Re: B737-400 range

Date:         08 Jan 2000 13:39:02 
From:         Petrus Lundqvist <peppe@peppe.net>
Organization: peppe.net
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> Generally the range is quoted at optimum conditions in still air, and
> often involves serious payload penalties. How serious a payload penalty
> you are prepared to pay in no small part determines the range.

Right.. But when they say 2050 nm, do they mean "the plane can fly from
routes from an airport 2050 nm away from another and still have 45 minutes
worth of reserves" or do they mean "the plane can take off, fly 2050 nm
on absolutely optimal speeds and altitudes, run out of fuel at 36000 feet
and then glide down and BARELY make the target airport, which is 2050 nm
away from the takeoff".

Also, the fact that the Boeing homepage for the 737-400 lists two different
versions but only one range which seems strange. It says:

"The basic airplane gross weight is 138,500 pounds (62,820 kg), with an
optional high-gross-weight version of 150,000 pounds (68,040 kg). Fuel
capacity is 5,311 gallons (20,105 L), expanding to 6,295 gallons (23,825 L)
with two optional tanks."

How can both have a range of 2050 nm "with 148 passengers" when one version
has 20% gallons more fuel? Seems weird.

> Boeing quotes the 747-400 as having a 8400nm range. at economy cruise
> that is about 17 hours. If you work backward from the fuel required,
> such an activity will take 135,000 pounds or so out of the lift
> capacity. That means you would probably have a hard time doing it in an
> empty airplane if it had a passenger interior fitted!.

Hehehe, yeah.. Well, it's not surprising that they knock the results in
the direction which sells more planes, of course. But it seems a bit weird
to list ranges which are not even close to realistic in a real environment.

Cheers,

Peppe