The MiG-35 has movable panels on the LERX (leading edge root extensions). There are a number of images around the web showing these panels deployed during slow flight and retracted otherwise.

When do they have to use these and what does the use of them change in the flight envelope?

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    $\begingroup$ Here may be a better picture, are you talking about those curved pieces at the root of the wing? $\endgroup$
    – Ron Beyer
    Oct 8, 2019 at 13:58
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    $\begingroup$ slats not flaps (flaps ar all the way from the root towards the tip of the wings). $\endgroup$
    – George Geo
    Oct 8, 2019 at 14:02
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    $\begingroup$ Those are Krueger flaps on the Leading Edge Root Extensions ( LERX ). $\endgroup$ Oct 8, 2019 at 14:23
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    $\begingroup$ @George Geo source for your slat/flap definition please? $\endgroup$
    – Jpe61
    Oct 8, 2019 at 16:16
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    $\begingroup$ @PerlDuck that's one hell of a jam on that lid, if it stays open in flight. $\endgroup$ Oct 9, 2019 at 8:02

1 Answer 1


The aerodynamic devices in question here were already present on MiG-29KUB which is a parent version of MiG-35: Wikipedia: MiG-35

The devices are in fact, as some have suggested, Krueger flaps, as Russian test pilot Pavel Vlasov describes in this article: The MiG-29KUB: in the Russian and Indian skies for 9 years

"It is a modern multirole plane with revolutionary fighting capabilities, with an increased payload and a longer list of weapons," said Pavel Vlasov, Honoured Russian Test Pilot, Hero of the Russian Federation, and General Director of the Gromov Flight Research Institute (and Head of the Flying Service at MiG until 2010). He noted at the same time that the MiG-29KUB featured a range of new solutions, such as Krueger flaps, a new flap design, a modern fly-by wire control system, and significantly improved piloting conditions

In addition to calling them Krueger flaps, this article also gives the devices the acronym LEVCON, leading-edge vortex controllers: SlideShare: Fulcrum Reloaded (see page 4)

The purpose of Krueger flaps is to increase the coefficient of lift of the wing, and to improve slow speed handling: Wikipedia: Krueger flap

After facts some speculation: the reason the Krueger flaps are not deployed in some of the pictures with gear extended is probably bacause they are not used in take off configuration, and the pictures most likely have been taken in t/o situation, not while the aircraft is landing

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    $\begingroup$ Nice work. Interesting that the aircraft has slats and flaps on its wing, and the "Kruegers" on its strake. One thing notably learned on this site is the undesirable characteristics of a sharp leading edge at higher AOA. They may have put a "flap" on there to "soften" the leading edge in situations where more maneuverability is needed. I would look for the computer, or pilot, to close it in situations where less change in AOA is anticipated. $\endgroup$ Oct 10, 2019 at 3:22
  • $\begingroup$ Nice find with that article. $\endgroup$ Oct 10, 2019 at 14:17
  • $\begingroup$ Oh the things one can achieve with google and time to spare :) $\endgroup$
    – Jpe61
    Oct 10, 2019 at 14:32

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