Date: 2024-08-16 Page is: DBtxt003.php txt00017277
Engineering and Technology
Aircraft
Was the relative crudity of the MiG-25 a surprise to the U.S. Air Force once they had a chance to look at it after the 1976 defection of the Soviet pilot in Japan?
Peter Burgess
Fact: There was nothing “crude” about the MiG-25. The Western analysts who had a quick look at the aircraft were shocked by the unusual solutions Mikoyan applied to the kinetic heating problems that had plagued other trisonic aircraft (like the A-12/SR-71).
He rejected titanium as an uneconomic main material for the aiframe (despite the USSR being the world’s top producer of titanium) and the use of fasteners that required holes (drilling bits would start losing dimensions after a couple of holes in titanium, as Skunk Works found out on the A-12, also built with Soviet titanium “imported” by the CIA :-).
Thus Mikoyan decided to use spot welded high temperature steel. It worked. It still works today on the MiG-31. But to the western analysts who first saw it, the shock led them to explain it with our usual arrogant Cold War cliche of Soviet backwardness, and this, in turn, to the propagandistic spread of the term crude still in use today.
Fact. The MiG-25 was originally designed as an interceptor against the XB-70 trisonic bomber but entered service as a long range, high altitude, high speed interceptor and recce platform. It became the fastest, highest flying combat aircraft in service in history. Around 25 versions and over 1000 were built . Crude?
Fact. The MiG-25 was not based on the F-15. It was the other way around. The 25 first flight took place 8 years, 4 months and 23 days (1964) before the F-15 took off the ground (1972). The MiG-25 was the first fighter aircraft with a four-post empennage (two fins and two stabilators on one fuselage); but Mikoyan said he did not invent it. He credited a wind tunnel small test model of the North American A-5 Vigilante he was shown during a technical visit. The A-5 designers conceived the idea to reduce the height of the fin to fit aircraft carrier hangars (not “hangers”, btw :-)). Mikoyan adopted it for aerodynamic reasons: to keep directional stability and control at high angles of attack because his very wide fuselage would have obscured a single central fin. NA settled for a single, very tall foldable fin, after building a full sized mock-up of the twin finned model.
(A-5, father of the four-posts idea. Photo from Russian Journal “AviaMir”)
The F-15 adopted not only that, but in general, opted for an overall configuration closely resembling that of the MiG-25 (shoulder wings, rectangular wedge air intakes). It would be stupid to imply that its designers copied anything. They simply concluded that, for their purposes, that was the optimal configuration and they adopted and adapted it to their particular specifications.
That the F-15 looks a bit like a handsomer MiG-25, doesn’t mean it is a copy, as we would have said if it were the other way around. It only means that the 25 hit an optimal aerodynamic solution for twin-engined fighters and others adopted it: F-14 F-15, F-17, F-18, F-22, F-35, MiG-29, Su-27, Su-47, Su-57.
All SUVs and F1 Race cars look almost the same. None is a copy of any other. Like all our fridges and running shoes.