Trivia #1

[Blinder]

Look closer.

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I love that Polish paint scheme... Especially with the WWII heroes they honor on the tail.

In T/O and landing config the engines draw air from the gills on the upper surface of the LERX. Internal doors close the main intakes. The Su-25 doesn't need any since it sits so high off the ground in a nose-up attitude.

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I want a Frogfoot!  What are they selling for these days?

[GScholz]

I've heard about a privately owned SU-25, but I've never seen it, and I have no idea what something like that would cost. Lots of decadent imperialist capitalist money for sure! 

[Sombra]

Look closer.

(Image removed from quote.)

I love that Polish paint scheme... Especially with the WWII heroes they honor on the tail.

In T/O and landing config the engines draw air from the gills on the upper surface of the LERX. Internal doors close the main intakes. The Su-25 doesn't need any since it sits so high off the ground in a nose-up attitude.

What your picture shows is the original solution for MiG 29, but as already stated, they changed it in later models to retractable grids in order to use the space inside the LERX for more fuel:

http://forum.keypublishing.com/showthread.php?53622-Su-27-3x-vs-Mig-29-Take-off-amp-landing-from-Unpaved-Rough-field&s=2e717145d60bff855c429b9305fa5f9c&p=847660#post847660

Similar to Su-27's:

http://www.arcforums.com/forums/air/index.php?showtopic=199152&view=findpost&p=1877412

[Widewing]

Until you've done a FOD walk-down on GTMO's ramp, you haven't done one yet. We'd collect at least a dozen land crabs every morning... The occasional Iguana too....

[GScholz]

Those were developed for the naval version of the MiG-29 the K-model. They only needed to stop it from inhaling deck crewmen and their back-pocket spanners!  Unlike the MiG-29 the Su-27 is not a "front line fighter" and wasn't expected to operate from rough unprepared runways. Its primary mission was/is to defend the Soviet Union/Russia from strategic bombers. However, still the Su-27 has a highly effective protection against ingesting foreign objects.



Anything that gets through that screen won't be big enough to cause any problems.




Except for the original MiG-29M all the modernized versions also have the gills, like this MiG-29SMT:

[DaveBB]

This info came from a Russian pilot.  He said the FOD screens on the Mig-29 did not work as intended.  Since they retract, anything on the screens will just get sucked into the engine when retracting.

[GScholz]

What MiG did he fly? The 29K?   On the land based 29s there are no screens. There are doors.





I can't see how any FOD would get stuck on those doors unless you somehow spray them with mud. There can't be enough airflow to suck anything up from the ground.


The screens on the Su-27, in my previous post, retract downward trapping the FOD underneath them.

[Sombra]

Except for the original MiG-29M all the modernized versions also have the gills, like this MiG-29SMT:

If I'm not mistaken, the MiG-29SMT is an upgrade designed around the early airframe, so it can be retrofited to existing MiG-29s. It was an attempt to give old 29s capabilities similar to the MiG-29M. From what I have read, there is a further development around it, the SMT-2, that dispenses with the louvers.

The MiG-29M has been the basis for the "latest and greatest" development, the MiG-35 (so devoid of louvers too). You get a glimpse of the grids of the engines in this video at 0:20. It's the best that I could find!

http://youtu.be/zDfmfp4dUrc?t=20s

[GScholz]

Yes, all the upgrades for the MiG-29 are just that... Upgrades. I've never heard of the SMT-2, but the MiG-35 seems to be an upgraded 29M. Mikoyan must need more export money to develop the LMFS!

[DaveBB]

On top of all this, it was discovered that the unique FOD doors on the MiG-29's inlets were not stopping material from getting into the engine ducts. Since the doors retracted "up" into the inlet, debris that was kicked up by the nose wheel lodged on or at the bottom of the door seal and then was ingested into the engine when the door opened during the nose gear lifted off the ground during takeoff.

This problem was known from the earliest days. After the first four MiG-29 prototypes were evaluated, the nose gear was moved further back, but nose wheel "mud-flaps" or guards were still required to protect the engine from flying debris. It took until 1988 before all delivered aircraft were so equipped, therefore the initial batch of InAF aircraft had to be locally retro-fitted with mud guards and that activity was not completed until June 1992. All costs were supposed to be re-imbursed by the contractor but Mikoyan reneged and left the InAF with $300,000 in liabilities. In subsequent MiG-29K/M models the FOD doors were replaced by screens that closed "down", forcing any debris out of the louvers repositioned to the lower side of the inlet duct..

http://www.sci.fi/~fta/MiG-29-2b.htm

[XxDaSTaRxx]

Enjoy your cabbage soup and Vodka for dinner comrades

[GScholz]

http://www.sci.fi/~fta/MiG-29-2b.htm

Like I said: "I can't see how any FOD would get stuck on those doors unless you somehow spray them with mud."

From your link:

"On top of all this, it was discovered that the unique FOD doors on the MiG-29's inlets were not stopping material from getting into the engine ducts. Since the doors retracted "up" into the inlet, debris that was kicked up by the nose wheel lodged on or at the bottom of the door seal and then was ingested into the engine when the door opened during the nose gear lifted off the ground during takeoff.

This problem was known from the earliest days. After the first four MiG-29 prototypes were evaluated, the nose gear was moved further back, but nose wheel "mud-flaps" or guards were still required to protect the engine from flying debris. It took until 1988 before all delivered aircraft were so equipped, therefore the initial batch of InAF aircraft had to be locally retro-fitted with mud guards and that activity was not completed until June 1992."

[TheCrazyOrange]

It seems to me a similar solution could quite quickly be retrofitted to any engine. @

[shermanjr]

motivated police call