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Fly2HMO
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MD90 Engine Pylons Control Pitch Too?

Thu Jul 01, 2004 3:29 am

I found this picture that mentioned this in the remark:


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Photo © Brett B. Despain



Which is the control surface? Any other type of aircraft with this?

Cheers  Smile/happy/getting dizzy
 
LMP737
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RE: MD90 Engine Pylons Control Pitch Too?

Thu Jul 01, 2004 5:26 am

The control surface on the MD-90 pylon is meant as a means of stall recovery. In other words they will help push the nose over in the event of a stall.
Never take financial advice from co-workers.
 
aloges
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RE: MD90 Engine Pylons Control Pitch Too?

Thu Jul 01, 2004 6:04 am

Is that feature particularly important because T-tail aircraft are more likely to suffer deep stalls?
Don't cry because it's over, smile because it happened.
 
LMP737
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RE: MD90 Engine Pylons Control Pitch Too?

Thu Jul 01, 2004 7:12 am

Aloges:

You're right on the money. The MD-80 has two hydraulic actuators for the elevator that push the nose over if there is more than ten degrees nose down command.
Never take financial advice from co-workers.
 
MD-90
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RE: MD90 Engine Pylons Control Pitch Too?

Fri Jul 02, 2004 8:12 pm

You know, I never knew that. I just assumed the pylons were pylons.
 
MD-90
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RE: MD90 Engine Pylons Control Pitch Too?

Sat Jul 03, 2004 2:18 pm

Ah, perhaps I see it. The pylons are shaped in such a way as to generate some lift, but they do not have control surfaces on them.


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Photo © Chris Benesh/back2planes

 
Mr Spaceman
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RE: MD90 Engine Pylons Control Pitch Too?

Sat Jul 03, 2004 3:06 pm

Hi guys.

>> MD-90 .......

"The pylons are shaped in such a way as to generate some lift, but they do not have control surfaces on them."

If you look very closely at the first photo you can see what appears to be a hinge line for a very small control surface on the engine pylon's trailing edges as mentioned by the photographer.

They look like small trim tabs with a short chord line of about 8 inches. Can you see them? I believe I can. Big grin



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AAR90
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RE: MD90 Engine Pylons Control Pitch Too?

Sat Jul 03, 2004 3:21 pm

Ah, perhaps I see it. The pylons are shaped in such a way as to generate some lift, but they do not have control surfaces on them.

If you see them or not, they are there. At least they were there and active on all the MD90 flights I flew.  Big grin
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
FDXmech
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RE: MD90 Engine Pylons Control Pitch Too?

Mon Jul 05, 2004 1:49 am

I'm baffled. What movable control surface on the pylons? I've worked the MD80 many years and have crawled on many pylons. Again what movable control surface?

Ahhh...I get it.

[Edited 2004-07-04 18:56:52]
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miamiair
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RE: MD90 Engine Pylons Control Pitch Too?

Thu Jul 22, 2004 9:29 pm

There are NOT any movable surfaces on the pylons at all. What you see is a wedge shaped closure. This is riveted to the span-wise closure rib. They are fixed, and do not move.
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atlamt
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RE: MD90 Engine Pylons Control Pitch Too?

Thu Jul 22, 2004 9:36 pm

MD-90's DO have a control surface on the pylons. As said before it is a stall recovery system activated by pushing the yoke full forward. The pylon "flaps" only deflect down.

Here is the best pic I could find.

Fwd to MEL and Placard
 
LMP737
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RE: MD90 Engine Pylons Control Pitch Too?

Fri Jul 23, 2004 12:34 am

Atlamt:

Good picture of the stall flaps on the pylon. Quick question for you, how's the reliability of the MD-90 in Delta's fleet? And when is Delta finally going to retire the MD-90?

Miamiair:

As Atlamt has pointed out the surfaces on the MD-90 pylon do move in the event of a stall.
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POSITIVE RATE
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MD-90

Fri Jul 23, 2004 1:10 am

"Good picture of the stall flaps on the pylon. Quick question for you, how's the reliability of the MD-90 in Delta's fleet? And when is Delta finally going to retire the MD-90?"

Why would Delta want to "retire" the MD-90. It's hardly an old airplane- an infant in fact compared to the 737-200/300. Isn't it supposed to be a really economical plane? It's just a pity there aren't more of them in service.

 
KDTWflyer
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RE: MD90 Engine Pylons Control Pitch Too?

Fri Jul 23, 2004 1:55 am

Just a last question, what is that opening in the pylon in the last photo for? And also, what is that emergency exit for is that for a galley or something?
 
LMP737
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RE: MD90 Engine Pylons Control Pitch Too?

Fri Jul 23, 2004 1:57 am

Positiverate:

Delta is in the process, like many other large airlines, of reducing the number of fleet types. Since there are only fifteen MD-90's in Delta's fleet it makes economic sense to retire the aircraft. This will save money since you are no longer having to support the type. In addition the MD-90 is not the most reliable aircraft when compared to say the 737-800. It has a rather quirky electrical system that a tendency to give you problems at the gate.
Never take financial advice from co-workers.
 
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Starlionblue
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RE: MD90 Engine Pylons Control Pitch Too?

Fri Jul 23, 2004 2:39 am

KDTWFlyer.

Don't know what the hole is for. Pressure relief from the engine or something?

The emergency exit seems to be a handle/hatch to open the rear emergency exit. The one which blows off the tailcone.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
MD-90
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RE: MD90 Engine Pylons Control Pitch Too?

Sat Jul 24, 2004 12:39 pm

Indeed. Otherwise that's going to be a kids-only emergency exit. It's quite small. Big grin


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