Should Boeing give up on it's blended wing research before it's too

late?

Lynn E. Hanover
lehanover@aol.com

I think so. The Boeing project prompted Vance's response to the

pressurization

problem in the first place as I recall. I agree with Vance.

To give one a feel for this lets say the passenger compartment is 50 feet

wide

and 50 feet long or 2500 square feet. At 144 square inches per square foot

that

is 360,000 square inches. At 10 psi pressurization differential 3,600,000

pounds

is trying to rip the roof (top of the blended wing) off or blow the floor
(bottom of the blended wing) out from under you.

Let's compare this with the pressure due to fuel weight in a conventional

wing.

Let's say fuel weighs six pound per gallon and there is 232 cubic inches

in a gallon.

That is... it weighs .0258 pounds per cubic inch.
If the wing/fuel tank is four feet or 48 inches thick that would be a

column of fuel

one inch square by 48 inches high or 48 cubic inches of fuel.
At .025862 pounds per cubic inch that would be only 1.2 psi on the bottom
wing skin by my calculations. At 3 G's that would still be only 3.6 psi.

If we break the big 50 foot square  room into smaller
rectangular rooms say ten feet wide to tie the roof and floor together you

have

cyclical stress concentrations in the corners. In other words the

rectangular

rooms want to become tubes. In addition the blended wing skins will have

waves in

them due to the deflections.  A structural engineering nightmare.
Is all this worth what ever small aerodynamic advantage one can eke
out of a blended wing design? I don't think so. Perhaps there could be
columns every couple of feet or so tying roof and floor together.

I also like to look out of the window. I don't like flying around in
a large flat room without being able to see what is going on from time to

time.

Paul Lamar

Jeff Spitzer wrote:

I agree.  I don't think the blended wing/body airliner has much of a future.

Jeff Spitzer

Dale Smith wrote:

As long as we are all weighing in on our opinions ... I'm going to go the other
way.  What is a flying wing, except the ultimate blended wing body.  Flying wings
of the 50's were way ahead of their time, as evidenced by their modern
reincarnations in the B-2.  Ultimately, a fuselage is just a waste of material, as
are tail surfaces, assuming you can make the thing stable ... and the cost of
stability has plummeted with the introduction of cheap, redundant computers.

Also, early flying wings did not have the luxury of computer design from the git
go.  Some modification of the "pure" flying wing will probably evolve, perhaps
linked by "scissors" flying surfaces, but the wasteful use of an empenage and tail
surfaces just to provide a balancing down force in back of the C.G. has already
started to wane with the increased use of canard wings.

I believe the blended wing body, or more accurately, the lifting body, with just
enough wing to keep it stable at low speed is the future of aircraft design.

Dale Smith

Think of an air mattress blown up to 10 psi :-)

Paul Lamar
 
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