Re: New MD-80, MD-88 tailcones?

From: (Hayes N. Press)
Organization: Lockheed Engineering and Sciences Company
Date:         25 Aug 93 02:53:31 PDT
References:   1
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 In article  <airliners.1993.560@ohare.Chicago.COM> (Philip Papadopoulos) writes:

>I noticed on a recent trip that some MD-80's (MD-88's, too) have
>"flattened" tailcones (versus conical ones). Could someone give
>me some history on this development. 

The "flattened" tailcones were designed as a replacement/design change
on all MD-80 series aircraft since at least 1986.  It was done to decrease
fuel comsumption by both decreasing drag at the tail and by the change
to the use of more composite material.  As far as I know, no airline is 
actively retrofiting their tailcones but they may replace them with the 
newer designed one when and if a replacement is needed.

>BTW, the flattened and elongated tailcone is very apparent on
>American jets, less so on Delta Jets. I saw about 8 Northwest
>MD-8x's and none had the flattened cone. All the American Jets
>I saw did have the new cone (about 15 examples) and most
>(but not all) of the Delta jets had flattened tailcones.

The main reason for your observation probably has a lot to do with fleet
age and mix.  American Airlines has the largest fleet of MD-80's with 
over 200, and at one time this was the record for the industry of one 
airline have such a large fleet of one type aircraft.  The Northwest  aircraft
you observed were probably all DC-9 series aircraft and these older models
gennerally have not been changed.  To the best of my knowledge NW has no
MD-80's in its fleet.  And Delta falls right in the middle.

Speaking only for myself and all standard disclaimers apply.