Kuznetsov NK-12

NK-12
NK-12M Turboprop engine on a Tu-95 at RIAT Fairford 1993
Type	Turboprop
National origin	Soviet Union
Manufacturer	Kuznetsov Design Bureau
Major applications	Antonov An-22 Tupolev Tu-95 Tupolev Tu-114

The exhaust ports of a NK-12 in an outboard nacelle on a TU-95

The Kuznetsov NK-12 is a Soviet turboprop engine of the 1950s, designed by the Kuznetsov design bureau. It drives huge eight-bladed (four per propeller) contra-rotating propellers 5.6 m (18ft 4.5in) in diameter (6.2 m (20ft 4.1in) in the NK-12MA and NK-12MV).

Design and development

The NK 12 turboprop was originally developed after World War II by a German ex-Junkers team under Ferdinand Brandner, evolving from late war German turboprop studies. This started with the post-war development of the wartime Jumo 022 turboprop design that developed 6000 ehp in a 3000 kg engine. The effort continued with a 5000 ehp engine that weighed in at 1700 kg, completed by 1947. The evolution to the TV-12 12000 Ehp engine required extensive use of new Soviet-developed alloys and was completed in 1951.^[1]

The NK-12M developed 8,948 kW (12,000 ehp), uprated in the NK-12MV to 11,033 kW (14,795 ehp) and reaching 11,185 kW (15,000 ehp) in the NK-12MA. The NK-12 is by a wide margin the most powerful turboprop engine ever built. Only recently the Progress D-27 and Europrop TP400 came somewhat close. It powered the Tupolev Tu-95 / Tu-142 bombers. The Tupolev Tu-114 airliner (with NK-12MV) is still the world's fastest propeller-driven aircraft, and the Antonov An-22 Antheus (with NK-12MA) was the world's largest aircraft at the time. It has also been used to power several types of amphibious assault craft, such as the A-90 Orlyonok "Ekranoplan" and the Zubr class LCAC.

The engine has a 14-stage axial-flow compressor, producing compression ratios between 9:1 to 13:1 depending on altitude, also controlled by variable inlet guide vanes and blow-off valves. The combustion system used is a cannular-type: each flame tube is centrally mounted on a down-stream injector that ends in an annular secondary region. The contra-rotating propellers and compressor are driven by the 5-stage axial turbine. Mass flow is 65 kg (143 lb) /sec.^[2]

Applications

• A-90 Orlyonok
• Zubr class LCAC
• Antonov An-22
• Tupolev Tu-95
• Tupolev Tu-142
• Tupolev Tu-114

Specifications

General characteristics

• Type: Turboprop
• Length: 4.8m^[2]
• Diameter: 1.2m^[2]
• Dry weight: 2,900kg (6393 lbs), for NK-12MV

Components

• Compressor: Axial flow, 14 stages^[2]
• Turbine: 5 stages^[2]

Performance

• Maximum power output: 11,033 kW (14,795 ehp), for NK-12MV
• Overall pressure ratio: 9.5^[2]
• Turbine inlet temperature: 1250K^[2]
• Specific fuel consumption: 0.360 lb/shp-hr ^[3] 0.219 kg/kW-hr for NK-12MA and NK-12MV
• Power-to-weight ratio: 3.7 kW/kg (2.3 hp/lb), for NK-12MV

See also

Related lists

• List of aircraft engines
  

References

1. ^ Kuznetsov NK-12 (Russian Federation) - Jane's Aero-Engines
2. ^ ^{a b c d e f g} Creation of the TV-2 (NK-12) turboprop engine
3. ^ Civil Turboshaft/Turboprop Specifications

External links

• ciad.ssau.ru - Image