Re: hydraulic problems with DC-10s??

From:         barr@ash.mmm.ucar.EDU (Keith Barr)
Date:         10 Dec 92 00:52:10 PST
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  or MIME structure (Gregory R. Travis) writes:
> BTW, just to be pedantic:  The wings do not each contribute exactly
> 50% of the total lift.  Remember that that fuselage itself contributes
> a SUBSTANTIAL amount of lift at cruise as do the horizontal stabilizer
> surfaces (in certain flight regimes!).

What flight regimes might those be?  Unstable flight, as in the F-16?

Actually, in most aircraft the horizontal stabilizer is downlifting, so
the wings have to create more lift, and the body contributes to the
pitching moment, but contributes very little lift (unless we are talking
about the B-2).

For the horizontal stabilizer to lift up, the CG would have to behind the
Center of lift, which is not usually allowed.  I would bet a dollar that
the DC-10 has a down lifting tail, although I don't know for sure.

If you want references for either of these points, I recommend that you
look at Etkin's book on stability (an engineering text I used in my
aircraft design class that would explain in painful detail why you need
the CG in front of the Center of Lift), and you might check out K.D.
Wood's text on aircraft design for discussions about pitching moment and
lift created by the fuselage.

(is it just me, or is this thread becoming less and less appropriate for
this newsgroup?)
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