The Soviet Union’s Efforts to Deploy an Operational Vertical take-off Combat Aircraft
By:
Raul Colon
E-mail: rcolonfrias@yahoo.com
PO Box 29754
Rio Piedras, Puerto Rico 00929

Yak 36

The Soviet Union’s efforts to develop and eventually produce an operational Vertical Take-Off and Landing Aircraft (VTOL) had its roots in the early 1950s, but it wasn’t until Aleksandr Yakovlev visited the renowned Farnborough Air Show in September 1960 that interest for this type of aircraft gathered the necessary support in the upper echelons of the Soviet government to push a major programme forward. While attending the show, Yakovlev, was particular awed by the flying capabilities of the Short SC1 VTOL demonstration aircraft. In fact, he was so impressed that on his return to the Soviet Union, he directed his top two engineers, LM Shekhtyer and VK Tsvelev, to design a preliminary concept for a Soviet VTOL plane.

They immediately went to work on the project. The basis of the design was the highly manoeuvrable and successful Yak-30 training aircraft. Soon, they were producing mock-up designs and drawings, unfortunately, the project was concluded because, and Yakovlev OKB resources were needed on the Yak-36 program. Although the project was officially terminated, interest in the concept never subsided.

On October 30th, 1961; the Soviet Union’s Council of Ministers issued a Directive ordering the Yakovlev Design Bureau to commence work immediately on the design and development of a single seat, twin engine VTOL fighter-bomber aircraft. The two main design specifications was that the VTOL should carry a variety of free-fall bombs, including nuclear devices; and that it could reach speeds of up to 746 miles per hour. The first design Yakovlev presented was the Yak-36 research plane. Originally, the Yak-36 was intended to use two R21M-300 engines capable of generating 11,025lb of thrust; but a newer and more elaborate engine design came along: the R27V-300, which could provide the aircraft with 11,685lb of thrust. The Yak-36 fuselage was very similar to that of the Mig15 series of planes but with a major modification. The airframe was fitted with vectored thrust nozzles designed to provide the aircraft with a major lift capability.

Yak 36 'Freehand'

Four units were eventually produced, the first sample taking to the air on January 9th, 1963. The first series of test flights were intended to prove the frame’s airworthiness. The 36’s performed flawlessly. Then, on the morning of September 16th, the Yak-36 made its first full transition into horizontal operation. The test was a resounding success in that it demonstrated to Soviet leaders that VTOL operations could be achieved by its engineers, but the reality was that the 36’s underperformed in all its transitions tests. One sample of the Yak-36 made an unexpected appearance over Domodedovo in July 1967 causing much concern to Western military leaders whom promptly codenamed the aircraft the Freehand. Soon afterward, the complete programme was phased out in favour of the Yakovlev Yak-38. The Yakovlev OKB used much of the 1960s performance research and evaluation on the technical difficulties of VTOL operations, especially on the difficulties of lift to cruise transition.

They planned to utilize a combination of power plant. Of lift-to-cruise engine fitted with two rotating nozzles augmented by a separate vertically mounted lift jet originally designed by the Kolesov OKB. Although by this time there growing doubts in the Soviet high hierarchy about the feasibility of a VTOL operational system, the Soviet Aircraft Industry Minister, Pyotr Demetiev, proceeded to give the operational go-ahead order to the programme with the caveat that the complete program be subdivided. The original Yak-38 program was subdivided into two major concept development projects. The first of these was the already produced Yak-36 light attack aircraft. The selected 36 sample would be fitted with a new state of the art avionic system to provide the OKM research data on the in-flight controlling mechanisms. The next phase, or other part of the program, called for the development of a supersonic fighter, codename Yak-36P. That program never made it off the drawing board.

Yak-36 "Forger"

But with all the research data collected, the Soviet Air Force still was not convinced that an VTOL operational aircraft could be developed. Here’s where the Soviet Navy intervened. They clearly saw the advantages of a VTOL airplane. They saw the VTOL as the final piece in their scheme to build and operate aircraft carriers. At the time, Project 1143 or the Kiev Class vessels, the Soviet Union first true attempt at fielding an operational aircraft carrier; was being developed. This decision by the Navy saved the Yak-36 program and in November 1967 the council of Ministers gave the official notification to proceed with the program.

On January of the next year, the Air Force, reluctantly, ordered Yakovlev to proceed with its research. The initial Yak-36 form started to develop in late March 1968. A final mock-up design was examined in mid April 1970 and the first of four sample units made its first hover flight test on September 22nd, 1970; it transitioned to conventional flight on its fourth flight test in December 2nd. On the afternoon of November 18th, 1972, the first prototype made the programme’s first landing on a warship, when it landed on the deck of the helicopter carrier Moskva. More testing followed until the Yak-38 was deemed operational in the spring of 1976. It reached operational status the following October.

While on operational service, the Yak-38, as it is the case with many advance aircraft designs, experienced many mechanical problems. A major attempt was made to correct the aircraft avionics and mechanical systems in the mid 1983, with the introduction of Yak-39 fighter-bomber design. The 39 were to be basically a 38 airframe with a larger wing fitted with flaps and leading edge slats that could be adjusted to three angles, plus, a modified tail that gave the 39 the ability to carry more weapon systems.

Yak-38

The original 38 could take off with a maximum weight of 11,300lbs; the newer version could add four hundred more pounds of ordinance. The 39 was powered by a single R28V-300 lift-cruise engine capable of generating 14,770 pounds of thrust. Swivelling nozzles were also installed, this system was augmented by two 9,040lbs of thrust RD-48 lift engines. Another refinement was the radar system. The new 39 housed an S41D radar scanner located on a large radome cover. For close quarters protection, the aircraft was fitted with a 30mm cannon. Maximum speed for the 39 was 559 miles an hour at low level, while its maximum operational range was a limited 280 nautical miles.

A special commission was assembled to discuss the Yak-39 concept in July 1983. The commission rejected out of hand the concept because of its limited range, combat durability and mechanical problems. Further development of the 38 was officially abandoned in September 1983. Later in the 1980s, Yakovlev presented a concept idea for a supersonic VTOL fighter, codename yak-41; of which two prototypes were eventually built and tested for Soviet Navy operations. They did not offer any major improvement over the original 38 and were discarded before the project reached production capability. A mild attempt was made for a muli-role VTOL aircraft in the late 1980s, but this idea did not even make it out of the planning stages. Time was running out for the Soviet Union. They were never able to deploy a fully functional VTOL aircraft such as the vaunted British Harrier Jump Jet.