Re: Aircraft not toppling onto rear (VC10)

From:         drinkard@bcstec.ca.boeing.com (Terrell D. Drinkard)
Organization: Boeing Commercial Airplane Group
Date:         11 Feb 94 03:55:05 PST
References:   1 2 3 4
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In article <airliners.1994.922@orchard.chicago.com>,
Gregory R. TRAVIS <greg@bronze.ucs.indiana.edu> wrote:
>In <airliners.1994.918@orchard.Chicago.COM> julian@gatwick.sgp.slb.com writes:
>
>>c) Overly strong fuelage and wing construction (Comet legacy) so lots of
>>   weight ahead of the main wheels.
>
>Comet legacy?  I distinctly remember several Comets coming apart in
>mid-air.  Or are you saying that the redesigned Comets were over-engineered
>to avoid embarassment?

I rather doubt that the Comets are over-engineered for their time, the
1950s.  Granted, they missed the stress buildup around the window holes and
forgot to put in a flange to give themselves more area (P/A you know), but
the big issue in that time, IMHO, was fatigue life vs weight (come to think
of it, that is still a big issue driving gobs of materials work).  Look at
the DC-8 and the 707, and the Lockheed Electra, all designed in that same
era with essentially the same alloys.  Tremendously long lives.

>>d) 90% + of payload located ahead of main wheels (I think that's about right).
>
>Is this true?  How the heck do you rotate, or flare, a VC10?  I find
>this hard to believe, considering they have four aft-mounted engines!

Um, I don't think so either.  Typically, you'll find the main gear a few
tens of inches behind the aft CG limit.  Therefore, you shouldn't expect
more than 55% of the airplane's weight in front of the main gear.

But, after another millisecond's thought, I note that julian wrote 90% of
the PAYLOAD is forward of the gear.  Not that I agree with that either,
even Douglas puts less than 70% in front of the mains.  That number is
eyeballed, by the way, and is strictly my uninformed opinion, your mileage
may vary.  Karl probably has better numbers than I do.

Terry

-- 
Terry
drinkard@bcstec.ca.boeing.com
"Anyone who thinks they can hold the company responsible for what I say has
more lawyers than sense."