Yakolev Ya-22 / I-29 / BB-22 / R-12 / Yak-2 / Yak-4 / Ya-4
In 1938, the UV-VS (Upravlenie Voenno-vozdushnikh Sil - Administration of the Air Force) formulated a requirement for a two-seat multi-role high-speed combat aircraft. To meet this demand, the OKB (Experimental Construction Bureau) headed by Aleksandr S Yakolev evolved the Ya-22, or Samolet 22. An aerodynamically clean, two-seat low-wing cantilever monoplane of mixed construction and powered by two 960hp M-103A (V Ya Klimov-developed two-speed supercharged derivative of the Hispano-Suiza 12Y) 12-cylinder Vee-type engines, the Ya-22 was proposed in three dedicated versions: long-range escort fighter, short-range bomber and tactical reconnaissance aircraft. Prototypes of all three variants were built simultaneously, the first to fly being the fighter, which, assigned the NKAP (State Commissariat for Aviation Industry) designation I-29, made its maiden flight on 22 February.
Yakolev was then instructed to modify the design to serve as a bomber, the aircraft being redesignated BB-22 (blizhnii bombardirovshchik or short-range bomber). This resulted in major revisions of accommodation, armament and fuel storage, plus the provision of an internal bomb bay. The BB-22 bomber and R-12 reconnaissance prototypes differed from the I-29 primarily in that the fuel tank immediately aft of the cockpit was supplanted by a bay accommodating either eight 50kg bombs in the BB-22 or photo-flashes (for use in conjunction with a single AFA-13 camera) in the R-12. The I-29 had twin 20mm ShVAK cannon in fairings beneath the forward fuselage and a single 7.62mm ShKAS for the aft-positioned observer/navigator, deployment of this gun being permitted by lowering of the aft-fuselage top decking. On 15 March 1939, shortly after commencement of flight testing, Yosif Stalin personally decided to order production of the bomber variant (as the M-105-powered Yak-2) to the exclusion of both fighter and reconnaissance versions.
The first series BB-22 was completed on 31 December 1939 and flown on skis on 20 February 1940. By that time two factories were in production and experimental variants - the R-12 photographic reconnaissance aircraft and I-29 (or BB-22IS) long-range escort fighter - were being prepared for test flights. The BB-22 was redesignated Yak-2 at the end of 1940, and as powered by two 716kW M-103 Vee engines had a maximum speed of 530km/h at sea level service ceiling of 8800m and range of 800km.
In 1940 the basic design was further refined to improve the crew positions, field of view and armour protection; the M-105 engine was introduced with better protection for the fuel system, and provisions were made for external bomb racks. Then redesignated Yak-4, the aircraft entered production in the autumn of 1940 and about 600 of both versions were built, the majority of them Yak-4s . They were not particularly successful in service, many of them being lost in the early days of the German invasion.
Max take-off weight: 5023 kg / 11074 lb
Empty weight: 3796 kg / 8369 lb
Wingspan: 14.00 m / 46 ft 11 in
Length: 10.18 m / 33 ft 5 in
Height: 3.30 m / 11 ft 10 in
Wing area: 29.40 sq.m / 316.46 sq ft
Max. speed: 567 km/h / 352 mph
Range: 1050 km / 652 miles
Engine: 2 x M-105R, 810kW
Max take-off weight: 5245 kg / 11563 lb
Wingspan: 14.0 m / 46 ft 11 in
Length: 10.2 m / 33 ft 6 in
Wing area: 32.0 sq.m / 344.44 sq ft
Max. speed: 530 km/h / 329 mph
Ceiling: 9500 m / 31150 ft
Range w/max.fuel: 1600 km / 994 miles
Range w/max.payload: 800 km / 497 miles
Armament: 1 x 7.62mm machine-gun
Bombload: 400 kg
Yakolev Yak-4 (BB-22)
Yakolev Ya-22 (I-29)