Monday, March 16, 2015

Yakovlev Yak 3 Fighter

Design began at the end of 1941 of an all new single seat fighter using the new VK-107 engine, requiring the least possible drag, smallest dimensions and weight consistent with a manoeuvrable and tough machine. Due to delays with the VK-107 engine and pressure to build the maximum number of aircraft already on the production lines, this new Yak-3 programme was shelved.

A new smaller wing was developed, the oil cooler was replaced with small twin coolers in the wing root, the rear fuselage deck was cut down and an clear view canopy was used along with other changes was tested on a single Yak-1M in late 1942. This experimental aircraft proved very successful, and a single prototype under the designation Yak-3 was ordered. This Yak-3 prototype first flew in late 1943. Although evaluation aircraft flew in combat, the first series Yak-3s did not enter operational service until July 1944, with the 91st IAP. It’s of interest that all production Yak-3s were given a thick coat of wax polish to improve streamlining.

The Yak-3 was found to be an exceptional dogfighter at altitudes up to 13,125 ft (4000 m). Its improved performance was remarkable, particularly as the initial non-availability of the VK-107 engine forced reliance to be placed on the VK-105PF-2 that had powered earlier Yaks. Built to a total of 4,848, the Yak-3 achieved fame and a very high score against German aircraft in 1944-45. The Yak-3 equipped the famous Free French 'Normandie-Niemen' unit which actually turned down the use of American P-39s and Soviet Yak-9s in favour of the Yak-3. The Yak-3 achieved its peak of perfection when the 1,700 hp (1268 kw) VK-107A engine became available (although in limited numbers) in August 1944, which improved its performance to 447 mph (720 km/h) at 19,685 ft (6000 m).

On 14 July 1944 a group of 18 Yak-3s ran into a flight of 30 Luftwaffe fighters. During the course of the battle, 15 Luftwaffe aircraft were shot down with the loss of only one Yak-3. This fighter eventually became so dangerous to the Luftwaffe that in late 1944 they issued a directive to all Luftwaffe pilots to avoid combat under 5000 m with any Yakovlev fighter that lacked an oil cooler under the nose.

About 100 Yak-3s with the 1,700 hp (1268 kw) Klimov KV-107A engine. They began operational service in early 1945.
An experimental aircraft with the Klimov VK-108 engine. This aircraft first flew on 19 December 1944 and demonstrated a maximum speed of 463 mph (745 km/h) at 19,685 ft (6000 m). It was this version that proved to be the fastest of all Yak-3 variants.
An anti-tank version built in small numbers with a 37 mm N-37 cannon and two 20 mm B-20S cannon.
A one off Yak-3 with a 57 mm OKB-16-57 cannon.
A small quantity of aircraft built with three 20 mm B-20 cannon and two 12.7 mm (0.50 in) UBS machine guns.
Yak-3RD (or Yak-3D)
An adaptation of series aircraft which incorporated the Glushko RD-1 rocket unit in the tail of the aircraft.
A high altitude version.
Rebuilt aircraft with the ASh-82FN radial engine and twin B-20 cannon. Despite the fact the engine was heavier than the previous engines, this version actually weighted less than the standard Yak-3. During a series of test flights started on 12 May 1945, the aircraft achieve a maximum speed of 441 mph (710 km/h) at 20,015 ft (6100 m).
A Yk-3 with the Klimov VK-107A and a turbocharger tested in 1945.
Developed as a conversion trainer in late 1945 with the ASh-21 radial engine. Eventually became the Yak-11 trainer.

Specifications (Yakovlev Yak-3)
Type: Single Seat Fighter / Interceptor
Design: Aleksandr Sergeyevich Yakolev
Manufacturer: State Industries
Powerplant: One 1,300 hp (969 kw) Klimov VK-105PF-2 12-cylinder Vee engine.
Performance: Maximum speed 407 mph (655 km/h) at 10,170 ft (3100 m); service ceiling 35,105 ft (10700 m).
Range: 559 miles (900 km) on internal fuel.
Weight: Empty equipped 4,641 lbs (2105 kg) with a maximum take-off weight of 5,864 lbs (2660 kg).
Dimensions: Span 30 ft 1/4 in (9.20 m); length 27 ft 10 1/4 in (8.49 m); height 7 ft 11 1/4 in (2.42 m); wing area 159.53 sq ft (14.83 sq m).
Armament: One engine mounted 20 mm ShVAK cannon with 120 rounds and two synchronised 12.7 mm (0.50 in) UBS machine guns with 250 rounds each.
Variants: Yak-3 (initial production), Yak-3/VK-107A (about 100 aircraft built), Yak-3/VK-108 (experimental with the VK-108 engine), Yak-3T (anti-tank version with one 37 mm and two 20 mm cannon), Yak-3T-57 (anti-tank version mounting a 57 mm cannon), Yak-3P, Yak-3RD or Yak-3D (experimental), Yak-3V (high altitude), Yak-3PD (VK-106 engine), Yak-3U (radial engine), Yak-3TK (VK-107A engine with turbocharger), Yak-3UTI (conversion trainer).
Operators: Soviet Union, Czechoslovakia, Poland, Free French Forces.

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