Re: Why "IGW" instead of "ER", and other question about 777's...

Date:         30 Apr 97 03:19:07 
From:         M Carling <m@ml.com>
Organization: Merrill Lynch
References:   1 2 3 4
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C. Marin Faure wrote:
>
> In article <5j8c0l$lsc@kragar.kei.com>, tassio@watson.ibm.com wrote:
>
> >    According to Boeing's web page, the range for the heaviest 777-300
> > is 6500mi, and the 747-400 range is 8290mi. I imagine the range for a
> > 777-300X will be about the same as the 747-400. Given the 777's much
> > lower operating costs, what would then be the advantage of
> > operating the 747-400 (as opposed to the 777-300X)?
>
> Range is only part of the story.  The 747 has, and always will have, more
> volume capability than the 777 (unless we make a REALLY long one :-))  So
> while versions of the 777 may be able to fly as far as the 747-400, they
> won't be able to carry as much or carry freight items as large.

A "REALLY long" 777 is possible, even with the current wing and engines.
The 777-300 is 10 meters longer than the 777-200. A hypothetical
777-400X another 10 meters longer than the 777-300 would have some
interesting attributes:

1) Such a 777-400X would have a length of 83.8 meters, just about 1.5
meters short of the maximum length an aircraft can be and still turn
around between existing terminals.

2) Aviation week has reported that given the current 777 wing and
engines, the heaviest possible MGTOW is 720,000lb. for the 777-200X and
700,000lb. and for the 777-300X. If the MGTOW for a 777-400X were then
680,000lb., and the fuel capacity were 45,220 gallons (as are the
777-200IGW and 777-300), then it would have a range of about 5-6000
miles or so. It would be possible to add fuel capacity and still have
useful payload.

3) A 777-400X could not be assembled in the factory in which Boeing
currently assembles 777s. This factory has a capacity of seven per
month. At present, the factory is booked to capacity for the next 18
months or so. If 777 demand should grow beyond seven planes per month,
Boeing would have to build another factory, which could (if so designed)
be capable of assembling longer 777s.

4) Such a 777-400X would have greater seating capacity than the 747-400.
I'm not sure which would have greater cargo capacity. The 747-400 would
have much greater range, unless Boeing were to add additional fuel
capacity to the 777.

5) Longer landing gear might be required to clear the tail during
rotation.

6) A 777-400X would almost certainly require a fifth door on each side.

M Carling