What are the differences between the MiG 31 and MiG 25, they look exactly the same, their overall performance the same. Is it the roles they were built for are different?

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    $\begingroup$ According to the specs, the answer is: MiG 6 $\endgroup$ Commented Oct 4, 2016 at 18:38
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    $\begingroup$ Look the same?? All airliners look the same then! There are more similarities between A320 and B737 than between these MiGs. $\endgroup$
    – Zeus
    Commented Oct 6, 2016 at 6:25

2 Answers 2


The MiG-31 is an all new design with higher strength for low-level flight and new engines. The reason it looks just like the MiG-25 has to do with the structure of the Soviet aviation industry. The basic shape is first defined by the Central Aerodynamic and Hydrodynamic Institute (TsAGI is the abbreviation of its Russian name) and then given to the design bureaus which do the mechanical design. Production is then relegated to dedicated manufacturers which build the designs of different bureaus in parallel.

Both aircraft were designed as interceptors. The main difference is the advanced radar, digital data links and the more powerful engines of the MiG-31 which made a longer fuselage necessary. The MiG-25 radar, a development from the 1960s, could only detect high-flying targets, while the Zaslon radar of the MiG-31 can also detect and track low flying aircraft (look-down/shoot-down capability); a necessity after NATO changed its strategy to nap-of-the-earth flying to avoid detection.

If you need to tell both apart on pictures, look for these features:

  • While the main landing gear of the MiG-25 has a large, single wheel, the main gear of the MiG-31 uses two smaller wheels in a staggered arrangement.

MiG-31 main landing gear

MiG-31 main landing gear (picture by Burkhard Domke source)

  • While most MiG-25 were single seaters, the MiG-31 has two occupants, a pilot and a weapon systems officer behind him. Two-seater versions of the MiG-25 can be easily distinguished because the two cockpits are separate units, the front cockpit replacing the radar.

MiG-31 on the ground with canopies open

MiG-31 on the ground with canopies open (picture source)

  • The wing root of the MiG-31 has a small strake added while the wing of the MiG-25 is a pure trapeze with a straight leading edge. The picture below shows the MiG-25 in black lines and the MiG-31 overlaid in red.

Three-side view of the MiG-25 and MiG-31

  • $\begingroup$ Stud points for the amazingly detailed answer $\endgroup$
    – David
    Commented Oct 4, 2016 at 5:53
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    $\begingroup$ @David: And I thought I left many details out to make it more concise. $\endgroup$ Commented Oct 4, 2016 at 6:48
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    $\begingroup$ I saw a good documentary about Mig-25 and Mig-31 on Youtube not long ago. Worth seeing, it explains a lot of details, decisions and initial problems they had. $\endgroup$
    – c4n
    Commented Oct 8, 2016 at 18:02

Answering it from another point of view, the MiG-31 had to be the better MiG-25 mixed with the advantages of the Tu-128 As the Successor of the Tu-128 (the Tu-148,T-58M / T-6 and the Yak-33) did not work out, the MiG OKB was the only one left to build a new far range Interceptor With the possibility of using a new engine, the D30F, bigger ranges, slower landing speeds the E-155M emerged

different materials were used, more titan (8%->16%) and light alloys (11%->33%)


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