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The Dobrynin VD-4K was a Soviet six-bank, 24-cylinder, turbo-compound, inline engine developed after the end of World War II. It was superseded by turboprop engines before it could be widely used.

Dobrynin VD-4K
Type	Six-bank turbo-compound, inline engine
National origin	Soviet Union
Manufacturer	Dobrynin OKB-36 in Rybinsk
First run	June 1950
Major applications	Tupolev Tu-85
Number built	23

Development

The VD-4K, originally designated as the M-253K, was a development of the post-war VD-3TK (M-251K) engine. Like Nazi Germany's experimental Junkers Jumo 222 multibank wartime engine, the VD-4K had six monobloc banks, each with four liquid-cooled cylinders. However, the VD-4K had a larger displacement figure — at nearly 59.5 litres — than any planned or tested development of the German powerplant; itself only planned to have a top displacement figure of 55.5 litres, with a 145 x 140 mm bore-stroke figure for each cylinder in its planned 222C/D version. The VD-4K utilized a trio of blow-down exhaust, also known as power-recovery, turbines were fitted between the cylinder banks, and a geared centrifugal supercharger and a turbocharger were fitted to the engine itself, which made the VD-4K a turbo-compound engine.

Development began in January 1949 and construction of the prototype began in September of that year. The first engine was completed in January 1950 and it underwent its 100-hour tests in June. It successfully passed its State acceptance tests in January–February 1951. It was evaluated aboard a Tupolev Tu-4 bomber in 1950, itself powered with a quartet of the Shvetsov OKB's 1946-origin, ASh-73 radial engines, each of a displacement figure of 58.1 litres, somewhat close to that of the Dobrynin multibank powerplant design. The Dobrynin engines were most notably fitted to the two prototypes of the Tupolev Tu-85 bomber, but the aircraft, and its engines, was not placed into production because of the promise offered by turboprop engines of immensely more power, like the Kuznetsov NK-12 — itself developed and in test by 1951[1] — and used on the Tupolev Tu-95 strategic bomber[2]

Applications

• Tupolev Tu-4
• Tupolev Tu-85

Specifications (VD-4K)

Data from Kotelnikov[3]

General characteristics

• Type: 6-bank, 24-cylinder, turbo-compound inline engine
• Bore: 148 mm (5.8 in)
• Stroke: 144 mm (5.7 in)
• Displacement: 59.43 L (3,627 cu in)
• Length: 2.5 m (8 ft 2 in)
• Diameter: 1.4 m (4 ft 7 in)
• Dry weight: 4,553 lb (2,065 kg)

Components

• Cooling system: Liquid-cooled

Performance

• Power output: 4,300 hp (3,200 kW)
• Compression ratio: 7:1

See also

Comparable engines

• Napier Nomad
• Armstrong Siddeley Hyena
• Armstrong Siddeley Deerhound
• Lycoming R-7755
• Daimler-Benz DB 604
• Shvetsov ASh-2
• Wright R-2160 Tornado
• Junkers Jumo 222
• BMW 803

Related lists

• List of aircraft engines

References

Notes

Bibliography

• Gunston, Bill (1995). Tupolev Aircraft since 1922. Annapolis, Maryland: Naval Institute Press. ISBN 1-55750-882-8.
• Kotelnikov, Vladimir (2005). Russian Piston Aero Engines. Marlborough, Wiltshire: Crowood Press. ISBN 1-86126-702-9.

External links

• VD-4 Archived 2015-09-24 at the Wayback Machine
• Dobrynin Museum, including picture of a restored VD-4 Archived 2015-02-14 at the Wayback Machine

На других языках

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[de] Dobrynin WD-4K

Der Dobrynin WD-4K (russisch Добрынин ВД-4К) war die letzte Version eines sowjetischen Flugmotors vom OKB-36 in Rybinsk. Er wurde Ende der 1940er- bis Anfang der 1950er-Jahre von Wladimir Dobrynin entwickelt und gebaut und markierte den Höhepunkt der sowjetischen Entwicklung von Flugzeug-Kolbenmotoren.

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- [en] Dobrynin VD-4K

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[it] Dobrynin VD-4K

Il Dobrynin VD-4K, in alfabeto cirillico ВД-4К, era un motore aeronautico radiale a 24 cilindri a sestupla stella raffreddato a liquido, progettato dall'OKB 36 diretto da Vladimir Alekseevič Dobrynin e sviluppato in Unione Sovietica tra la fine degli anni quaranta e l'inizio degli anni cinquanta.

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[ru] ВД-4К

М-253К (ВД-4К) — мощный советский авиадвигатель комбинированного типа (турбокомпаундный), выполненный по схеме звезды блоков.

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