Re: Blended-body snag?

Date:         13 Feb 97 01:37:36 
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Joules Potter <> wrote:

>Nobody has yet mentioned fuel storage.
> A 747-400 can hold a max of 173000kg(382999lbs) of fuel, which should
>get it LHR-HKG for example. Taking into consideration new engine
>developments which lead to better fuel consumption, to have any sort of
>range this aircraft is going to have to carry, or have provision to
>carry, a lot of fuel. So where are they going to put it?

Why not put it in tanks in the wing - just like conventional aeroplanes?
One thing flying wings have never lacked is fuel tank space.

>Modern engines are tending towards higher and higher bypass ratios, can
>you imagine 4 next generation RR Trent/GE engines mounted internally?

No.  But then only a few designers ever did imagine that with any
jet engine and they stopped it a long time ago.

>Quite apart from the size of the engine, the intake/exhaust ducting
>would be enourmous, having to pass through the length of the aircraft,
>disrupting the passenger carrying compartment and creating even more
>structural questions.

The Independent's picture seems to show the engines mounted at
the rear without ducts of any serious length.  There did seem to be
some shrouding arrangement which might point to some boundary
layer jiggery-pokery.

>>>their circular fuselage does not distort with pressurisation -
>>>(though the Comet III exploded nonetheless!)

Comet I actually.

>Unless there are some real wayout advances in all aspects of aircraft
>construction, eg materials, engines etc, then this incredible flying
>machine IMHO will never get off the drawing board and into the air as a
>commercially viable passenger aircraft.

I would have thought that nobody was brave enough (as Sir Humphrey
might put it) to say such things any more.  It was said about the 747,
it was said about the 707, it was said about the B-47(except the
commercially viable bit), it was said about the B-29 (ditto comm.
viable), it was said about the 247...  Are you the guy that made
Anthony Fokker put wing struts on the DVIII?

We've had 93 years of almost continuous 'real way out advances
in all aspects of aircraft construction' especially 'materials engines
etc'.  With the new lightweight alloys, the experience Boeing and
MDD now have in composite structures and the new big engines,
it seems entirely feasible.

The major problem would actually seem to be deciding whether the
aerodynamics are reliable enough to risk the huge investment which
will be required or whether a more conventional solution is a better
place to put $15-20 billion.  Aerodynamics seems to be what made
Boeing.  It will be interesting to see if (with MDD) they still have
that edge.

>It could perhaps go the way of Concorde instead.

It could perhaps go the way of the 747.  It'll be interesting to see
if the current generation is made of the same stuff as Bill Allen.

Graeme Cant