AS907
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Posts: 49
Joined: Sat Sep 03, 2005 7:29 am

MD-80 Engines

Sat Feb 25, 2006 5:56 am

Hi everyone. This is the first topic I have started here on A.net! While working at ANC, I would get to see AS MD-80s close up and noticed something different with the engines. It looks as though they are parallel to the ground while the fuselage has a slight downslope to it. At the time, it looked like there was a huge difference in the angle between the two, but I can't find any pictures in the database that show it very well. I was just curious... was I imagining this huge difference in the angle? And if not, what are the benefits of having the engine not parallel with the fuselage? Thank you.



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aeroweanie
Posts: 1577
Joined: Fri Dec 03, 2004 9:33 pm

RE: MD-80 Engines

Sat Feb 25, 2006 7:03 am

Yes, the engines on the MD80 are mounted with about 2.8 degrees of pitch. This is to align the engine with the downwash behind the wing.
 
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Starlionblue
Posts: 17097
Joined: Fri Feb 27, 2004 9:54 pm

RE: MD-80 Engines

Sat Feb 25, 2006 7:51 am

They are also toed out, that is the intakes point outwards in the vertical plane. Wing mounted engines are toed in instead. This is all to align with airflow.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
speedracer1407
Posts: 330
Joined: Fri Dec 24, 2004 4:19 pm

RE: MD-80 Engines

Sat Feb 25, 2006 11:52 am

I remember a previous thread that discussed the same thing. I can't remember for sure, I think some posters opined that, while the engines were mounted with a bit of pitch, the intakes, and thus the whole nacell, were mounted with even more pitch, thus giving the impression of a dramatic difference between the angle of the fuse and the angle of the engines.
Dassault Mercure: the plane that has Boeing and Airbus shaking in their boots.
 
MX757
Posts: 495
Joined: Wed Aug 17, 2005 5:38 pm

RE: MD-80 Engines

Sat Feb 25, 2006 4:39 pm

Quoting AeroWeanie (Reply 1):
Yes, the engines on the MD80 are mounted with about 2.8 degrees of pitch. This is to align the engine with the downwash behind the wing.



Quoting Starlionblue (Reply 2):
They are also toed out, that is the intakes point outwards in the vertical plane. Wing mounted engines are toed in instead. This is all to align with airflow.

It's funny, the little things like that. I worked DC9/MD-80's exclusively for 3 years back in the mid 90's and I never paid any attention to engine pitch and toe out angles. I guess I was too busy fixing the damn things. Interesting little tidbit though. Thanks for the info.  Smile
Is it broke...? Yeah I'll fix it.
 
nonfirm
Posts: 426
Joined: Mon Sep 12, 2005 3:04 pm

RE: MD-80 Engines

Sat Feb 25, 2006 5:45 pm

Quoting MX757 (Reply 4):
It's funny, the little things like that. I worked DC9/MD-80's exclusively for 3 years back in the mid 90's and I never paid any attention to engine pitch and toe out angles. I guess I was too busy fixing the damn things. Interesting little tidbit though. Thanks for the info

I have been working on them for 14 years and went and looked at them again tonight i never noticed either that is because as an MD mech you only get to look at the side of the Eng.  scratchchin 
 
Airgypsy
Posts: 130
Joined: Tue Nov 23, 1999 11:02 am

RE: MD-80 Engines

Sun Feb 26, 2006 1:16 pm

The MD-80 grew from the DC-9 in several ways. It got longer, so they put a longer landing gear on the MD-80 to keep the tail from dragging on takeoff (kept the same nose gear). The wing is bigger so, they added a Zero (0) slat instead of renumbering the others.
I was with PSA and worked both MD-80s and DC-9 30s. Hated the dirty thirties because they were real head bangers and tail draggers. The "dragster" rake of an MD-80 does look cool.
Airgypsy

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