Re: Boeing 747 variants

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
Date:         16 Sep 94 04:30:20 
References:   1
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>What exactly are the differences between a 747-100 and a 747-200?
>And, between a 747-300 and 747-400?

The 747-200B is an improved version of the original 747, the -100,
with higher gross weight (up to 833,000 lbs MGTOW vs. 750,000 for the
-100) and more powerful engines, which permit greater range and/or
greater payload.  QANTAS, I believe, instigated the -200B because the
-100 could not meet their range requirements.

There's also a -100B, which seems to be a heavy -100.  I'm not quite
sure why it exists as it came along years after the -200B.

There is no -200, however.  I'm not sure what happened to it, but all
passenger -200s are -200B models.  There are also -200C (combi) and
-200F (freighter) variations.

Contrary to popular belief, having only three windows in the upper
deck does not indicate a -100.  Most, but not all, -100s were built
as "three holers," but some -200Bs were built that way as well.  In
addition, Boeing offered a conversion kit, which rearranged some of
the air conditioning equipment and extends the upper cabin from 19
feet to 25 feet, in addition to adding more windows.

One you didn't mention is the 747SP, which was designed for very long
range.  90% of the SP is the same as the -100/-200 series, but the
remaining 10% is quite stunningly different.  The fuselage is 47 feet
shorter, while the tail height was increased by 5 feet and the tail
span was increased 10 feet.  Simple flaps replaced the tripple-slotted
flaps of the larger 747s.  It almost looks like a caricature of a 747,
with the huge wing and tail attached to a fat body with a hump on the
nose ... except it's far too short!  While it performed well, only 45
of the 747SP model were sold.

The -300 is a -200B with an extended upper deck to allow greater
seating capacity.  In fact, the model was first know as a -200(EUD).
Some -200B models had the longer upper deck retrofitted, and are known
at least informally as -200(SUD) models, for stretched upper deck.

The 747-400 is a very different airplane, with redesigned structures,
increased use of composites to save weight, more powerful engines that
are simultaneously less thirsty, and a glass cockpit that eliminates
the flight engineer.  Except as noted below, it has the longer upper
deck of the -300, plus winglets, which make it easy to spot.  At an
initial MGTOW of 870,000 lbs (890,000 is now available, with further
increases coming), the -400 can takeoff at a weight nearly 25% greater
than the original 747-100, yet range is nearly 1,000 miles further
than even the 747SP.

The 747-400F is the newest member of the 747 family.  In a freighter,
the longer upper deck just adds weight, so the -400F has the original
short upper deck of the -100.  At least that's what it looks like from
the outside -- there's only a stub floor behind the cockpit in the
-400F.

Finally, a series of short-range or domestic versions of the 747 have
been produced for various Japanese airlines.  The landing geat and a
few structural bits are reinforced to accomodate the greater number of
takeoff/landing cycles.  Fuel capacity is reduced and more seats are
packed in.  None of these variants have a different appearance except
for the 747-400(D), which lacks winglets.  (It does have provisions to
install them later.)  The SR/D models that I'm aware of include the
747SR, 747-100B(SR), 747-300(SR), 747-400(D), and at least two
747-100B(SR/SUD) conversions.

(There are also some military and government variants of the 747 which
I won't bore you with.)

>Also, is the 777 double decker or is it only bigger than an Airbus?

The 777 is a single deck, approximately the same width as the 747's
main deck.  Going by MGTOW, the base 777 is actually smaller than an
Airbus A340 -- at launch, the 777 base was supposed to be 505,000 lbs
(with launch customer United ordering a heavier 525,000 lb version),
while the initial A340 capability is 558,900 lbs.

--
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