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MiG-29 Intake doors


Jabba

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I am building a couple of MiG-29s and although I think that I am correct I would just like the position of the intake doors when no power at all to be confirmed.

I think that the main intake door is raised, and that the aux doors on the fuselage are shut. Am I correct in this thinking, as most of the pictures that I have of this aircraft on the ground either have covers applied or a pilot in the cockpit and power on.

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I have a book on the MiG-29 which came with a fight sim of the same name some time back in 1991. it appears to be a reprint of an original Osprey book printed in '89 and covers the appearance of the MiG at Farnborough. There are many useful pics in the walkaround, and several cover the plane on the ground in an un-powered state. Every photo I have shows that the upper deck auxiliary doors are closed, and rather surprisingly, the intake doors are retracted. This would suggest that they only drop into position during engine start up, so may be electric rather than hydraulic as I would expect a hydraulic actuator to drop under the weight of the door. Hope this helps. I have no scanner, but if you want I might try to take a photo of a page or two.

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I thought I had the exact answer posted by a Russian guy on another forum, but IIRC...............

At rest, the main intake door is retracted (Open) and upper spring-loaded shutters are closed.

Both would normally have red-painted covers in place - that on the shutters being made to fit the LERX contours with a flat work platform on top.

At engine start (with red covers removed), the main intake door closes (to prevent FOD) - and the engine breathes through the upper shutters - which open on demand from the engine.

This applies all the way to takeoff, when the nosewheel lifts, the main doors retract (Open).

On landing, I think its a weight-on-nosewheel switch that closes the main door.

A model of a MiG-29 at rest with the upper shutters open is a No-No !!!!

Latest versions of the MiG-29 use the Flanker system of a Mesh FOD guard, rather than a solid door.

Ken

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I thought I had the exact answer posted by a Russian guy on another forum, but IIRC...............

At rest, the main intake door is retracted (Open) and upper spring-loaded shutters are closed.

Both would normally have red-painted covers in place - that on the shutters being made to fit the LERX contours with a flat work platform on top.

At engine start (with red covers removed), the main intake door closes (to prevent FOD) - and the engine breathes through the upper shutters - which open on demand from the engine.

This applies all the way to takeoff, when the nosewheel lifts, the main doors retract (Open).

On landing, I think its a weight-on-nosewheel switch that closes the main door.

A model of a MiG-29 at rest with the upper shutters open is a No-No !!!!

Latest versions of the MiG-29 use the Flanker system of a Mesh FOD guard, rather than a solid door.

Ken

Photographic evidence of early 29s show the nose wheel off the floor and the ramp intake covers in the down position, suggesting that the switch governing the doors is on the main wheels, not the nose wheel. Having said that, the nosewheel on the early MiGs was a bit further forward, so could have produced more in the way of FOD.

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Here's the post I was talking about - on another forum, posted by someone called 'grizzly'.......

The FOD protection doors close automatically during engine starting when hydraulic pressure reaches nominal and open when the aircraft accelerates to 200km/h IAS during take-off.

They close again when the airspeed drops below 200km/h, reopening after engine shutdown. Source: Mikoyan MiG-29 by Yefim Gordon.

After touching down, during the landing roll at V < 200km/h, the air intake axial inlet is closed by the ramp front panel doors. Source: MiG-29 Flight Manual by Alan Wise.

Ken

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According to everything I've read, the squat switch for the FOD covers is on the main gear struts.

That's what I used to think..... but it is contradicted by photos of MiG-29's landing - in one pic the aircraft is rolling on its mainwheels with the main doors open - in another the doors are closed.

Heres' a sequence of a MiG-29 landing wot I took ........

mig-29_doors_001.jpg

mig-29_doors_002.jpg

mig-29_doors_003.jpg

The doors may be activated by a weight-on-wheels switch on the mainwheels - but they are (apparently) operated when the forward velocity reaches less than 200km/h as my poster says....

After touching down, during the landing roll at V < 200km/h, the air intake axial inlet is closed by the ramp front panel doors. Source: MiG-29 Flight Manual by Alan Wise.

Ken

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