{{Short description|1950s Soviet turboprop aircraft engine}} {{infobox aero engine |name= NK-12 |image= File:Kuznetsov NK-12M turboprop on Tu-95.jpg |caption= NK-12M Turboprop engine on a Tu-95 at RIAT Fairford 1993 |engine_type= Turboprop |national_origin= Soviet Union |manufacturer= Kuznetsov Design Bureau |first_run= October 1952 |major_applications= {{ubl | Antonov An-22 | Tupolev Tu-95 | Tupolev Tu-114 | Tupolev Tu-142 }} |number_built= |developed_from= |variants_with_their_own_articles= |developed_into= }} The exhaust ports of a NK-12 in an outboard nacelle on a Tu-95|thumb

The '''Kuznetsov NK-12''' is a Soviet turboprop engine of the 1950s, designed by the Kuznetsov design bureau. The NK-12 drives two large four-bladed contra-rotating propellers, {{cvt|5.6|m}} diameter (NK-12MA), and {{cvt|6.2|m}} diameter (NK-12MV). It is the most powerful turboprop engine to enter service.

==Design and development==

The design that eventually became the NK-12 turboprop was developed after World War II by a team of Soviet scientists and imprisoned German engineers as part of Operation Osoaviakhim, led by Ferdinand Brandner, who had worked for Junkers previously; the design bureau was headed by chief engineer Nikolai D. Kuznetsov. Thus, the NK-12 design evolved from late-war German turboprop studies. This started with the postwar development of the wartime Jumo 022 turboprop design that was designed to develop {{cvt|6000|shp|lk=in}}, weighing {{cvt|3000|kg}}. The effort continued with a {{cvt|5000|shp}}, weighing {{cvt|1700|kg}}, completed by 1947. Evolution to the TV-12 {{cvt|12000|shp}} engine required extensive use of new Soviet-developed alloys and was completed in 1951.<!--dead link which will NOT be recoverable<ref>[http://www.janes.com/articles/Janes-Aero-Engines/Kuznetsov-NK-12-Russian-Federation.html Kuznetsov NK-12 (Russian Federation) - Jane's Aero-Engines]</ref>-->

The NK-12 is the most powerful turboprop engine to enter service, ahead of the Europrop TP400 (in 2005). Another engine of similar size, the Pratt & Whitney T57 with {{cvt|15000|shp}} and {{cvt|5000|lbf|kN}} jet thrust, ran 3,100 hours before being cancelled in 1957.<ref name="Connors">{{cite book |last1=Connors |first1=J. |title=The engines of Pratt & Whitney : a technical history |date=2010 |publisher=American Institute of Aeronautics and Astronautics |isbn=978-1-60086-711-8 |page=294}}</ref><ref name="Mulready">{{cite book |last1=Mulready |first1=Dick |title=Advanced engine development at Pratt & Whitney : the inside story of eight special projects, 1946-1971 |date=2001 |publisher=Society of Automotive Engineers |isbn=9780768006643 |page=20}}</ref> The NK-12 powers the Tupolev Tu-95 bomber and its derivatives such as the Tu-142 maritime patrol aircraft and the Tupolev Tu-114 airliner (with NK-12MV), which still holds the title of the world's fastest propeller-driven aircraft despite being retired from service in 1991. It also powered the Antonov An-22 Antei (with NK-12MA), the world's largest aircraft at the time, and several types of amphibious assault craft, such as the A-90 Orlyonok "Ekranoplan".

The engine has a 14-stage axial-flow compressor, producing pressure ratios between 9:1 and 13:1 depending on altitude, with variable inlet guide vanes and blow-off valves for engine operability. The combustion system used is a cannular-type: each flame tube is centrally mounted on a downstream injector that ends in an annular secondary region. The contra-rotating propellers and compressor are driven by the five-stage axial turbine. Mass flow is 65&nbsp;kg (143&nbsp;lb) per second.<ref name="airpages">{{cite web |title=Creation of the TV-2 (NK-12) turboprop engine |url=http://www.airpages.ru/eng/ru/troph3.shtml |website=www.airpages.ru |accessdate=22 March 2019}}</ref>

==Variants== thumb|NК-12МV Data from Alexandrov

;NK-12:{{cvt|9300|kW|hp|order=flip}}, initial development model, used on the Tupolev Tu-95 and Tupolev Tu-116 ;NK-12M:{{cvt|8950|kW|hp|order=flip}}, used on the Tupolev Tu-114 ;NK-12MV:{{cvt|11033|kW|hp|order=flip}},<ref name="MV">{{cite encyclopedia |title=NK-12MV |publisher=Ulyanovsk Higher Aviation School of Civil Aviation |url=http://www.uvauga-dvig.narod.ru/nk-12mv.pdf |access-date=August 21, 2019 |series=Domestic Aerospace Engineering |page=18 |language=Russian}}</ref> {{cvt|5.6|m|ftin cm in|adj=mid|diameter|0}} AV-60 propellers, used on the Tupolev Tu-95, Tupolev Tu-126, and Tupolev Tu-142 ;NK-12MA:{{cvt|11186|kW|hp|order=flip}}, {{cvt|6.2|m|ftin cm in|adj=mid|diameter|0}} AV-90 propellers, used on the Antonov An-22 ;NK-12MK:{{cvt|11033|kW|hp|order=flip}}, {{cvt|5.6|m|ftin cm in|adj=mid|diameter|0}} propellers, built with corrosion-resistant materials, used on the A-90 Orlyonok ;NK-12MP:{{cvt|11033|kW|hp|order=flip}},<ref name="MP-MK">{{cite encyclopedia |title=NK-12MP, NK-12MK |publisher=Ulyanovsk Higher Aviation School of Civil Aviation |url=http://www.uvauga-dvig.narod.ru/nk-12mp_12mk.pdf |access-date=August 21, 2019 |series=Domestic Aerospace Engineering |page=19 |language=Russian}}</ref> modernized version used on the Tupolev Tu-95MS and Tupolev Tu-142M ;NK-12MPM: Upgraded version of the NK-12MP that develops more power, produces half the vibration and is paired with the Aerosila AV-60T propeller; replaces the NK-12MP engine and AV-60K propeller on the Tupolev Tu-95MS<ref name="AIN20181031">{{cite news |work=AINonline |title=More power for the mighty 'Bear' |url=https://www.ainonline.com/aviation-news/defense/2018-10-31/more-power-mighty-bear |date=31 October 2018 |given=Vladimir |surname=Karnozov |department=Defense}}</ref>

==Applications== [[File:Antonov An-22A on the MAKS-2009 (04).jpg|thumb|A pair of Kuznetsov NK-12MAs installed on an Antonov An-22]] * A-90 Orlyonok * Antonov An-22 * Tupolev Tu-95 * Tupolev Tu-114 * Tupolev Tu-116 * Tupolev Tu-126 * Tupolev Tu-142

==Specifications (NK-12MV)== {{jetspecs <!-- If you do not understand how to use this template, please ask at Wikipedia talk:WikiProject Aircraft --> <!-- Please include units where appropriate (main comes first, alt in parentheses). If data are missing, leave the parameter blank (do not delete it). For additional lines, end your alt units with )</li> and start a new, fully-formatted line with <li> --> | ref = Aircraft engines of the World 1970,<ref name=Wilkinson70>{{cite book |last=Wilkinson |first=Paul H. |title=Aircraft engines of the World 1970 |year=1970 |publisher=Paul H. Wilkinson|location=London |edition=22nd |page=221}}</ref> Civil Turboshaft/Turboprop Specifications<ref>{{Cite web |url=http://www.jet-engine.net/civtsspec.html |title=Civil Turboshaft/Turboprop Specifications |access-date=2011-04-22 |archive-date=2017-07-29 |archive-url=https://web.archive.org/web/20170729043725/http://www.jet-engine.net/civtsspec.html |url-status=dead }}</ref> | type = Turboprop engine | length = {{cvt|6|m|ft}} | diameter = {{cvt|1150|mm|in}} | weight = {{cvt|2900|kg|lb}} | compressor = 14-stage axial flow | combustion = 12 combustion chambers | turbine = 5-stage axial turbine | fueltype = Aviation kerosene such as JP-4 / Soviet spec. T-1 or T-2 | oilsystem = Pressure spray at {{cvt|85|psi|bar|order=flip}} | power = {{cvt|15000|shp|kW|order=flip}} (equivalent) / {{cvt|14750|shp|order=flip}} + {{cvt|625|lbf|kN|order=flip}} at 9,250 rpm | thrust = | compression = 13:1 at 9,250 rpm | bypass = | aircon = {{cvt|65|kg/s|lb/s}} at 9,250 rpm | turbinetemp = {{cvt|1250|K|C}} | fuelcon = | specfuelcon = {{cvt|0.360|lb/hph|kg/kWh|order=flip}} | power/weight = {{cvt|3.7|kW/kg|hp/lb}} | thrust/weight = }}

==See also== {{aircontent <!-- other related articles that have not already linked: --> | see also =

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==References== {{reflist}}

==External links== {{Commons category}} * [https://web.archive.org/web/20110813145414/http://ciad.ssau.ru/work-images/nk-12_big.jpg ciad.ssau.ru - Image] * [http://www.airventure.de/tipps_zentralfinnisches_luftfahrtmuseum/Museum_Finnland_Kuznetsov_Triebwerk.jpg airventure.de - Image, finnish museum] * {{cite web |url=http://aerosila.ru/en/products/vozdushnye-vinty-ivintoventilyatory-dlya-samoletov/vintoventilyatory-klass-tyagi-10000-kgs |title=Propfans: Thrust class > 10000 kgf: Technical characteristics |website=Aerosila |archive-date=October 15, 2017 |url-status=live |archive-url=https://web.archive.org/web/20171015225141/http://aerosila.ru/en/products/vozdushnye-vinty-ivintoventilyatory-dlya-samoletov/vintoventilyatory-klass-tyagi-10000-kgs}}

{{Kuznetsov aeroengines}}

Category:Kuznetsov aircraft engines Category:1950s turboprop engines