Re: 767 Service Ceiling

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
Date:         05 Aug 94 03:35:29 
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Terry Drinkard wrote:
>There are obvious economic tradeoffs that determine what maximum
>certified altitude to design for - the higher weight of the stronger
>skins ... The short hop guys (Southwest comes to mind) don't give a
>rip about high altitude capability ...

Interestingly, a friend once mentioned to me that the 737 does *not*
use much of the 727 fuselage tooling because it's skin is *thicker*.
It doesn't need the higher altitude capability, but it's expected to
undergo a greater number of pressurization cycles (lots and lots of
short flights instead of fewer, longer flights) and therefore needs
a stronger fuselage.

I've never verified this factlet, but it makes sense to me.

>no one ever buys us a beer.  :-)

Remind me to buy you a beer next time I'm in Seattle.  :-)

>The lowest climb parameter I've seen is 300 fpm, and that is well
>above even the 500 fpm line ... a better indication of altitude
>capability is certified maximum altitude.

Ok, but what can a 767 really do?  Or if you prefer, what was the 300
fpm number for (type and altitude)?  I realize it's not particularly
useful, except perhaps in an application like the Vomit Comet.  (As I
recall, they start their dive in that from well above the normal
ceiling for a 707.)  Is the number in the same league as a B-47/B-52?
Seems to me one of those has seen at least 55,000 ft, maybe over
60,000.

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