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arrows showing possible asymmetric LEF
Original: russianplanes.net

On this Mig29 in above picture leading edges are at different angles not in line. Same thing happens in flight times when rolling?

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  • $\begingroup$ I think you are thinking of the "all moving" tail, not leading edges. Most modern fighters do this, not just the MiG-29, but in this picture they are both the same angle... $\endgroup$
    – Ron Beyer
    Mar 18 at 11:45
  • $\begingroup$ No, the moving frontal edge of the aircraft (slats) not stabilators /elevators used for pitching up or down. $\endgroup$
    – George Geo
    Mar 18 at 12:11
  • $\begingroup$ At the root of the wings is clear like daylight just where the leading edges extension meet the wings $\endgroup$
    – George Geo
    Mar 18 at 12:38
  • $\begingroup$ The F18 Hornet fly by wire controll this asymmetrical deployment of this part when is in bank and continues to make multiple rolls, but Mig29 is not. $\endgroup$
    – George Geo
    Mar 18 at 12:42
  • $\begingroup$ OK I guess I do see some asymmetry there. On aircraft's right side the sharp "crease" at front of leading edge on fuselage wing root extension, and on actual wing, are aligned, while on the other side they aren't. $\endgroup$ Mar 18 at 12:44

2 Answers 2

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According to Jane's via janes.migavia.com, the leading edge flaps (LEFs) are driven on the MiG-29:

Leading edge flaps have two-positions controlled by dedicated computer and driven as a function of Mach number and angle-of-attack.

enter image description here
Frames from YouTube video HD Cockpit View Flight MiG-29, Poland Air Force at around 2:34 and 2:40.

Video evidence shows symmetric deployment in-flight, even in/into a bank (shown above), unlike the F/A-18. Frame-by-frame the deployment is symmetric but not instantaneously so; it's possible the photo was taken just as they were being deployed for takeoff, which is done independently of the flaps:

From a longer video that includes the taxi to takeoff: while taxiing the LEFs are seen in the retracted position while the flaps are already extended, then the pilot extends and retracts the LEFs (manual test?) before finally extending them again on the runway before applying the takeoff thrust. (This explains the deployed flaps in the photo.)

Note that the MiG-29 first flew in 1977, and fly-by-wire (FBW) was added to the 2005 variant, which used to be known as MiG-33 but is now called MiG-29M. The M being a new fighter, public information is hard to come by regarding its FBW.

enter image description here
wikimedia.org [cropped]

Note that unlike slats, LEFs do not create a slot (shown above on a first-generation MiG-29).

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  • $\begingroup$ So could be named flaps on leading edge $\endgroup$
    – George Geo
    Mar 18 at 19:56
  • $\begingroup$ If they are just leading edges hinged somewhere to they tilt down, they are LE flaps. A slat extends forward and opens up a gap. The ones in the pic in ymb1's answer look like LE flaps, not slats. Looks like I might have been screwed by wikipedia... again... lol. $\endgroup$
    – John K
    Mar 18 at 20:12
  • $\begingroup$ @ymb1 the one in the OP pic has flaps down and elevators fully up. Perhaps it's going through the flight control systems BITE and the LE flaps move independently during that. $\endgroup$
    – John K
    Mar 18 at 20:20
  • $\begingroup$ @JohnK: My first thought was something like the F/A-18, but I couldn't find any corroborating info. $\endgroup$
    – user14897
    Mar 18 at 20:55
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Guess the problem is that the pressure in actuators from left side is different from the right side in the stand-by and this creates the difference between the two sides when it is parked on the ground, but in the air that it is not possible due to the functionality of the actuators (high performance need high level of pressure ) .

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    $\begingroup$ "in the air that it is not possible" is explicitly contradicted and explained why and how it can happen in John K's answer (the one you accepted). Care to explain why you think it can't? $\endgroup$
    – FreeMan
    Mar 18 at 16:14
  • $\begingroup$ @FreeMan Because I believe that there is a system called" asymmetry brake" that does not permit any asymmetrical deflection. Early on in Bf109 time frame if that happens at slower speed in banked turn the aircraft spin. Nowadays I getting a sense that is not a problem anymore $\endgroup$
    – George Geo
    Mar 18 at 16:31
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    $\begingroup$ No the system in the 109 was not a "driven" system. Its slats were free floating and could extend asymmetrically during maneuvering. You are thinking of airliners most of which use power driven slats that only extend with flaps. $\endgroup$
    – John K
    Mar 18 at 16:55
  • $\begingroup$ Now I read about the take off/ landing schedule of the slats and flaps 20 /25 degrees for MiG 29. If (the slats here in discussion ) are free then how in the world can be released only at this anglei if not driven? $\endgroup$
    – George Geo
    Mar 18 at 18:13

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