The Soviet Yakovlev Yak-7
was developed from the earlier Yak-1 fighter
, initially as a trainer
but converted into a "heavy" fighter. As both a fighter and later reverting to its original training role, the Yak-7 proved to be a capable aircraft and was well-liked by air crews.
Design and development
In 1939, Alexander Yakovlev
designed a tandem-seat advanced trainer, originally designated "I-27" and then "UTI-26", offered along with the original I-26 proposal that became the Yak-1. The "UTI" (Uchebno Trenirovochnyi Istrebitel, translated as: Training Fighter) was intended to give pilots
-in-training experience on a high-performance aircraft before transitioning to a fighter. With development work stated in 1940, the UTI-26 differed from its predecessor in its larger span wing being placed farther back for balance
as well as having two cockpits
with dual controls and a rudimentary communication system. It was armed with a single ShKAS 7.62 millimeter machine gun
in the cowling
, mainly for use in training, but Yakovlev envisioned a multi-purpose aircraft that could also undertake courier and light transport duties at the front.
The first production aircraft known as Yak-7UTIs retained a retractable main landing gear, but beginning in the summer of 1941, a fixed landing gear variant, the Yak-7V (Vyvozoni for Familiarization) was substituted. The factory reasoned that production would be simplified and that reduced performance would not be detrimental for a trainer. Yak-7UTIs and Yak-7Vs were also equipped with skis for winter operations.
A factory team, on its own initiative, converted an early Yak-7UTI into a "heavy" fighter, with two ShKAS 7.62 millimeter machine guns in the cowling, a ShVAK 20 millimeter cannon firing through the prop spinner and underwing racks for six RS-82 rockets. An armored backrest was added to the pilot's seat as well as armored fuel tanks were fitted. The rear cockpit position was retained, allowing it to accommodate a second seat (without controls) for fast courier and transport duties or a fuel tank for extended range. The additional space could also house bombs or other gear. Although Yakolev did not like the "hybrid" at first, the Yak-7 fighter proved to be very similar to the Yak-1 in overall performance although not as maneuverable. With a "go-ahead" from the Soviet Air Force, the Yak-7 was introduced into the production line and the first batch of 60 reached operational squadrons by the end of 1941.
The Yak-7 proved to be an effective close support fighter although the first two-seaters were considered nose-heavy, consequently, the factory introduced a rear cockpit fuel tank. Pilots complained about the fuel tank's vulnerability since it was unarmoured, and it was usually removed in the field. There were constant changes to the design based on combat observations including a definitive single-seat variant, the Yak-7B which was produced in large numbers.
After the war, some Yak-7V trainers were provided to the Poles and a single Yak-7V was delivered to the Hungarians for familiarization with the Yak-9 fighter.
: two-seat prototype converted from a pre-serial I-26Yak-7
: two-seat training, liaison aircraft. The Yak-1 was built in small numbers. Yak-7UTI
: initial two-seat communication/trainer versionYak-7V
: (UTI-26, vyvoznoy
) production version of two-seater; about 1,500 were built.Yak-7A
: production single-seat fighter version with M-105P piston engineYak-7B
: upgraded version of Yak-7A (reduced wingspan, simplified landing gear, better equipment), about 5000 were built.Yak-7D
: long range prototype.Yak-7K courier
: VIP transport version. converted from Yak-7B. 1944.Yak-7U Mark
: experimental - had two DM-4 ramjet
under wings. Two were built.Yak-7DI
: direct predecessor of Yak-9
: - new (M-82) engine version. tested in 1941.Yak-7R
: Jet project with one liquid fuel jet and two ramjets
: purported jet version of Yak-7 with Jumo 004
engine. Said to have been built in Tbilisi to fly over Red Square at the parade in 1947.Yak-7R
: Yak-3 with Jumo 004
turbojet. Development started not later than 1945
. First flown in 1946? Yak-7T
: two aircraft for testing engine mounted heavy cannons (NS-37 and NS-45 -- 37mm and 45mm caliber respectively).
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