Re: 737-plus?

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works
Date:         08 Jul 93 14:18:36 PDT
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>>Meanwhile, the 747-400 is receiving modifications including a
>>redesigned composite dorsal fin fairing and fuel distribution system
>>which will allow a 2,000 lb increas in MTOW.  The changes will be

>Can this be for real ?

>It allows another 10 or so pax, or another ton of fuel.

Or another ton of cargo.  I recall hearing at one point that United
was perfectly happy flying 747SPs between San Francisco and Tokyo with
half of the seats empty -- they could devote that much more capacity
to cargo, and were taking their empty seats straight to the bank.
Think of that extra ton as 2,000 overnight parcels at an average of a
pound apiece, at a fare of $10 each.  (Maybe more for international --
I'm just picking ballpark numbers here.)  $20k per flight can add up
quick.

Beyond that, the redesigned fuel distribution system may be the more
important piece here.  I don't know the details, but keep in mind two
points.  First, the 747-400 has fuel tanks in the tailplane (an option,
but likely to be present on any high-weight aircraft).  Second, any
jetliner is somewhat noseheavy and thus requires the tailplane to push
downward in flight, which in turn creates some drag.  I believe planes
with tail tanks already have some ability to manage trim by moving
fuel to the tail, thereby requiring less downforce from the tailplane
and thus less drag.  However, if the new system on the 747-400 does a
better job of this it could result in a significantly reduced fuel
burn, which would likely be worth quite a bit.

Anybody from Boeing care to provide some details?

--
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