history and images
|The powerful VK-108 engine (also called VK-107B) of 1800 hp differed
from the VK-107A mainly for his new supercharger.
This 12-cylinders engine gave a power of 1800 hp at altitude.
This engine never entered in series production,
Less than 50 VK-108 were built, plus some VK-108NV injection engines; it development was stopped because of the advent of the jet age.
A VK-108 was intalled on a Yak-3 airframe in 1944 for experiment only.
|The prototype building started on 1 August 1944.
The most recognizable characteristic of the Yak-3 VK-108 prototype was the presence of 24 exhaust stacks, aligned in four lines of six, on the nose sides and upper cowling.
Besides, the supercharger air intake was divided from those of oil coolers at the wingroot, and moved under the nose as on Spitfire.
The armament was reduced to the NS-23 gun only, firing through the propeller's hub.
The leader of the project was eng. A. Kanookov.
The aircraft rolled out on 1st October 1944,
flown by test pilot V. Rastorguyev.
The factory tests started on 7 October 1944.
On 21st December, 1944, the aircraft was flown after having been lightened to 2830 kg by omitting the gun and part of the fuel.
It took off on three points (without raising the tail), climbed to 5000 m in 3.5 mins only, and reached 745 km/h at 6290 m.
These impressing performances were inficiated by strong overheating, vibrations, smoke emission and many engine faults.
After this flight, the aircraft was landed to replace the engine.
The work was discontinued on 8 March, 1945, after the first flight with the new engine, still badly functioning.
Some further trying to improve the aircraft were made since August 1, 1945 under the supervision of ing. G.Grigoryev; the prototype was armed with two syncronized B-20S guns with 120 rounds each, but the work didn't give the hoped results.
In 1946, the NKAP ordered the construction of 3 further prototypes, but the project was soon abandoned due to the advent of jets.
|standard Yak-3||Yak-3 VK-107 prototype||Yak-3 VK-107
|year of production||1943||1944||1945||1946||1944||1944|
|wing area (sqm)||14.85||14.85||14.85||14.85||17.15||14.85|
|empty weight (kg)||2128||2512|
|gross weight (kg)||2697||2984||2935||3204||2830|
|Max speed at sea level (km/h)||565||611||604||600|
|at altitude of||4400||5750||5900||5900||6000|
|Climb to 5000 m (min)||4.1||3.9||4.2-4.5||5.0||3.5|
|turn time (s)||19||18||18||20|
2x12,7 mm UBS
|2x20 mm||2-3 20 mm guns||2-3x 20 mm||1x20 mm+
2x12,7 mm UBS