Re: 747 hump

Date:         10 Sep 97 19:38:45 
From:         David Lednicer <>
Organization: Analytical Methods, Inc.
References:   1
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Marc Schaeffer wrote:
> I wonder to what extend the hump of the 747 contributes to the total
> fuel consumption at cruise speed and cruise altitude. Can the
> aerodynamical disadvantages of the 747-hump be evaluated by some > formula ?

	Actually, the hump slightly improves the drag of the 747.  If the hump
wasn't there, the cross-sectional area distribution would have a chunk
missing and the wave drag would be higher.  I have data showing that the
extended hump on the 747-300 and -400 improves the area distribution
slightly, further reducing wave drag.

David Lednicer             | "Applied Computational Fluid Dynamics"
Analytical Methods, Inc.   |   email:
2133 152nd Ave NE          |   tel:     (206) 643-9090
Redmond, WA  98052  USA    |   fax:     (206) 746-1299