rodge
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MD 82 Wing Placement

Mon Apr 24, 2006 9:12 pm

Hi all,

Is there a tecnical reason why the sings on the MD 82 are so far back:

Eg:


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To me, they seem too far back.

Why?
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DH106
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RE: MD 82 Wing Placement

Mon Apr 24, 2006 9:42 pm

Simple center of gravity reasons - heavy engines at the back.
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Starlionblue
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RE: MD 82 Wing Placement

Mon Apr 24, 2006 10:21 pm

If you look at the MD-90 you will see that the entire stretch from the MD-81/82/83/88 is forward of the wing, making this effect even more pronounced. This is to compensate for the added weight of the engines.


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SlamClick
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RE: MD 82 Wing Placement

Tue Apr 25, 2006 12:22 am

Quoting DH106 (Reply 1):
heavy engines at the back.

Correct.

Also the T-tail is heavier than a conventional tail because the vertical fin must support the weight and dynamic loads of the horizontal stab. Also the APU and the packs are located back in the tailcone. There is an aft airstair and door in the pressure bulkhead all of which add weight back there.

If you could have an MD-80 fuselage, without the wings, the balance point would be very far back along the tube. In fact, the station where the wings are mounted reflects this.
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Starlionblue
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RE: MD 82 Wing Placement

Tue Apr 25, 2006 12:46 am

The same design decisions are reflected in the placement of the 727 wing:

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As SlamClick says, lots of weight back there:

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[Edited 2006-04-24 17:48:03]
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n685fe
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RE: MD 82 Wing Placement

Tue Apr 25, 2006 11:54 am

Quoting Starlionblue (Reply 4):
The same design decisions are reflected in the placement of the 727 wing:

Incorrect. The 727-200 fuselage plugs were added to body station lines 720 and 950, repeated six times and identified by the letter A through F. Each cover a distance of ten feet. Station 950 begins just aft of the main wheel well area.
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Starlionblue
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RE: MD 82 Wing Placement

Tue Apr 25, 2006 9:12 pm

Quoting N685FE (Reply 5):
Quoting Starlionblue (Reply 4):
The same design decisions are reflected in the placement of the 727 wing:

Incorrect. The 727-200 fuselage plugs were added to body station lines 720 and 950, repeated six times and identified by the letter A through F. Each cover a distance of ten feet. Station 950 begins just aft of the main wheel well area.

I meant that compared with, say, a 737, the wing is further back.
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Mir
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RE: MD 82 Wing Placement

Wed Apr 26, 2006 5:44 am

The MD-11 (and DC-10) wing is pretty far back too. Again, heavy engine at the back that affects the center of gravity.

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N766UA
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RE: MD 82 Wing Placement

Wed Apr 26, 2006 9:40 am

CRJ-900 is the same deal. As is the -700 for that matter.
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n685fe
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RE: MD 82 Wing Placement

Thu Apr 27, 2006 11:07 am

Quoting Starlionblue (Reply 2):
If you look at the MD-90 you will see that the entire stretch from the MD-81/82/83/88 is forward of the wing, making this effect even more pronounced. This is to compensate for the added weight of the engines.



Quoting Starlionblue (Reply 4):
The same design decisions are reflected in the placement of the 727 wing:

Since you only showed -200 in the pics you chose, I thought you suggested that the entire stretch was forward of the wing like you mentioned above.
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Starlionblue
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RE: MD 82 Wing Placement

Thu Apr 27, 2006 9:34 pm

Quoting N685FE (Reply 9):
Since you only showed -200 in the pics you chose, I thought you suggested that the entire stretch was forward of the wing like you mentioned above.

Nah, I just think the -200 looks better  Wink
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jeb94
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RE: MD 82 Wing Placement

Mon May 08, 2006 2:54 pm

The 717 is a DC9-30 fuselage with a 5 foot plug added forward of the wing to compensate for the engines. The equipment in the tail compartment are smaller and lighter and in production versions the ventral stairs were eliminated. The prototype originally did have ventral stairs but they proved to be too heavy.

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