Mikoyan-Gurevich E-8 "MiG-23" - Program
Soon after the development of the Ye-6 and the start of mass production of these machines, receiving the name MiG-21, it became clear that the potential of this machine was truly inexhaustible and it could serve as a good basis for modifications. That is indeed what happened. The MiG-21 was actually modified a record number of times from 1959 to 1972. Modernization of MiG-21 aircraft was mostly towards installing new engines with increased thrust, increasing the supply of fuel on board and of equipment and armament. But the Ye-8 was substantially different from the standard MiG-21, with a new advanced aerodynamic design. The air intake was located under the fuselage, whichwas faired nose to accommodate the «Sapphire-23 " radar with a large-diameter antenna.
The Ye-8 aircraft was created by decree of the government of the USSR as a profound modification of the series produced MiG-21PF, but it had such innovation of design that it was decided to give it the future index of MiG-23 even in the initial stages. The Ye-8 - like the MiG-21PF - was intended for the defeat of targets in the forward and rear hemispheres in day or night and in good or bad weather conditions - that is, it was to be a multi-role, mass front-line fighter/interceptor. Aasemblies that had already been tried out on the MiG-21 were used for the rest of the Ye-S, which was to simplify the output of the future MiG-23 in series production with the parallel replacement of the MiG-21PF with MiG-23s on the conveyor line.
In 1959, the chairman of the state commission on MiG-21, Lieutenant General Ivan Pstigo (in the future air marshal) signed a preliminary conclusion on the test results with a recommendation to start mass production of a new front-line fighter MiG-21F. OKB-155 of the State Committee for Aviation Engineering (GKAT), led by General Designer A.I. Mikoyan, despite the enormous load associated with the start of mass production, has begun work to improve the performance and expand the combat capabilities of the aircraft. At the same time, work was underway at the Design Bureau to create “heavy” fighters designed to achieve high speeds (up to M max = 2.6-2.8).
The design stage of the project started in 1960 from the basis of a deep modification of the MiG-21PF. The most prominent new feature was the redesigned front part of the airplane, with Eurofighter-style jet intake under the cockpit. The nose mounted air intake restricted the size of the radar the Mig-21 could use. The Mig-21 didn't need big powerful radars. They were point defense fighters that took off and flew less than 200km and engaged enemy bomber aircraft and fighters or strike aircraft. They were vectored to their targets via ground radar installations.
The dimension of the fighter, which was originally called the MiG-23, was to be only slightly larger than the MiG-21, so that this aircraft replaced it in mass production. At the same time, it was supposed to equip the machine with a new generation weapon system, respectively named S-23. It was to include the Sapphire radar station and K-23 medium-range air-to-air guided missiles with semi-active radar and thermal homing heads. Therefore, in a decision of the USSR Council of Ministers Commission on Military-Industrial Issues adopted on May 30, 1960, it was prescribed to develop the MiG-23 based on the MiG-21PF using the S-23 weapon system. In mass production, he was supposed to replace the already well-developed MiG-21PF on the conveyor.
Two prototypes (Ye-8/1 and Ye-8/2) were built in 1962. These prototypes differed in details from each other. The assembly of the first prototype of the E-8 (E 8/1) front-line fighter, which received tail number 81, was completed in January 1962, and on March 2 it was transported to the OKB flight station at the LII aerodrome in Zhukovsky. Finalizing and adjustment operations were performed in a hangar and on the test-track site for more than a month. A methodological council was finally held on April 6th, at which the specialists in various fields gave the Ye-8 aircraft the green light.
The first of two prototypes, the Ye-8/1, was flown on 17 April 1962 by the chief pilot of the Design Bureau, followed on 29 June by the Ye-8/2. G. Mosolov made the first flight on 17 April 1962. The aircraft "went up," but it turned out that the R21F-300 engine was still not fully ready for flight testing. The first flight went without comment. Considering that the power plant and especially the engine caused certain concerns, in the second and third flights its starting qualities were tested. As subsequent events showed, checking engine starts was a very timely and necessary operation.
Specialists, including the leading test pilot of the firm, G. Mosolov, liked the aircraft. The crew was designated for the first experimental copy on 10 May 1962 by order of the Minister of the Aviation Industry: the lead pilot was G. Mosolov, back-up was A. Fedotov, the lead engineer was V. Mikoyan, and his assistant was V. Shcheblykin. The mechanic and engine mechanic were V. Kochkin and G. Spitsyn. The lead designer of the motorbuilding OKB, V. Vedenev, took part in the testing of the aircraft.
There were actually 11 engine stoppages on forty flights of the first Ye-S/l flight model, which were almost all preceded by a compressor surge -- a phenomenon not only unpleasant, but dangerous as well, for the pilot and the aircraft, since powerful lateral vacillations of the aircraft started therein. Mosolov flew the Ye-8/1 for 16 hours and 22 minutes. Seemingly not all that much, but there was more than enough unpleasantness with the engine.
The designers at the OKB headed by N. Metskhvarishvili had tried in every way possible to improve the too-small reserves of gas-dynamic stability of the compressor as early as in the process of flight testing. They replaced the guide vane apparatus of the compressor with a new one, they adjusted the moment of opening of the bleed band of the air from the compressor, they adjusted the automatic fuel system and, finally, the engine itself etc. They were, however, unable to raise the reserves of gas-dynamic stability of the engine, and it remained very sensitive to changes in modes at high speeds.
The E-8 tests were the last in the flight biography of the honored test pilot of the USSR Georgy Konstantinovich Mosolov, Hero of the Soviet Union, Colonel, author of three absolute world records of speed and altitude. The second instance of the E-8/2 fighter, which had an onboard - "82", took off for the first time on June 29, 1962.
On September 11, 1962, during a flight to disperse at an altitude of 15 km and a speed of M = 1.8, the disk of the 6th stage of the engine compressor exploded at Mach=1.7 at 10000m. It was subsequently ascertained that the sixth compressor stage fan had penetrated the engine casing and had then continued on to destroy the starboard aileron. Part of the disk, breaking away in acceleration (and the maximum engine speed was 11000-12000 rpm), like a cutter, instantly sawed through the engine body and the fuselage skin, followed by the destruction of both hydraulic systems and the fuel tank, causing loss of control and an airplane fire. wing in the aileron zone, it caused its destruction. The failure of the aileron in turn led to a helical (in a barrel) drop from a height of 15,000 m. A sharp decrease in engine thrust led to a powerful surge of the compressor and the air intake duct. In a spiral decline, the aircraft became virtually uncontrollable.
By September 4, test pilot Alexander Fedotov flying on it managed to make 13 flights - the accident E-8/1 forced to stop flights on this machine. At this time, the Ye-8/2 had effected 13 flights, but the program was abandoned. After analyzing all the negative phenomena, and mainly because of the need for capital decisions on the engine, the topic was closed, despite the good flight performance obtained on both aircraft. This was a voluntary decision of the leaders of the aviation industry, supported by the defense department of the Central Committee.
The flights in the second copy of the Ye-8 - the Ye-8/2 - were made by test pilot A. Fedotov. Thirteen flights were made in all. Flights in the Ye-SI2 were curtailed after Mosolov's accident and were not restarted, despite the good tactical performance characteristics obtained on both aircraft before the accident on 11 September 1962. This was an impulsive decision by the leaders of the aviation industry. The aircraft could doubtless have been brought to the necessary level of reliability.
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