MiG-25 FOXBAT - Design
The MiG-25P is rightfully considered a revolutionary machine today. First of all, an aircraft design has been created that allows overcoming the "thermal" barrier, i.e. long-term flight at high supersonic speed, a stainless steel welded structure has been developed that provides high weight efficiency, maintainability, high manufacturability, stability of production due to automation, high material utilization rate, a combat complex has been created to effectively intercept all types of air targets. For the first time, a program climb was introduced, allowing flight along a given route, landing approach, bringing to the horizon, limiting in automatic and semi-automatic modes, and warning about reaching the speed limit.
The MiG-25 had the characteristics of an aircraft designed for intercepts at extremely high altitudes and speeds. It had speed and altitude characteristics in excess of any aircraft then operational in the world with the notable exception of the U.S SR-71. Although there was an initial argument in the West that such a capable aircraft would be assigned to an air superiority role with Frontal Aviation, it since became clear that the MiG-25 in its interceptor version has been deployed with the APVO. A high-speed reconnaissance version was deployed with Frontal Aviation.
It is noteworthy that there appeared to have been no competing aircraft prototypes associated with either the Su-15 or the MiG-25 requirements. The tradition of design competition was much in evidence in 1967 with respect to variable-geometry wing and VSTOL aircraft, but the two PVO aircraft were evidently developed in complementary, non-competitive programs. Competitive designs were abandoned before prototype construction — possibly at the stage of design approval or mock-up.
The MiG-25 closed a significant gap in aircraft performance between the mainstream of Soviet fighters and the performance of long-range interceptors. Since WWII each successive generation of Soviet fighters had demonstrated increased speed and altitude compared to its predecessor. The YAK-25, in 1955, departed from this overall trend, however. It represented a distinct sacrifice of performance to gain range and to accommodate the bulky accouterments of an all-weather capability. Successive modifications of the Yakovlev aircraft maintained this trend while the Tupolev fighter epitomized it. The MiG-25, however, represented a merger of the two trends of development. It apparently signified the increased importance of range and avionics equipment. Likewise it represented heavier designs required for higher and higher speeds. Meanwhile improvements in propulsion technology provided engines which allow heavier aircraft to achieve higher speeds and altitudes.
MiG-25 production was notable for its leisurely pace and lack of impact on the industry. During the 1960s one plant, Novosibirsk 153, provided the majority of PVO aircraft during the decade. Only the Tu-128P, of a size comparable to a bomber, was produced in facilities which accommodated other Tupolev bomber and transport activities. The MiG-25 departed from the pattern of Novosibirsk production for PVO; it was manufactured at Gorkiy plant 21 which had produced only, Mikoyan aircraft since 1948. Meanwhile, at Novosibirsk, a tactical fighter, the Su-19 (Fencer) started production to maintain that plant’s tie with Sukhoi.
The wings are high-mounted, swept-back, and tapered with square tips. The aircraft has two turbojet engines and large rectangular air intakes below the canopy and forward of the wing roots. There are dual exhaust. The fuselage is long and slender with solid, pointed nose. The aircraft is box-like from the air intakes to rear section. It has a bubble canopy. On the tail are twin, sweptback, and tapered fins with angular tips. There are flats mid- to low-mounted on fuselage, swept-back, and tapered with angular tips.
Assemblies of the airframe of aircraft MIG-25 include the fuselage, wings, keels, stabilizer, pylons, nose fairing. The MIG-25 is a one-place supersonic fighter, capable of carrying out flight with a velocity of 3 000 km/h and of accomplishing energetic (with the overload to 4,5 units) maneuvers in the range of the velocities of 2500-3000 km/h. Aircraft has two engines R -15 of the construction of OKB S.Tumanskiy with the thrust 11000 kg each. On the aircraft MIG-25 since 1965 on 1978 were established twenty five world speed records, height and rate of climb. The basic special features of the aerodynamic layout of this aircraft were: the wing of the moderate sweepback (41 deg), of the small relative thickness; flat off-axis inlets in combination with the wide lift fuselage; the double-keel diagram of vertical tail assembly; the differentially controllable stabilizer, which ensures the high efficiency of lateral control in flight with the high speeds. The kinetic heating of construction at the high flight velocities determined the selection of material - high-temperature high-temperature (strength) steels. The fuselage of the aircraft is of all-welded construction high-temperature (strength) stainless steel of the type VNS-2, VNS-SHCH, etc.
The wing of 3- longeron construction, is sectional on the joint with the nose tank and is nondetachable on the joint of nose tank with the central tank also of central tank with the trailing section of wing. Nose from OT -4 of all-welded construction. Nose and central tanks - tank of all-welded construction from VNS-2 and VNS-SHCH, power packs - made of steel E0KHGSA. Aileron and the flap of riveted construction with the application of honeycomb blocks. Pylon (APU-YA0, APU-YA0D) of riveted construction with the pintle suspension to the wing. Load-bearing elements - made of steel E0KHGSA, guides of pylon have chromium coating. Skins and structural elements are made from materials D -16, D -19.
Long range, high turning rate, ground target acquisition, look-down radar, and large ordnance payload and delivery capacity could be ignored. Advanced electronics, exotic materials, precise manufacturing techniques, and complex structures were not required. Stainless steel and aluminum were the primary airframe materials instead of the more expensive and difficult-to-handle titanium or synthetic materials. Rivets were left unground (except in aerodynamically critical areas), and welding was crude, but adequate. The resulting heavy structure and drag penalties were dealt with by powerful fuel-hungry engines and by large fuel tankage.
Most importantly, the Soviets accepted the aircraft's limited range and payload. At other than the high-altitude, high-speed design point, performance was significantly degraded. Its ANAB air-to-air missile was used earlier on the Tu-28 (Fiddler), and the ejection seat, Cockpit instruments and engine were off-the-shelf hardware that had been used in the MiG-21 and earlier aircraft. The avionics, for the most part, made use of vacuum tubes.
The radar, though based on a technology that is out-of-date by American standards, was one of the most powerful ever seen in an aircraft and therefore less vulnerable to jamming. The number of cockpit instruments were about half those used on the same vintage American F4 and the cockpit layout and instruments were adapted from the MiG-21. Extensive use of ground control for interception considerably reduced the need for on-board aircraft systems.
Through the use of proven technology, the designers achieved a high degree of reliability. American aerospace analysts describe the MiG-25 as "unsurpassed in the ease of maintenance and servicing" and a "masterpiece of standardization."
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