=4212}} {{refend}}

==External links== {{refbegin}} * {{cite AV media |title=Легенда Боинга. Фильм II. Уроки Боинга. |url=https://video.sibnet.ru/video1174039-Legenda_Boinga__Film_II__Uroki_Boinga_/ |trans-title=The legend of Boeing. Part II: The lessons of Boeing. |year=1991 |language=Russian |medium=Television production |time=38:04 |via=sibnet.ru |people=Salnikov, Yuri Petrovich (Director) |others=Interview with Yakovlev general designer A. Dondukov}} {{refend}}

Yak-046 Category:Propfan-powered aircraft