The Dobrynin VD-4K was a

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

six-bank, 24-cylinder,

turbo-compound A turbo-compound engine is a reciprocating engine that employs a turbine to recover energy from the exhaust gases. Instead of using that energy to drive a turbocharger as found in many high-power aircraft engines, the energy is instead sent to ...

, inline engine developed after the end of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. It was superseded by

turboprop A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. Fuel ...

engines before it could be widely used.

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 The Jumo 222 was a German high-power multiple-bank in-line piston aircraft engine from Junkers, designed under the management of Ferdinand Brandner of the Junkers Motorenwerke. Such was the projected performance of the engine compared to c ...

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 In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement. The current categorisation is that a supercharger is a form of forced induct ...

and a

turbocharger In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pro ...

were fitted to the engine itself, which made the VD-4K a

turbo-compound engine A turbo-compound engine is a reciprocating engine that employs a turbine to recover energy from the exhaust gases. Instead of using that energy to drive a turbocharger as found in many high-power aircraft engines, the energy is instead sent to ...

. 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 UEC-Aviadvigatel JSC (Russian: АО "ОДК-Авиадвигатель", lit. Aeroengine) is a Russian developer and builder of aircraft engines, most notably jet engines for commercial aircraft. Based at the Perm Engine Plant, its products powe ...

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 The Tupolev Tu-85 (russian: Туполев Ту-85; USAF/ DoD reporting name: "Type 31", NATO reporting name: Barge) was a Soviet prototype strategic bomber based on the Tu-4, an unlicensed, reverse engineered copy of the Boeing B-29 Superfort ...

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 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, diameter (NK-12MA), and diameter (NK-12MV). It is the most powerful ...

— itself developed and in test by 1951 — and used on the

Tupolev Tu-95 The Tupolev Tu-95 (russian: Туполев Ту-95; NATO reporting name: "Bear") is a large, four-engine turboprop-powered strategic bomber and missile platform. First flown in 1952, the Tu-95 entered service with the Long-Range Aviation of the ...

strategic bomberGunston, p. 244

Applications

Tupolev Tu-4 The Tupolev Tu-4 (russian: Туполев Ту-4; NATO reporting name: Bull) is a piston-engined Soviet strategic bomber that served the Soviet Air Force from the late 1940s to mid-1960s. It was reverse-engineered from the American Boeing B-29 S ...

Specifications (VD-4K)

References

Notes

Bibliography

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External links

VD-4

{{Webarchive, url=https://web.archive.org/web/20150214205611/http://missiles.ru/Saturn-muzey-2010.htm , date=2015-02-14 1950s aircraft piston engines Inline radial engines Water-cooled radial engines