the first prototype
At the end of the '30s, the Yakovlev bureau has realized two single-engined trainers (UT-1 and UT-2) and a three-seat twin-engined trainer plane, the UT-3 with Renault Bengali 220 cv engines.
This plane was the base for an ambitious project: a plane usable as fast bomber, heavy fighter and reconaissance plane able to reach a top speed of 600 km/h. This was an initiative of Yakovlev himself, without a requet of the VVS (Air force) nor of NKAP (air production ministry), and without funding by State.
To reach a such ambitious goal, Yakovlev had to use the M-103 engines with 960 hp power (neatly inferior to German DB-601); besides he had to use costructive thechniques that he had already mastered.
The Yakovlev bureau tried to draw the plane as small and light as possible, to obtain a mass/power ratio of 2.05 hp/kg; just to make a comparison, the I-16 fighter had 2.09 kg/hp and SB- 2M103 had 3.22 kg/hp. This limited the mass to 3900 kg.
The new plane was smaller than its predecessor UT-3, and had about the size of the De Havilland Comet, the winner of the London-Melbourne race in 1936 (not a warplane!).
The structure of 22 was composite:
an one-piece wooden wing with two spars and was covered by veneer; it was integral with the centre fuselage section. The forward fuselage was made of duraluminium, and the detachable rear fuselage had a steel tube frame covered by fabric (sides and undersurface) and veneer (the back).
To save weight, the wing were not dismountable, and the central position in fuselage, between two longarons, was destined to lodge vertically some 100 kg bombs; this baricentrical position was the best to carry payload. So, the pilot and gunner were lodged in not-communicating positions. The gunner position was highly areodynamical, but he had to open the sliding hood and to lower the rear fuselage back and lift the weapon to fire. All this was unpratical.
The wing was too thin to find place for coolers as on SB, so they had to be located in the reap art of engine nacelles.
The tanks allowed a range of 800 km; the plane was able to carry up to 350 kg of bombs, and two ShKAS 7.62 mm machine guns (one in the nose, the other one in the gunner position); on the fighter version, the ShKAS on the nose had to be replaced by a 20 mm gun. The wingload was very high, 148 kg/m2.
In a following projecting stage, the fighter version was magined as a single-seater armed with two 20 mm guns and 3 ShKAS; the reconaissance version was thought as a two-seater with two ShKAS, 2 bombs off 20 kg, an AFA-19 camera behind the fuel tank, over a ventral window. The bomber version was thought with 4 100 kg bombs in the internal bay and two further 100 kg bombs under the wings.
The fuel tanks had to allow a range up to 1600 km for the reconaissance version.
All these modifies made the weight to increase to 3700 kg, and the wingload to 170 kg/m2 despite the increasing of wingspan to 14 m and of wing area to 29,4 m2.
In January 1939, a meeting in the Kremlin led to leave the project of a multi-purpose plane, and to give priority to the development of single-engined fighters and of fast bombers. So, Yakovlev specialized its project into a fast bomber. This modification required six months. Then, the prototype, simply named "22", was ready for its first flight. It reached a speed of 560 km/h since its first flights; it was higher than those of the most of single-engined fighters in 1939.
However, the plane revealed many weak points:
Yakovlev invited Yakov. Smushkevich, Chief of the VVS and Hero of the Spanish Civil War, to see the plane. He was impressioned by the high speed of the plane, and made a favourable report to Stalin.
Yakovlev was convocated to the Kremlin, where he explained the aerodynamic and structural progresses from its predecessor SB-2M103, that allowed to reach a speed 100 km/h higher with the same engines. Stalin was impressed, and repeated "... a miracle, an aereonautical revolution..." . Unfortunately, all these expectation were destined to be deluded: the 22 was still a sort of racer, not a combat ready plane.
Yakovlev was proposed for the Order of Lenin, and it was decided to produce the plane as BB-22 (BB was for Blizny Bombarderovchtchik, short range bomber) at Zavod 1 in Moscow.
A reconaissance version, named R-12, flew on November 15, 1939, flown by test pilot Piontkovsky; it was equipped by two M-105 engines able of 1050 hp, but it met the same problems of 22 and made only few flights, being abandoned during the summer 1940.
A fighter version named I-29 flew on December 1940; it was powered by two M-105 and armed with two ShVAK 20 mm guns, but the work on it was slow due to the heavy military situation of late 1941, and it was abandoned at the beginning of 1942.
An impressive demonstrative flight of 22 was made on May 1, 1939; some days later, it was decided to send the plane to the state tests. Yakovlev gave two weeks of time to his men to solve all the problems met in the first flights, but this would have required at least a month of work, according to Eugene Adler, head engineer of his bureau. So they had to work day and night at the light of some trucks because the hangar had not electric illumination.
The day of the flight, while the plane is moving towards the runway, its wheel falls into a hole hidden in the grass and reported some damage. Yakovlev ordered to repair the plane in 24 hours, but the repairs required three days.
The 22 was presented as a reconaissance plane able to reach 600 km/h. On May 29, 1939, the test pilot N. Chevarev, the navigator A. Tretyakov and the engineer V. Kholopov of NII VVS (the Scientific Institute of Air Force) were charged of the State tests of this plane.
During the first five flight, a speed of 558 km/h at 4900 m was reached; its time of climb at 5000 m was of 5'45", with a ceiling of 10800 m.
Despite these interesting performances, the NII VVS report concluded that the plane was without use for combat.
General A. Filin, chief of NII VVS, asked to modify the plane and to present it again at state tests on August 1.
The requests were:
On June 20, 1939, ordered the building of 50 planes at Zavod 1in Moscow within 1939, and of further 300 ones at Zavod 81, in Moscow too.
On August 1939, Yakovlev and the equipe testing the 22 were convovcated at Kremlin by Stalin. After the exposition of problems, Stalin asked if the plane was useful for combat, or not. Eng. Kholopov had to expose in detail all the problems. When the men of VVS leaved the rom, Yakovlev convinced Stalin to prosecute the development of BB-22, and informed him of the progress of I-26 (later Yak-1).
The second prototype, BB-22, was started in late summer 1939, and was ready on 31 December; its first flight was made o February 1940.
It was characterized by:
Production BB-22, with lowered rear fuselage and modified canopy rear for D-I-6 turret, obtained a speed of 515 km/h only.
On January 9 1940, Yakovlev was appointed as People's Vice-Commissar of NKAP, that is to say Vice-minister for Aircraft Production, responsable for research. Two days later, the Council of Defence authorized the building of 580 BB-22 in 1940 in Zavod 1 and 81. However, on January 21, the commission of inspection for this plane, constituted by representants of Industry and VVS, admitted that it was not reasonable to build more than 10 planes with such a faible armament.
On 4 March 1940, the Council of Defence decided that a version of BB-22 with M-105 engines had to be built and ready for tests within December 1940. It imposed a speed of 590 km/h and a bomb load of 400 kg.
On the first days of February 1940, the first batch of 10 BB-22 built by Zavod 1 were operationally evaluated. The military representants in factory insisted that many defects had to be remedied before testing, but their opinion was not accomplished.
On 15 February, the tests were stopped due to tail vibrations, failures of the landing gear hydraulic system, failure of turret pneumatic lift mechanism, rupture of engine bolts, weakness of landing gear legs. The landing speed was too high, the stability was poor both laterally and longitudinally, and that the maintenance was difficult (for example, 30 minutes were required to remove the engine cowling, and the cooling system had 20 emptying taps).
Despite the negative response of the pilots and technicians, the plane was put in production, and on April 16 it was decided to present 21 BB-22 at the Parade of May 1, 1940.
At the same parade, it was presented the prototype named 100, a twin-engined high-altitude fighter. It was the first prototype of what became the Petlyakov Pe-2.
On 25 May 1940, it was decided to limit the production of BB-22 at Zavod 1 at 100 planes; the resources of that modern factory had been to be employed for the MiG-1.
A design bureau KB-70 was established to develop the plane and introduce it into production. It was directed by L.Kurbala.
Later, the design bureau KB-70 was sent to Zavod 81 to try to improve the BB-22 produced there, but they revealed the same defects of those produced by Zavod 1. In August, a transfer flight of 22 new BB-22 to 136 BBAP in Kharkov revealed that all the planes had defects.
The following production planes were modified to remedy: the water cooler tunnel was enlarged, and an oil cooler and its intake was added on each nacelle. These modifications increased the weight to 5660 kg, and the wing load to 192 kg/m2, and the speed decreased to 478 km/h at 4600 m, and only 445 km/h with 500 kg of bombs. It was not much more than the older SB.
In October 1940, further modifies reduced the weight, suppressed the vibrations and the defects of anding gear; the speed raised to 500 km/h and the climb and ceiling were improved. The plane remained difficultto fly bacause of its unstability and high landing speed, but these defects couldn't be solved without a radical reprojecting of the plane.
In March 1940, two engines M-105 were installed on the BB-22 n.1002, that was renamed BB-22 bis. It differed from standard BB-22 for the longer exhaust stacks and a metallic plate on the back of the wings to protect them from the hot fumes.
The first tests were conducted in May by the test plot P. Moiseyenko and the navigator F.Pinenov obtaining a speed of 574 km/h at 4800 m, and a climb to 5000 m in 5'45". But the plane went in collision on the ground with a pair of parked SBs, due to brakes misfunctioning.
Although the damage was limited to thewings, the plane was written off because the wing was projected without the possibility to dismount and replace the outer panels.
The second prototype of BB-22bis, n.1045, was started in June. Its oil radiators on the nacelle sides were replaced by a crescent-shaped one under each engine. A new TSS-1 turret (with one ShKAS and 800 rounds) replaced the D-I-6, and the canopy rear was modified. 4 bombs of 125 kg found place under the wingroots. 960 kg of fuel were contained in six tanks, so the range was 1100 km/h at 90% of the max power. Such plane reached 533 km/h, but the wingload raised to 200 kg/m2.
On June 27, the Yakovlev OKB was charged to modify the BB-22 into a dive bomber named Izdelie 31 or BPB-22. It had to be equipped with air brakes and an automatic dive entry/recovery control system. The first prototype was flown by test pilot M.Lapkin in late October 1940; it weighted 5962 kg, and it reached 533 km/h at 5100 m with external bombs load, and 558 km/h without external bomb load..
Furter flight tests were made at Ramenskoe by Y. Paul; this pilot had an accident when the fuel circuit had a problem and both the engines failed; the plane fell like a stone, but he was able to avoid stall and to make an emergency landing; the prototype was heavily damaged and this delayed the tests.
There was a meeting to study ways to remedy the defects of BB-2 and BPB-22, and Kurbala of KB-70 proposed to leghten the plane to 10,17 m to increase its stability; after solving the problems, 1300 planes would have produced at Zavod 81 in 1941. However, the lack of time of Yakovlev bureau due to its heavy involvement in I-26 (later Yak-1) was an obstacle for the development of his twin since 1939.
The Pe-2 dive bomber made its first flight on December 1940, and it resulted immediately preferable to BB-22bis in all respects.
At the beginning of 1941, BB-22 were renamed as Yak-2 and BB-22 bis were renamed as Yak-4.
On February 11, 1941, the Soviet government deletes all orders for Yak-4. At that time, zavod 1 had delivered 81 between prototypes and production Yak-2s; zavod 81 had already delivered 28 Yak-2s and 57 Yak-4s; further 33 Yak-4s were completed.
The total production was 201 planes, including prototypes and two planes destroyed in accidents before delivery.
The first unit to receive Yak-2s was the 136th Short Range Bombers Regiment (BBAP) in Byelorussia; the planes showed many defects, so the training of crews was slowened. The planes were stopped during the rainy fall and the snowy winter, besides, the cold obliged to empty the cooler circuit after each flight. The activity restarted only in April 1941, but, in absence of hangars, many of the planes had their skinning damaged and had to be repaired and repainted.
On 20 June, 136 BBAP had 49 Yak-2 and 5 Yak-4, but only 36 equipages were combat ready for this type, being the other crews just arrived from schools.
The 316 Reconaissance Regiment (RAP) started to receive yak-4s during the fall 1940, but on 22 June, at the date of German attack, this unit had already 19 Yak-2 and 34 Yak-4, but only 6 crews were combat ready, and 12 furter ones were on training.
The 314 RAP started to receive Yaks on early 1941; at the war outbreak, it had 31 operative Yaks, while other 8 had been lost in training, and only 20 crews were operational on this type.
At the war outbreak, the 19 Air Division was based at Byelaya Tcherkov. Its regiments, as 136 BBAP, suffered few losses during the first days of war, but they were hardly hit in July, both on the ground an in combat, being employed in unescorted attack missions.
The type was not well known to Soviet fighter pilots and one was shot down by an I-153 on June 28; On 16 July, the unit had only 4 operational Yak-2s. On 18 July, the last 4 planes didn't find their objectives, hidden by clouds, but one entered spin and was lost, and two were damaged on landing. The only plane that managed to land safely was the only one operative for several days. After that, the Yak-2s were not utilized any more with bad weather.
The last mission of 136 BBAP was made on August 4, when the last two planes were shot down by flak; the unit was deleted, and survived equipages were incorporated into 507 BBAP. The most of these crew didn't perform more than 4-6 war missions, forthemost of reconaissance, because their short runway prevented takeoff with full bomb load.
On June 22, planes of 316 RAP localized a concentration of Ju-88s of KG54 on the Svinice airport, in Poland; unfortunately, the bomber command could not use this information. But on 26, three airports full of German planes were attacked after being signaled by 316 RAP, causing the destruction of 60 planes on the ground.
At the end of July the 316 RAP had only 10 operative Yaks, and was reverted into an autonomous reconaissance squadron.
The 314 RAP lost 32 Yaks in only 127 missions in a month of war. In the second half of July, the unit was trasferred a Moscow and received 18 new Yak-4.
Returning on the Western Front, the unit was located on the same airport of 410 BAP equipped with Pe-2s, and they had occasion to make a comparison between the two planes; of course, it was very unfavourable to Yak-4.
On August 8, 314 RAP had only 8 Yaks in its inventory; its commander, capt. Astakhov, had totalized only 10 missions on Yak-4. The unit wa moved to Petrovsk, equipped with Pe-2s and became the 320 autonomous reconaissance squadron, leaving the Yaks.
Pilots were unsatisfied with the plane, and the BB was interpreted as "Bespolesny Bombardirovchtchnik" , Bomber good to nothing.
Another unit to use Yaks was 207 BAP (Bomber Air Regiment) of the 3rd Long Range Bombers Air Corp; the commander of the IAP, Colonel G. Titov, used Yak-4s alongside DB-3Fin a raid on a bridge across the Berezina river.
Yaks disappeared from the Western front by the end of June, but reappeared in mid July due to new deliveries; 7 or 8 were used on this front until September 1941.
Other units that utilized Yaks were 10, 44, 48 and 53 Medium Range Bombers Air regiments and with 225 Short Range Bomber Air Regiment.
One Yak-4 remained operational with 118 RAP until 1945.