Re: MD-17 vs. MD-11F/DC-10F

Date:         01 Jan 97 20:59:21 
From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
References:   1 2 3 4 5 6 7 8 9 10
Followups:    1 2 3 4 5 6 7 8 9
Next article
View raw article
  or MIME structure

>> For many interesting cargo routes, however, it's range isn't enough more
>> to eliminate fuel stops.  I think SFO-NRT was an example.  Both planes
>> need a fuel stop, usually at ANC.  The fact that the -400F could fly a
>> greater percentage of the flight before stopping is neither interesting
>> nor useful.

>Are you considering only transpac routes?  There are many others in the
>world where the extra range of the 400F pays off very well.

I said many routes, as that's what was said in the article I referred
to (probably in AW&ST, though I still haven't found it).

AW&ST lists cargo capacity of the 747-200F as 245,300 lbs, with the
-400F only a little (9.4%) more at 268,300 lbs.  Their range numbers
do not appear to be credible (4,080 miles for the -200F, 3,165 miles
for the -400F) but that may be comparing max range for the -200F to
full load range for the -400F.

Here's what Boeing has to say about the 747-400F on www.boeing.com:

   Weights and Ranges (carrying 124 tons of payload)

   Max TO weight    Range
   800,000 lbs      3,200 nm
   833,000 lbs      3,760 nm
   850,000 lbs      4,050 nm
   875,000 lbs      4,450 nm

Compared to the -200F, Boeing says

   The -400 Freighter can carry 124 tons (113,000 kg) of cargo more than
   4,400 nautical miles. An additional 26 tons of payload or 1,200 nautical
   mile range is possible compared to Boeing's 747-200 Freighter.

If I'm reading that correctly, it sounds like a -200F can carry 98
tons 4,450 nm, or 124 tons 3,250 nm.

SFO-NRT is 4,452 nm, beyond the range of either model.  Only by a very
small margin for the highest MGTOW -400F, but ditching off the Golden
Gate or in Tokyo Bay doesn't win any points.  :-)  Since both must make
a fuel stop, the -400F's range advantage is of no consequence.  It can
carry a higher payload, but the segment distance is such that the -200F
payload is not substantially reduced by the need for a heavy fuel load.

Across the Atlantic, JFK-AMS is 3,166 nm.  That's within the max load
range of the -200F, so again, the -400F's additional range doesn't buy
anything.

In each example, the -400F's advantages are a payload increase of less
than 10%, fuel burn reduction of 10% to 16% (according to Boeing), and
elimination of the flight engineer.  Given the huge disparity in
capital costs of a new 747-400F versus a 747-200, possibly converted
from a full depreciated 747-200B, these advantages are not terribly
compelling.

There was one group of routes where the article claimed the -400F does
have a measureable advantage.  I don't recall where that was, but a
good guess would be routes like SIN-LAX.  At 7,620 nm non-stop, a
-200F needs two stops.  (It could do the job with one close to the
midpoint, but there aren't any conveniently located airports and that
would require a substantial payload penalty.)  In contrast, a high
MGTOW -400F can in theory make the trip with only one stop without a
dramatic payload penalty.  (I'm not sure what would be a reasonable
place to stop, though.)

--
Karl Swartz	|Home	kls@chicago.com
		|Work	kls@netapp.com
		|WWW	http://www.chicago.com/~kls/
Moderator of sci.aeronautics.airliners -- Unix/network work pays the bills