Re: 747 with engines on the wings?

Date:         19 Feb 98 01:33:51 
From:         westin*nospam@graphics.cornell.edu (Stephen H. Westin)
Organization: Program of Computer Graphics -- Cornell University
References:   1
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RLION@worldonline.nl (Lion's Pers Agentschap) writes:
>  What is the reason that airliners have engines under the wing instead
> of on it?
>
>  Possibly it will take a little bit more aluminium to construct
> airliners this way, but with overwing engines the wing can deflect a
> big portion of the noise for people living around airports. (This can
> be reached even without improving the engines themselves!)

Please cite the tests that have shown this.

<snip>

> (If you want to see how a Boeing 747-400EOW (engine on wing) looks
> like, visit:
> http://home.worldonline.nl/~rlion/lapr011e.htm

Well, I think the airflow over the wings might be a bit problematic
with the configuration shown. Not to mention the problems of blasting
the aluminum skin with hot exhaust, a situation that required
modifications to early DeHaviland Comets.

I think the traditional underwing mounting was chosen to minimize
airflow interference with the wing. Notice that the VFW-614 mounted
its engines well above the wing. See

 <http://www.bs.dlr.de/wt/fb/bs/ATTAS.HTM>

for a photo of one still in service as a testbed for DLR. This one has
been modified with a fly-by-wire system to simulate the handling
characteristics of various aircraft.

Low mounted engines will also tend to increase the angle of attack by
twisting the wing, which is probably not a bad thing at takeoff
time. Didn't the VFW-614 require special stiffening to counteract
unfavorable wing twist?

Finally, engine inspection and maintenance would be more complicated
with over-wing engines.

<snip>

>   Lion Air - The Royal Dutch Alternative
"Lion Air is a virtual airline. We cannot accept your bookings!"

I think we have progressed beyond vaporware to vapor airlines...

--
-Stephen H. Westin
Any information or opinions in this message are mine: they do not
represent the position of Cornell University or any of its sponsors.