During the Great Patriotic War, the design bureau headed by A.S.Yakovlev presented a series of single-engine fighters and twin-engine light bmbers and transport aircraft. Conveniently, the single-engine aircraft had odd numbers [eg, Yak-1, Yak-3, etc], while the twin- engine aircraft had even numbers [eg, Yak-2, Yak-4, etc]. Not surprisingly, this simplicity did not last long.
The twin-engine low-wing Yakovlev Yak-6, conceived as a light general-purpose transport aircraft, first flew in June 1942. It was equipped with a retractable landing gear with a tail wheel and carried a crew of two, as well as four passengers. The NBB variant (night near bomber) had under-vent suspensions for five bombs and provided for the installation of a ShKAS machine gun of 7.7 mm (0.303 inches) caliber. The Yak-6 could also be equipped for the carriage of goods or for use as an ambulance plane, a glider tower or an attack aircraft carrying 10 RS-82 missiles. The Yak-6 often flew with the main landing gear closed in the released position, it was used to supply the partisans. The total number of aircraft built was about 1000 cars. The Yak-6M was an improved version as a result of the further development of which in early 1944. flew into the air Yak-8. It was large, claimed the role of a specialized transport aircraft, but not commercially produced.
For quite a long time, the role of courier and light transport aircraft was performed by the R-5 and U-2 biplanes designed by Polykarpov. Needless to say, the aircraft were reliable and well-proven in operation, however, in terms of their payload, they did not quite suit either the Air Force or the Civil Air Fleet. The maximum number of passengers taken on board was limited to three people, while the weight of the additional load was significantly reduced. In addition, the Air Force wanted a reliable communications aircraft, like the Fh-204 or, at worst, the Caudron C.440. These aircraft had quite good loading capacity and capacity with rather weak motors. There were no serial analogs in the USSR, except for several PS-35, which were mobilized only in June 1941.
Actually, nobody seriously dealt with this topic in the Land of the Soviets, so Deputy Aviation Commissar A.S.Yakovlev decided to take it himself. To reproach him for unprofessionalism would simply be incorrect, but the goals that he set for the Yakovlev team were not at all easy. The first “test of the pen” took place in 1938, when the S-17 two-engine multipurpose aircraft (later renamed the UT-3) and its passenger modification I-19 arrived at the tests. NCAP initially showed genuine interest in S-17, but so far the tests (too successful), the priorities changed, and the serial production of this aircraft did not go forward. Nevertheless, Yakovlev managed to get an order for a small series of UT-3s, some of which were limited in use in 1941-1942.
With the beginning of the war, there was no time to engage in such airplanes and they returned to this topic only the next year. In the spring of 1942, at a meeting with Stalin, Yakovlev came up with the initiative to build a small transport aircraft, which could easily be produced in large quantities and at the same time not to use scarce aviation aluminum. In other words, Yakovlev suggested that, in the shortest possible time, without actually conducting the full test cycle, launching the production of airplanes as simple as a “plywood box.” Stalin liked this idea because the army had a great need for such an aircraft carrying several passengers.
Naturally the plane is not created from scratch. When designing the future Yak-6, designers actively used developments in the I-19, from which they borrowed the shape of the fuselage, the wings and some other structural elements. The design of the aircraft was 90% made of wood. The frame of the Yak-6 was made of pine and birch plywood and sheathed in canvas. Screws were also made of birch, although usually more solid wood or metal was used for this purpose. In order to save even the gas tanks made their plywood, seriously harming the survivability of the aircraft, since no protection was provided for them.
A minor problem also arose with the engines. It was not possible to use the in-line motors of the MV family (UT-3 was installed by MV-6A and MV-31F), since their production was discontinued in 1941. The choice remained for the radial motors M-11F and M-12. After comparison, it was concluded that the use of M-11F would be the most acceptable option. This motor did not differ much power, but was reliable, easy to operate and well mastered in mass production. To speed up the process of mass production, the wheels of the chassis, electric and pneumatic systems were borrowed from fighters.
In its final form, the new transport aircraft looked like the I-19, but it looked a little less elegant.
In May 1942, the Yakovlev Design Bureau received an official order to build a prototype, the assembly of which was completed in August at plant No. 47 in Orenburg. The prototype was immediately delivered to Moscow, where its tests began in the presence of the top aviation leadership. An experienced test pilot Shiyanov, who had considerable experience in mastering the new technology, was invited to test the prototype of the prototype. Within a few weeks, the experimental Yak-6 underwent an incomplete test program, which did not prevent making a completely favorable report on the capabilities of the aircraft - that the Yak-6 is easy to manage, can take off and land from any airfields, as well as carry bulky cargo, which was especially important in front-line conditions. Therefore, at least 10,000 such aircraft should be built and thus solve the problem with light transport aircraft. The report on the same day was presented personally to Stalin, after reviewing which was followed by an order to immediately launch the production of the Yak-6 in three factories at once.
Naturally, the main production of the Yak-6 unfolded at the plant number 47, where they built the first prototype. Until that time, the factory had launched production of UT-2 training aircraft, and at the end of 1941 it was planned to produce M-105P fighter jets at its facilities. Yakovlev, however, made significant adjustments to these plans. Since in October, there was a shortage of wood and instrumentation equipment, the UT-2 assembly plan was disrupted. With the Yak-1, even greater difficulties arose, since its design was mixed and radically different from the training aircraft.
At the request of the People's Commissariat of the aviation industry, it was necessary to start the production of the Yak-6 as soon as possible, at the same time without slowing down the production rates of the UT-2. In fact, there was no time to master the production of the Yak-6, and in September, Plant No. 47 began to manufacture the components of the aircraft. In November, the first production copies of the Yak-6 were ready, immediately heading for the front. At the same time, under the release of the Yak-6 allocated plant number 464. Previously, gliders A-7 were produced here, but in the summer of 1942 this company was reoriented to the production of the multi-purpose Yakovlev aircraft. From August 1943, the plant also carried out repairs of damaged aircraft.
The built airplanes were not reduced to any separate aviation units, but were distributed among regiments and squadrons. The first Yak-6 began their career as courier aircraft in the central sector of the front. Quite a few of these cars were at Stalingrad, however, it quickly became clear that the Yak-6 does not match the declared characteristics. As it turned out, a pilot with a qualification not lower than average could fly the plane. Especially tough problems with the aircraft appeared at full load, when the centering changed and the Yak-6 could only be lifted by a very experienced pilot. In addition, the Yak-6 could not carry cargo of a total weight not exceeding 500 kg - less than gliders of type A -7 or G-11, which suited the aviation command altogether.
In 1943, Yakovlev began to refine the aircraft, making the main emphasis on improving flight performance. To do this, one of the serial Yak-6 was tested ["blown"] in the TsAGI wind tunnel, and after a few months they began to build modernized aircraft. The most advanced of them, the third prototype, which received the designation Yak-6M, had fairings on the engine cylinders, increased vertical tail, as well as increased V-shape and sweep of the wing. Although the handling of the Yak-6M was improved, according to the rest of the data, it remained at the same level. As a result, the release of the Yak-6 quickly turned. One of the reasons for this step was the appearance of the Szhe-2 aircraft designed by Shcherbakov, whose production was established at the end of 1943.
The final attempt to improve the aircraft was the appearance of the Yak-8 variant. This modification differed in the increased geometrical sizes, in essence being the processed Yak-6M. Tests were conducted in 1944.
Meanwhile, the operation of the Yak-6 continued. At the beginning of 1943, the airplanes arriving at the front were actively used for their intended purpose - as courier and communications. Soon, the Yak-6 was attracted to flights to the rear of the enemy, to partisan airfields. Like other types of aircraft, “Yaks” delivered weapons and food to the partisans, while several aircraft were lost after landing on unprepared airfields.
When it became clear that a good light transport aircraft could not be obtained, the idea arose to apply the existing Yak-6 for another purpose. In the same 1943, the Yak-6NBB variant appeared - a night bomber at close range. The changes included the installation of bomb racks, designed for five 100-kg or two 250-kg bombs, and defensive armaments, consisting of one 7.62-mm SHKAS machine gun. The crew of the aircraft has not changed, so the shooting from a machine gun had to lead the navigator. The plane was also equipped with a radio station and the PKK, and special manifolds were placed on the exhaust pipes to exhaust the aircraft in the night sky.
The outer suspension of the bombs and the machine-gun installation, in addition to the increase in take-off weight, worsened the flight data of the aircraft compared to the previous machine, in which the cargo was placed in the fuselage. The run-up increased significantly (up to 410 meters), and the take-off distance reached 1260 instead of the specified 1000 meters.
Although it is quite often possible to find statements that the combat use of the Yak-6NBB was successful, in fact this turned out to be far from the case. The bombing at night was not particularly accurate, and the lack of offensive small arms made it almost impossible to finish off the enemy. In addition, in the battle against the fighters, the crew of the Yak-6NBB had practically no chance to get out alive. At the end of the war, another assault variant, the Yak-6, appeared, equipped with a battery of 8-10 RS-82 missiles. Such a "flying Katyusha" could bring great damage to the enemy, but only under one condition - the absence of air defense. As a result, assault Yak-6s were used very limitedly.
In the post-war period, the Yak-6 continued to serve in the Air Force for some time, but like the Sche-2, their career fully ended in 1947.
|Type||light military multi-purpose transport aircraft.|
|wingspan||14 m (45 feet 11 inches);|
|length||10.35 m (33 ft 11 inches);|
|wing area||29.6 square meters (318 square feet).|
|Weight||equipped - 1433 kg (3159 pounds);|
|Mass normal take-off , kg||2350|
|maximum take-off||2500 kg (5512 pounds).|
|Powerplant||two star-shaped piston engine M-11F|
|Power, hp||2 x 140 / 104 kW|
|maximum speed||230 km / h (143 miles / hour);|
|Cruising speed, km / h||185|
|practical ceiling||3380 m (11090 ft)|
|range||580 km (360 miles) / 900 km|
|Join the GlobalSecurity.org mailing list|