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Further Reading

Ye-8 (MiG-21M, MiG-23)

The original designation for the new Ye-8 next generation MiG fighter (aka E-8 because of the pronunciation of the Russian letter "E") was MiG-23. 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.

Two prototypes (Ye-8/1 and Ye-8/2) were built in 1962. They resulted from a Kremlin decree calling for a version of a MIG-21 capable of destroying hostile aircraft at night or in bad weather. These prototypes differed in details from each other. It featured canard foreplanes and a redesigned rear of the fuselage to accomodate new engine. There were a number of other features that were different from MiG-21PF - from new ejection seat and canopy to modified rudder and new fin under the rear part of the fuselage. The R-21F engine developed by N Metskhvarishvili, was rated at 4500kg and 7000kg with afterburning. A variable-incidence canard spanning 2.60m was fitted - this having been earlier tested by a Ye-6T - and it was proposed to install Sapfir 21 radar to accompany an armament of two K-13 AAMs.

The first of two prototypes, the Ye-8/1, was flown on 17 April 1962, followed on 29 June by the Ye-8/2. On 11 September, the R-21F engine of the Ye-8/1 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. At this time, the Ye-8/2 had effected 13 flights, but the program was abandoned. The Ye-8 project was cancelled in 1963, but it served as testbed for testing new technologies for later generation of Fishbeds and also for MiG-23 Flogger, which had a longer range and a much better radar with side mounted air intakes and swing wings for rough field performance and high speed at low and high altitudes.

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.

One can find many aircraft in the history of domestic and foreign aviation that defined the level of perfection for their times. Some of them, unfortunately, were not further developed despite their highly promising tactical performance characteristics. This occurred for various reasons, chief among which was the absence of a reliable power plant. One of the original aircraft of the Mikoyan OKB, the Ye-8, which was by the intent of its creators to bear the name of MiG-23 in series production, did not escape a similar fate.

The outward appearance of the Ye-8 differed substantially from the standard look of the MiG-21, on the basis of which it was constructed. All preceding aircraft of this firm had a central, frontal air intake, but on this one it was located below, under the cockpit. The nose portion of the fuselage was faired, and was intended for the placement of a radar with a large-diameter antenna. There was still no radar, true, on the first experimental Ye-8/l and then on the second Ye-8/2. The installation of the new 8-23 intercept system, which included the Safir-23 radar and the R-3S air-to-air missiles, and later the R-23T, was planned. There was still no radar suitable for installation on the aircraft by the time of building of the first flight of the Ye-S, and the weight equivalents of it were thus installed in its place. The monitoring and recording apparatus and the telemetry unit were also accommodated in the nose portion along with the weight equivalents.

Small winglet side stabilizers were mounted along the sides of the nose portion of the fuselage. The wing, landing gear and empennage of this aircraft did not differ from the same elements ofthe MiG-2IPF design. The forward landing-gear strut, true, was somewhat altered in appearance -- it had a breakaway strut. There was one more feature that struck the eye -- a large fence (supplementary fin) was placed under the tail section of the fuselage. The fence was turned 90° when the landing gear was down, and it was opened after takeoff, significantly increasing directional stability in flight. The lowering and retraction of the fence was interlocked with the retraction and lowering of the landing gear. This very design was used several years later on the MiG-23 aircraft.

There was another innovation on the Ye-8, albeit invisible from the outside -- all of the fuel tanks in the fuselage were no longer rubber bag (insert) tanks, as on all the various modifications of the MiG-21. They were tanks of the design that later became widespread on all subsequent MiGs without exception. The Ye-8 could hold in all 3,200 liters of kerosene, in five fuselage tank compartments and four wing tanks (as on the MiG-21). The Ye-8, like the Ye-7, had a system for boundary-layer ejection from the flaps when landing. It had not been activated on either the Ye-8/l or the Ye-8/2, however.

One of the chief features of the aircraft, simultaneously with the new and progressive aerodynamic configuration, was the new, experimental R21F-300 engine with enhanced thrust. It was somewhat larger than its series predecessor, the R11F2S-300 on the MiG-21PF aircraft, in overall dimensions and weight. Its thrust with afterburners increased from 5,740 to 7,200 kgf. The degree of thrust augmentation for the new engine was quite high and reached 55 percent. The R21F-300 was designed and built at the motor-building OKB headed at the time by Chief Designer I. Metskhvarishvili. Many aviation designers placed great hopes on this twin-rotor engine -- which were not, unfortunately, later justified.

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.

The winglet in the nose portion of the fuselage had no control system at all, and was located in a wind-vane position in subsonic mode. When the aircraft reached Mach 1 the winglet was mechanically fixed in a neutral position relative to the axis of the aircraft. This altered the position of the focal point and reduced the reserves of longitudinal stability, which were excessive at supersonic speeds. The possibility of sustaining much larger G-forces at supersonic speeds was provided thereby. The Ye-8 aircraft actually could have become a fighter for maneuvering aerial battle as early as the beginning of the 1960s, such as the MiG-29 and the American F-16. The air intalke, located under the fuselage, was executed in a flat, dual-stream mode with a vertical three-position wedge with electrical / hydraulic control. A recess for lowering the forward landing-gear strut was located between the panels of the wedge.

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.

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 6the, at which the specialists in various fields gave the Ye-8 aircraft the green light. 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. 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 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.

The achievements of the Ye-S/l and Ye-S/2 included maximum speed of 2,230 kmlhr, Mach 2.1 and ceiling of 20,000 meters. These were excellent characteristics for an aircraft with a takeoff mass of just S,200 kg (the mass of the empty aircraft, by the way, was just 5,670 kg). The creation of the Ye-8 experimental fighter using the basic components that had already been put out in 1962 for the series-produced MiG-21PF aircraft was undoubtedly a progressive step in Soviet aircraft construction, which was, unfortunately, not completed due to the engine that had not been brought to the necessary level of reliability. Work was already underway at full speed at the OKB by that time on the design engineering of a completely new fighter, the MiG-23, with variable-sweep wings, which also influenced the decision to curtail all work on the Ye-8.

The MiG-21M, MiG-23, Ye-8 design had a superficial resemblance to the design of the Chinese Jianjiji-7 - J-7MF developed in the late 1990s, in that both feature a a chin inlet rather than a nose inlet, but otherwise the designs are entirely unrelated.