Re: hydraulic problems with DC-10's??

From:         weiss@ada.SEAS.UCLA.EDU (Michael Weiss)
Organization: SEASnet, University of California, Los Angeles
Date:         08 Dec 92 15:51:09 PST
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In article <airliners.1992.92@ohare.Chicago.COM> drinkard@bcstec.ca.boeing.com (Terrell D. Drinkard) writes:
>In article <airliners.1992.85@ohare.Chicago.COM> weiss@turing.SEAS.UCLA.EDU (Michael Weiss) writes:
>>I am referring to the unbalance of WEIGHT, not THRUST.
>It doesn't matter, the loss of weight on that wing was actually a
>short-term plus in that incident (effectively generated a right-hand
>(positive) roll moment to help counter the loss of lift on the left wing).

I'll reply to this below.

>>Which doesn't disprove my theory.  As it is, though, the loss of the slats
>>(which, according to all my aero classes, only lowers the stall speed but does
>>NOT increase the coefficient of lift!) was enough to stall the wing
>It isn't possible to lower the stall
>speed without improving the coefficient of lift (assuming constant weight,
>air density, and wing area).

Actually, assuming constant wing GEOMETRY, which includes, besides area, shape
as well.  Slats change the geometry.  Their benefit is a reduction of the
stall speed, through delay of separation.  I believe the way that it does this
is by directing a stream of air along the upper surface of the wing.

In any case, my point is that there would have been a severe weight unbalance
between the wings, and I have doubts that it could have been countered by the
ailerons.  The whole reason that there was a negative roll moment was that the
left wing STALLED, not that it lost lift directly from the retracting slats.
I'm still not convinced that even WITH the slats extended it could have been
prevented.
-- 
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-  Michael  weiss@seas.ucla.edu   |  School of Engineering & Applied Science  -
-   Weiss   izzydp5@oac.ucla.edu  |   University of California, Los Angeles   -
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