Re: Blended-body snag?

Date:         13 Feb 97 01:37:35 
From: (Filip De Vos)
Organization: University of Ghent, Belgium
References:   1 2
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Joules Potter ( wrote:
: In article <airliners.1997.378@ohare.Chicago.COM>, adopt
: <> writes
: >In article <airliners.1997.317@ohare.Chicago.COM>,
: >(Ostreger) wrote:

: >Not a technical answer... but do wonder if a design could be
: >similar to a submarine.  The guts of the passenger/flight crew
: >pressure shell could still be cylinderical... although blended
: >with the whole 'wing'.

: Sounds like a good idea, maintain a pressurised semi-monocoque shell
: within the unpressurised remaining wing area.

That does not sound like a good idea to me. You would lose an awful
amount of space.

: 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?

Well, at the back-end of the wing, close to the flaps/ailreons/elevators
(flapervators?) the internal height will get too low for a passenger
cabin. So the fuel can be put there. Another place would be over the
passengers' heads. Fuel being a liquid, it can be put anywhere fixed
stuff cannot.

: What about the engines?

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

Why 4? Considering a flying wing will be more aerodynamically efficient
than a classic plane, perhaps you can only use three or better, two. Two
is enough for the 747 sized 777. Alternatively, giant Trent/GE90 sized
mills can be shunned for handier CFM, IAE or PW2000 units.

: 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 McDac model did have the engines above the fuselage, on pylons. No
air-duct carry-throughs there.
Another place for the engines is the back, with the intakes over the top
of the center wing/body. Seems boundary-layer air slowed by the upper skin
is OK for engine intakes.

: 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. It could perhaps go the way of
: Concorde instead.

Yep, building the dang thing will likely be much more costly than making
a classic plane, enspecially since most classic plane constructiuon
investments will not be usefull.

Stretching it becomes well-nigh impossible.

Filip De Vos                  Better, Faster, Cheaper means *NO SHUTTLE*                 -Cathy Mancus-