MiG-15 Experimental Versions

Design Bureau: In most cases, the OKB-155 ofAI Mikoyan.

Made possible by Britain’s export of Rolls – Royce Nene turbojets to Moscow in Septem­ber 1946, the Aircraft S marked a dramatic leap forward in Soviet fighter design. First flown on 30th December 1947, it was far ahead of any other fighter in Europe. In 1949 it went into large-scale production as the MiG – 15. In the Korean war (1950-53) it completely outperformed Allied aircraft (the F-86 was the only rival in the same class) and put the name ‘MiG’ in the limelight around the world, where it remains to this day. A total of 11,073 of all versions were constructed in the USSR, and the global total exceeded 16,085 (the Chi­nese output is not known precisely). Many have served in experimental programmes. These, and other MiG types, require treat­ment that is not apposite in the context of this book. What follows therefore is the specifica­tion for a typical standard late production ver­sion, the MiG-15b/s, incorporating numerous aerodynamic, control, systems and engine improvements overthe original MiG-15. Much more detail of experimental MiG-15s will be included in an Aerofax on the MiG-15 which will be published in 2001. The engine of the MiG-15b/s was the VK-1, derived from the Nene and rated at 2,700kg (5,952 Ib).

su

One of the experimental versions of the basic (not £>/s) aircraft was given the OKB designa­tion SU. Originally a standard fighter, MiG-15 No 109035, with callsign 935 painted on the fuselage, it was used to test the V-I-25/Sh-3. This was the designation for a fighter arma­ment system developed by the Shpital’nyi weapons bureau. The standard quick-change armament pack housing one 37mm and two 23mm guns was replaced by a fixed installa­tion of two powerful Sh-3 23mm guns, each
with 115 rounds. Each gun was mounted below the fuselage in a streamlined fairing. The barrel projected through a vertical slot so that, mounted on trunnions and driven by an irreversible electric screwjack, it could be el­evated to +11° and depressed to -7° (there was no lateral movement). The Ministry order for this conversion was signed on 14th Sep­tember 1950, and the SU was factory-tested between 2nd January and 27th March 1951. NIl-WS testing followed from 30th June to 10th August 1951. The general opinion was that in tight turning combat the system was useful in bringing the guns to bear, and it also enabled a head-on attack to be made with less risk of collision. The NIl-WS report called for a better sight, and for the guns to pivot over a greater angular range.

SYe

Written SE in Cyrillic characters, this was a tangible result of years of research into the endemic problem of poor or even reversed lateral control, wing drop and inadequate yaw (directional) control, especially at high Mach numbers. Most of the research was done at CAHI (TsAGI), but two workers at LIl-MAP (the Ministry flight research insti-

tute), I M Pashkovskii and D I Mazurskii, also took a hand. After various tests they made recommendations to AI Mikoyan, who or­dered the OKB to construct two SYe aircraft, based on the MiG-156/s. An obvious modifi­cation was that the fin leading edge was kinked to maintain a, broad chord to the top. Among other changes the wings were stiff­ened and fitted with ailerons of higher aspect ratio ending in square tips. The first SYe, call­sign 510, was assigned to LIl-MAP pilot D M Tyuterev, who dived it to Mach 0.985 despite having unboosted ailerons. The ailerons were then fitted with BU-1 boosters, whereupon on 18th October 1949 Tyuterev dived it to beyond Mach 1, the first MiG aircraft to achieve this.

Burlaki

One ofthe deeper problems of the Soviet ADD (Strategic Aviation) was how to escort the Tu-4. No fighter, especially a jet, had anything like adequate range. Aircraft designer A S Yakovlev suggested making the bombers tow fighters to the target area (see Yak-25E). Mikoyan briefly worked on a similar Burlaki (barge-hauler) scheme, fitting a MiG-155/s with a harpoon clamp above the nose which the pilot could hook on a crossbar on the end ofa long cable reeled out from the Tu-4. Ifhos- tile fighters were encountered the MiG pilot would start the engine, release the tow and en­gage combat. In theory he could then hook on
again for the ride home. It was not considered a viable idea, one reason being that with the engine inoperative the MiG pilot had no cock­pit pressurization and also became frozen.

Refuelling test-beds

An alternative to the Burlaki method was Dozapravka v Vozdukhe, refuelling in flight. Extensive trials took place in 1949-53 using
various MiG-15 s and Tu-4 tankers. Eventually a system was used almost identical to that de­vised by the British Flight Refuelling Ltd, with hoses trailed from the tanker’s wingtips and a probe on the nose of the fighter. Apart from the basic piloting difficulty, problems includ­ed probe breakage, pumping of bulk fuel into the fighter’s engine and the need for an im­proved beacon homing method for finding the tanker at night or in bad weather.