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Su-27 auxillary air intakes


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Hi EagleAviation.

the auxiliary air intakes at the bottom of the engine nacelles should be closed on the ground with engines off.

They are spring-loaded and pop open depending on the air pressure in the intake. Note that even then they rarely open all at once.

Cheers,

Markus

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As Markus says, they are spring-loaded and open on demand from the engine.

I took these photos at Khodynka, Moscow a few years back - I just pushed open the louvres with my hand.....

Intake_07.jpg

Intake_08.jpg

I think that photo you posted showing the mesh FOD guard is probably mine as well............

Ken

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Ken, ref. your 2 pics above. You say you pushed them open by hand, and they stayed that way? Since they are spring loaded why didn't they close before your pics? Always been curious about that.....

It was on the T10-20 out in the open at Khodynka - not rusty enough to be seized up, but enough dirt and lack of lubrication to not snap back into place.

The same should apply to Mig-29 too? The upper aux louvers would be closed if the aircraft is sitting on the ground without the engines running?

Correct - with the engine running on the ground, the front 'door' is closed and air enters via the upper intakes as an anti-FOD measure.

At rest with engine off, the upper intakes are closed (and the front door is usually open - but with a red blanking plate in place).

The new Yak-130 has an interesting anti-FOD system - the same door blanks off the front intake and opens up the upper intake when taxying on the ground....

Front blanked off - air enters via the upper opening....

day_05_44.jpg

It's like a toilet lid - up or down...

day_05_47.jpg

Apparently at the Farnboroigh show, the Yak-130 was taxying out as normal with the FOD door down - and were advised by ATC that they still had their engine blanks in place :woot.gif:

Ken

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At rest with engine off, the upper intakes are closed (and the front door is usually open - but with a red blanking plate in place).

Sorry for the derailment of the thread - but Ken, your sentence above is for the MiG-29, right? It would be correct to have a parked MiG-29 with the upper intake gills shut, and the main intake guard stowed (not covering the intake) so you could see down the intake, right? Assuming one didn't want to put covers over everything, that is.

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As Markus says, they are spring-loaded and open on demand from the engine.

I took these photos at Khodynka, Moscow a few years back - I just pushed open the louvres with my hand.....

Intake_07.jpg

Intake_08.jpg

I think that photo you posted showing the mesh FOD guard is probably mine as well............

Ken

That is excellent! Thanks Flankerman. This is exactly I was looking for.

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Sorry for the derailment of the thread - but Ken, your sentence above is for the MiG-29, right? It would be correct to have a parked MiG-29 with the upper intake gills shut, and the main intake guard stowed (not covering the intake) so you could see down the intake, right? Assuming one didn't want to put covers over everything, that is.

I can't immediately find a photo in that exact configuration - 'cos the groundcrew usually fit the red blanking plates a soon as it shuts down (and put a red cover over the grilles for the crew to step on).

But I'm sure you could find a photo showing the Fulcrum parked, engine off, with anti-FOD doors open and upper grilles closed.

I'll try to find such a config.....

Ken

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oN THE sU-27, The lower louvers only open when the aircraft is in an extreme AOA maneuver ... THe airflow is actually what forces them open.. A the AOA returns back to normal..... the louvers close ..... THese louvers have nothing to do with FOD protection like with the Mig 29..... The Su-27 could not perform pugachevs cobra without these lover louvers of airflow would stall the engine....

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