VK-107

VK-107
Name	VK-107
Type	Aircraft piston engine
Manufacturer	Klimov (OKB-117)
First flight	1944
Introduced	1944
Retired	1946
Primary user	Soviet Air Forces
Produced	1944–1947
Number built	~2,000

VK-107

The VK-107 was a high-performance liquid-cooled aircraft piston engine developed in the Soviet Union during World War II by the Klimov design bureau (OKB-117) under chief designers who had previously worked on the Mikulin AM-35 and Klimov M-105. Intended to power late-war fighters and experimental designs, the engine sought to match contemporary powerplants such as the Rolls-Royce Griffon, Daimler-Benz DB 605, and Allison V-1710 in output and altitude capability. Development intersected with programs led by the Soviet Air Forces and industrial priorities set by the Soviet Union's wartime leadership, including directives from the People's Commissariat of Aviation Industry.

Design and Development

The VK-107 project was initiated amid competing efforts at OKB-117 and other bureaux like Shvetsov and Mikulin to deliver increased horsepower for fighters such as the Lavochkin La-7, Yakovlev Yak-3, and proposed MiG designs. Drawing on lessons from the AM-38 and M-105 families, Klimov engineers redesigned cylinder heads, valve trains, and crankshafts, incorporating centerline supercharging influenced by research sharing with TsAGI and technical exchanges following contacts with Lend-Lease technicians. The program emphasized materials allocation overseen by ministries including the People's Commissariat of Heavy Industry and production planning coordinated with plants like Factory No. 26 and Factory No. 45 in Moscow and Kazan.

Prototypes underwent bench testing at state test centers affiliated with NII VVS and flight trials on airframes including modified La-5 and Yak-9 prototypes. Flight-clearance procedures involved acceptance trials conducted near Khimki and telemetry analysis compared against engines such as the BMW 801 and the Shvetsov ASh-82.

Technical Specifications

The VK-107 was a 12-cylinder, inverted V-type liquid-cooled engine featuring a two-stage supercharger, sodium-cooled valves, and magnesium alloy components developed under metallurgical programs tied to institutes like Academy of Sciences of the USSR laboratories. It produced ratings in the 1,300–1,650 horsepower range depending on mark and boost settings, comparable to the DB 605 series in certain envelopes. Bore, stroke, displacement, compression ratio, and weight figures were refined through iterations and tooling adjustments at plants coordinated with the State Committee on Defense.

Fuel and lubrication systems were designed to use grades standardized by supply agencies linked to Gosplan allocations, while accessory drives and reduction gearing permitted integration with propellers supplied by manufacturers such as the Sukhoi supply chain and propeller divisions supporting fighters like the La-7 and prototypes destined for Polikarpov-linked projects.

Operational Service

VK-107-powered aircraft entered operational units late in World War II with deployments to frontline regiments within the Soviet Air Forces in 1944–1945. Units operating engines engaged in sorties over sectors including the Belorussian Offensive and Vistula–Oder Offensive, supporting ground formations from armies such as the Red Army combined-arms groups. Maintenance and logistics were handled through rear-echelon depots and repair workshops tied to the Rear Services of the air force; corrosion and overheating issues prompted concentrated service bulletins issued by the Air Force Scientific Test Institute.

Postwar, the engine saw limited service with training and interceptor conversion programs as the Soviet Union transitioned to jet propulsion exemplified by programs at OKB Mikoyan-Gurevich and Sukhoi, and VK-107 units were gradually withdrawn as jets like the MiG-15 entered service.

Variants and Modifications

Production variants included boosted and de-rated marks intended for differing airframe fits: a high-altitude two-stage supercharged mark, a low-altitude single-stage de-rated mark for mass-production fighters, and naval adaptations for carrier or coastal aviation projects coordinated with People's Commissariat of the Navy requirements. Modified versions experimented with water injection systems influenced by trials at Central Aerohydrodynamic Institute facilities and different reduction gears to accommodate contra-rotating propeller trials led by design groups associated with TsAGI.

Experimental modifications addressed metallurgy shortages by substituting alloys approved by procurement offices tied to the Ministry of Aviation Industry, while field kits were developed to improve reliability under austere conditions encountered by regiments operating in theaters like East Prussia and Karelia.

Production and Manufacturing

Manufacture was undertaken at dispersed facilities including plants historically designated as Factory No. 26 and Factory No. 45, with ancillary components produced in Kuibyshev and Gorky. Production ramp-up demanded coordination with logistics networks managed by the People's Commissariat for Transport and workforce training overseen by vocational institutes and technical schools funded by Ministry of Higher Education directives. Wartime strain on supplies led to quality-control challenges documented in internal reports circulated among ministries and inspected by ordnance committees.

Tooling, jigs, and ground-test rigs were standardized across manufacturing lines following guidelines from engineering directorates aligned with Narkomsvyaz-issued industrial standards, while postwar rationalization consolidated manufacturing into fewer installations as focus shifted toward jet engines developed by OKB-1 and other emerging bureaus.

Performance and Evaluation

Field and bench evaluations recorded that the VK-107 delivered improved peak power over predecessors, enabling better climb and speed in fitted fighters, but suffered from reduced service life and higher maintenance demands than anticipated. Comparative assessments by test centers placed its reliability below that of established powerplants like the Shvetsov ASh-82 under frontier conditions, though it matched contemporary Rolls-Royce and Daimler-Benz outputs in controlled trials. The engine's legacy influenced subsequent Soviet piston engine work and informed transition planning within aviation programs led by designers from Lavochkin, Yakovlev, and MiG bureaux.

Category:Soviet aircraft engines