Yakovlev Yak-15

Le jet soviétique sur Wikipedia; version anglaise :

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The [Vous devez être inscrit et connecté pour voir ce lien] Yak-15 ([Vous devez être inscrit et connecté pour voir ce lien] "Feather") was one of the first [Vous devez être inscrit et connecté pour voir ce lien] aircraft to be tested and go into production.

Along with the Swedish [Vous devez être inscrit et connecté pour voir ce lien], it was one of very few jets to be successfully converted from a piston-powered production aircraft.

A Yak-15 was also the first Soviet jet aircraft to be successfully refueled inflight.

History

The Yak-15 was one of several aircraft designs to emerge from the [Vous devez être inscrit et connecté pour voir ce lien] following a request from the [Vous devez être inscrit et connecté pour voir ce lien]
in February 1945 to begin designs of jet aircraft.

It should be noted that this request came two years after the introduction of jet fighters in [Vous devez être inscrit et connecté pour voir ce lien], and nearly a year after the January 1944 introduction of jets into the U.S. military.

Development and testing

Though the engine design firm of Lyul'ka was making progress in developing a Soviet designed jet engine, Stalin announced that as a temporary measure the German [Vous devez être inscrit et connecté pour voir ce lien]B and [Vous devez être inscrit et connecté pour voir ce lien]A jet engines would be built in the Soviet Union until an indigenous design was ready, these engines being designated the RD-10 and RD-20 respectively.

[Vous devez être inscrit et connecté pour voir ce lien] began development of a twin jet aircraft of a design similar to the German [Vous devez être inscrit et connecté pour voir ce lien], while [Vous devez être inscrit et connecté pour voir ce lien] pointed out that the thrust of the Jumo 004B was well-suited to the existing Yak-3 fighter, and was instructed by the Kremlin to begin a crash program of designing and building such a conversion.

The development of the Yak-15 was assigned to Yakolev designer Ye G Adler, assisted by Shekhter, and they presented the first three-view sketches just three days later.

Further drawings were issued to the [Vous devez être inscrit et connecté pour voir ce lien] experimental factory in late May 1945.

Despite the dramatic change in engines, no real difficulties were encountered, and the loaded weight of the Yak-15 was actually found to be less than that of the Yak-3.

To expedite development, existing drawings were used of the Yak-3/VK-107A for the all-metal rear fuselage, horizontal tail, and main undercarriage, as well as for most of the wing.

The front of the welded-tube fuselage truss was considerably modified to carry the Jumo engine, which was hung underneath on rubber shock-absorbing mounts.

Though the engine was inclined 4 degrees 30' nose-up, the skin under the rear fuselage near the jet exhaust was of KhGSA chrome steel.

The tailwheel was also fabricated out of steel, and lacked a rubber tire.

It was protected by a small fairing which also served as the undercarriage door when retracted.

The vertical tail was slightly enlarged and skinned in D1 metal, as was the heavily modified nose cowling surrounding the engine, which retained a Riedel two-stroke piston engine starter in the nose 'bullet'.

The wing spars were strengthened, and the front spar was curved in an arch over the engine.

A third fuel tank was also installed above the engine.

Armament was intended to be the traditional single ShVak cannon, plus two [Vous devez être inscrit et connecté pour voir ce lien] machine guns.

The prototype was hand-built with utmost urgency and was flight-ready in October 1945.

At the testing facility at [Vous devez être inscrit et connecté pour voir ce lien] the aircraft was put through taxi tests by OKB test pilot Mikhail I Ivanov. Strangely, this was not immediately followed by flight testing, despite the urgency placed on the project by the Kremlin.

Instead, the aircraft was transferred to the large CAHI wind tunnel, where it was tested until April 1946, often with the engine running.

This delay allowed the prototype of the Yak's main competitor, the [Vous devez être inscrit et connecté pour voir ce lien], time to be completed and prepared for
flight testing as well.

Official Kremlin accounts state that the delay was due to "inclement weather", while Yakolev claims that the reasons
were purely political.[Vous devez être inscrit et connecté pour voir ce lien]

Once the rival MiG-9 prototype, the MiG-I300, arrived at Zhukovskii, the flight testing was allowed to commence.

On 24 April 1946, following the toss of a coin, the MiG made the Soviet Union's first jet flight, with the Yak flying three hours later.

Flight testing proved completely trouble-free, and both prototypes were publicly displayed at Tushino Aviation Day on 18 August 1946.

Early in testing the Yak-15 had been found to be an excellent design, and was ordered into production even before NII-VVS testing was completed in May 1947. Gen P M Stefanovskii did many of the test flights himself, and was delighted with the aircraft's handling, commenting that it was the world's lightest and cheapest jet fighter, but in no way inferior to heavier types.

After going into production, a number of Yak-15s were modified for special research and experimental programs (see "Variants" below).

These include the first Soviet jet to be successfully refueled inflight, using a looped hose connected to the starboard wing.

Production

The contract for production of the Yak-15 was awarded to Factory No. 31 at [Vous devez être inscrit et connecté pour voir ce lien], and was a direct follow-up to their Yak-3 production. [Vous devez être inscrit et connecté pour voir ce lien] ordered that twelve Yak-15s and twelve MiG-9s should participate in the revolutionary parade in October 1946.

This delayed production, as the proper tooling was not yet ready, and these aircraft had to be hand built.

The twelve aircraft were completed on time, with the first of this special batch being test flown on 5 October, and the last by the end of the month, though ultimately the flypast was cancelled because of fog.