Kuznetsov NK-33

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Kuznetsov NK-33/43
AJ26

The Kuznetsov NK-33 (internal 11D111 ) is a Soviet liquid rocket engine from the Kuznetsov design office from Samara , which was originally developed for the N1 moon rocket .

development

The engine was developed in the late 1960s from the NK-15 engine, which was used in all flight tests of the N1 , and was supposed to offer higher thrust and greater reliability than this, as well as being able to be reignited up to 15 times in some cases. In the N1 program, 30 NK-33 engines were to be used in the first stage and eight NK-43 in the second stage. The engines were ready for use in 1974, but were never used because the program was canceled. A total of 208 NK-33 and 42 NK-43 engines were built, of which about 150 were mothballed.

The engines are still very advanced, as they had to achieve maximum thrust for the N1. They work with a very high combustion chamber pressure, regenerative cooling and the main flow process, whereby the fuel delivery turbines are driven by a working gas generated in a pre-combustion chamber ( staged combustion cycle ). This process is only rarely used (for example in the main engines of the space shuttle) because the hot, oxygen-rich exhaust gases from the pre-combustion chamber attack metal and thus damage the main combustion chamber and the nozzle. However, this problem was solved by the Soviet engineers, as demonstrated by long-burning tests in the late 1970s. The engines can be regulated in the range from 55 to 104% of the nominal thrust by changing the excess oxygen during combustion. The variant NK-43 (11D112 or AJ26-60) was designed (similar to the NK-15W) as a modified upper stage variant with a significantly longer nozzle (adaptation to the vacuum ) and thus higher thrust and better specific impulse.

commitment

Nikolai Dmitrijewitsch Kuznetsov suggested the engines for the first stage of the Proton and later for the Zenit rocket in the mid-1970s . However, this was never realized.

Towards the end of the 1990s, the engines that had been in storage for decades were offered for sale to US companies and have since been exported to the USA. They were originally intended to be used on the Kistler K-1 . The Kistler company bought 58 of the still existing NK-33 and 18 NK-43 engines for 440 million US dollars and had them modified by the Aerojet company (some swiveling, replacement of rubber parts, new electronics). The modified engines are called AJ26-58 or 59 (NK-33) or AJ26-60 (NK-43). However, due to the company's insolvency in 2010, the engines were no longer used at Kistler.

The engines were then used in the first stage of the commercial American launch vehicle Antares as the AJ26-62. The successful maiden flight of the Antares rocket took place on April 21, 2013. After the development of the N1 missile in the Soviet Union was canceled before the NK-33 engines were in flight in the N1F, this represents the first use of these engines. After a false start due to engine failure on October 28, 2014, the Antares manufacturer on the Russian RD-181 engine type .

In Russia there have been efforts for a long time to use the NK-33 engines in modernized Soyuz rockets (Soyuz-2.1w, Soyuz-2.3, and Soyuz-3). The first flight of a Soyuz 2.1w with an NK-33 engine in the launch stage took place successfully on December 28, 2013.

Technical specifications

Surname NK-33 NK-43
Thrust (sea level) 1505 kN -
Thrust (vacuum) 1638 kN 1750 kN
Dimensions 1235 kg 1473 kg
length 3.7 m 5.0 m
diameter 2.0 m 2.5 m
fuel LOX / kerosene
Mixing ratio 2.6: 1
Combustion chamber pressure 145 bar
specific impulse 297s 346s
Nozzle expansion ratio 27: 1 80: 1

Web links

Commons : NK-33  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ Bernd Leitenberger: The Russian moon rocket N-1
  2. ↑ a b Space and Tech: NK-33's specifications ( Memento of October 14, 2006 in the Internet Archive )
  3. ↑ Step forward. Flight Global, October 22, 1997, accessed July 28, 2014 .
  4. ↑ J. Hzulka et al: Modification and verification testing of a Russian NK-33 rocket engine for reusable and restartable applications. (PDF (2.4 MB)) In: AIAA 98-3361. American Institute of Aeronautics and Astronautics, 1998, accessed July 28, 2014 .
  5. ↑ NewSpace Journal: Farewell, Rocketplane (in English)
  6. ↑ Antares 230 in the Encyclopedia Astronautica (English)
  7. ↑ engine turbopump eyed in Antares launch failure. In: Spaceflight Now. November 5, 2014, accessed July 27, 2019 .
  8. ↑ RussianSpaceWeb.com: The Soyuz-1 (Soyuz-2-1v) rocket ]
  9. ↑ RussianSpaceWeb.com: Soyuz-2-3 launch vehicle - RussianSpaceWeb.com (in English)
  10. ↑ RussianSpaceWeb.com: Soyuz-3 launch vehicle (in English)
  11. ↑ RussianSpaceWeb.com: The Soyuz-1 (Soyuz-2-1v) rocket (development) (in English)