Yakovlev Yak-2

Bimoteur léger soviétique pas très connu.

Sur Wikipedia in english :

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The [Vous devez être inscrit et connecté pour voir ce lien] Yak-2 was a short-range [Vous devez être inscrit et connecté pour voir ce lien]/[Vous devez être inscrit et connecté pour voir ce lien] aircraft used during [Vous devez être inscrit et connecté pour voir ce lien]. It was produced in small numbers and they were mostly destroyed during the opening stages of [Vous devez être inscrit et connecté pour voir ce lien].

Design and Development


The Yak-2 was initially known as the Ya-22, in the Yakovlev [Vous devez être inscrit et connecté pour voir ce lien] numbering sequence, before it was redesignated
as the Yak-2 in 1941.

It was of mixed construction with wooden wings and center fuselage, [Vous devez être inscrit et connecté pour voir ce lien] forward fuselage, and steel tube framing in the rear fuselage with a wooden upper decking and fabric skin.

The cockpit was at the very tip of the nose, but the navigator/gunner was in a compartment behind the trailing edge of the wing.

The prototype was unarmed and no bomb shackles were fitted. It also lacked a radio and navigational equipment.

It was, however, the fastest aircraft in the Soviet Union, able to reach 567 km/h (352 mph) at 9,900 m (32,000 ft), not least because it lacked all that heavy military equipment.

Le prototype visible sur Wikip

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[Vous devez être inscrit et connecté pour voir ce lien] rather precipitously ordered it into production, as the BB-22
(Ближний бомбардировщик, Blizhniy Bombardirovshchik— short-range bomber), on 15 March 1939 before it could be evaluated by the NII VVS (Naoochno-Issledovatel'skiy Institoot Voyenno-Vozdooshnykh Seel – Air Force Scientific Test Institute).

Their tests were conducted in the early summer and concluded that the engine cooling systems were inadequate, the
brakes were troublesome and the fuel system was unreliable.

The task of converting the aircraft to a bomber was formidable and included redesigning the center fuselage to
accommodate the gunner/navigator immediately aft of the pilot and provision of two 7.62 mm (0.300 in) [Vous devez être inscrit et connecté pour voir ce lien], one for the gunner and the other fixed in the nose.

The rear decking of the fuselage was hinged to pivot down to allow the rear gunner to use his gun.

Factory No. 1 produced the first pre-production BB-22 in December 1939, although it did not make its first flight until the following February.

It was submitted for its service evaluation in March-April 1940 and proved to be a disappointment.

Gross weight had increased 357 kg (790 lb) despite the reduction in fuel from 1,000 kg (2,200 lb) 600 kg (1,300 lb)
and the maximum speed had declined to 515 km/h (320 mph) at 5,000 m (16,000 ft).

The engine cooling system was still unsatisfactory and the [Vous devez être inscrit et connecté pour voir ce lien] was too weak. Longitudinal and lateral stability was also unsatisfactory which made it suitable only for well-trained pilots.

The test programme report concluded that it was not combat-capable and reliable and that flights with a 400 kg
(880 lb) bomb load could be dangerous to the crew.

A remediation program was begun which replaced the single-wheel main landing gear with two-wheeled units and the fuselage upper decking was cut down.

Around the same time Factory No. 1 ceased production and Factory No. 81 in [Vous devez être inscrit et connecté pour voir ce lien] continued to work on the aircraft.

Aircraft built by Factory No. 81 were of better quality because the surface finish was better and the engine cowlings and doors were more closely fitted to minimize drag.

These improvements increased the speed by 10–20 km/h (6.2–12 mph). Development work continued and resulted in the [Vous devez être inscrit et connecté pour voir ce lien] when [Vous devez être inscrit et connecté pour voir ce lien] engines were fitted.

A grand total of 201 Yak-2s and Yak-4s were built before production was terminated in April 1941.

Bill Gunston reports that several prototype variants were built, including the R-12 reconnaissance aircraft which retained the original positioning of the crew, put three cameras in the fuselage and added a bomb bay for eight 20 kg (44 lb) FAB-20 bombs behind the pilot.

Another was the I-29 or BB-22IS escort fighter with restored fuel and two 20 ShVAK cannon underneath the fuselage.

But neither of these can be confirmed by other, post-Cold-War sources.

Yefim Gordon does mention a Yak-2KABB ground-attack variant which might have been confused with the I-29
because it had two ShKAS in the nose and two 20 mm (0.79 in) [Vous devez être inscrit et connecté pour voir ce lien] in a depressible ventral pack.

Unfortunately no other details are available, although photos do exist.

Another variant mentioned by Gordon was the BPB-22 (Blizhiy Pikeeruyushchiy Bombardirovshchik — short-range [Vous devez être inscrit et connecté pour voir ce lien]) prototype that was fitted with two Klimov M-105 engines, dive brakes and an automatic dive entry/exit control
system.

It was first flown at the end of October 1940 although it crashed during the test programme when fuel unexpectedly cut-out, but not before it was flown to a maximum speed of 558 km/h (347 mph).




Operational history


When the Germans [Vous devez être inscrit et connecté pour voir ce lien] the Soviet Union on 22 Jun 1941 73 Yak-2s were in service, mostly with the 316th Reconnaissance Regiment in the [Vous devez être inscrit et connecté pour voir ce lien].

Most of these were destroyed in the opening days of the campaign; the 316th only mustered four on 11 July.

Une vue du Klimov M 105, le 103 V12 étant antérieur mais utilisant les même bloc

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Performance

• [Vous devez être inscrit et connecté pour voir ce lien]: 515 km/h (321 mph)
  
• [Vous devez être inscrit et connecté pour voir ce lien]: 800 km (499 miles)
  
• [Vous devez être inscrit et connecté pour voir ce lien]: 8,900 m (29,192 ft)
  
• [Vous devez être inscrit et connecté pour voir ce lien]: 650 m/min (2,132 ft/min)
  
• [Vous devez être inscrit et connecté pour voir ce lien]: 183 kg/m² (38 lb/ft²)
  
• [Vous devez être inscrit et connecté pour voir ce lien]: 0.27 kW/kg (0.16 hp/lb)
  

Armament

• 2 × 7.62 mm ShKAS machine guns
  
• up to 600 kg (1,300 lb) of bombs
  

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Як-2 КАББ


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