BWB might be sooner than later.

dtoften

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Reuters Market News
Boeing 'Bat Jet' Could Take Off in 2006
July 9, 2002
By Emma Ross-Thomas

MADRID (Reuters) - Test flights of a revolutionary fast and fuel-efficient bat-shaped aircraft, suitable for military and commercial use, could begin in 2006, the president of Boeing (NYSE:BA - News) research arm Phantom Works said on Tuesday.

Boeing has been perfecting a plane, called the Blended Wing Body which would do away with the traditional tubular and bi-winged structure, replacing it with a giant wing and hanging belly for passengers and cargo.

Boeing calculates that a 480-passenger version of the plane would use 32 percent less fuel than a proposed A380-700 aircraft by rival Airbus, the main unit of EADS (XETRA:EADS.DE - News; Paris:EADS.PA - News).

"We're shooting for 2006 or 2007," Phantom Works President George Muellner told Reuters at the opening of a Boeing research and technology center in Madrid.

Muellner said a sub-scale demo plane, with a 35-foot wingspan would be tested next year and that a full size test run was expected to take place in 2006 or 2007.

He said commercial and military clients had shown support for the design of the plane, which as well as being energy efficient had a cruising speed of 9/10 of the speed of sound.

"The (U.S.) military have expressed an interest as a tanker (refueling) or for long range transport," Muellner said.

But financial support has not materialized from U.S. authorities or commercial clients and Boeing said it was hoping to launch a joint venture for further development of the plane.

"They've all said they like the design but they haven't put any money up yet," Muellner said.

Boeing thinks commercial clients will like the idea even more now research has shown that one of the major disadvantages of the plane -- that nearly no passenger would have a window view -- is less important than some experts had predicted.

Mike Friend, manager of programs at the Boeing Research and Technology Center in Madrid, said studies had shown passengers did not mind not being able to see out.

"We've been looking at the psychological effects of a cabin without windows. It really wasn't as much of a problem as we thought," Friend said.

Another advantage of the new design, Muellner said, was that the same design could be modified for military and commercial clients and produced in a variety of sizes.
 

sstearns2

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Everyone's going to call me a pessimist, but at this point in aircraft design the word 'revolutionary' is generally a sign of error. I spent a couple years as an aero engineer trying to make 'revolutionary' or 'innovative' ideas like this work before I decided that flying is better for the soul. There has been an enormous amount of experimentation in the last 100 years of avaition and much has been learned, but there is an alarming tendency to continue to pursue ideas that history has discredited. The Adam 'Carbon Aero' is a personal favorite example of this. The BBW is another.

The idea of a flying wing is nothing new, certainly nothing revolutionary. The idea looks great initally, but problems crop up in the details, such as pressurizing a non-cirular section. It can easily be done, but it adds a lot of weight. The 747 fuselage skin is 2 or 3 times thicker in the flater areas behind the cockpit. Tailless airplanes also have a very narrow CG range. There are other problems, which may be solvable given enough time and money, but I can't imagine that the result of all time/money/effort would be an airplane with better economics than a 777.

Scott
 

dtoften

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I agree that the design is not revolutionary but look at the military airplanes of today. Most are going towards the BWB design such as the B-1, F-16, F-18, F-22, B-2, and the newer X planes, plus the shuttle. Airplane design has not been advanced at a pace of other leading edge industries except for the metals, jet engines & electronics, IMHO and the industry needs an improved design. The 707 & 747 program had many difficult issues to challenge and they had their critics, just like BWB had their's, now. However, a 32% reduction in fuel does create a strong look at this design. Airbus, Lockheed-Martin, and Russian also have been looking at this design for the past decade. The problems with the Northrop Flying-Wing are apparently solved with the B-2 bomber. Now taking that design to a civilian airliner is what Boeing has been looking at. Your concern about the pressure vessel is correct. Other problems, among others, are public acceptance of the window-limited environment, evacuating of people within FAA guidelines, large AOA during takeoff/landing, intake of engines during large AOA, flight environment past stall, etc. If Boeing can overcome the problems of this design, which I believe they will, it will surely damage the A380 program among others. Business is money and money controlls the shots. Can't throw away that kind of fuel savings. Now, Airbus is wondering if Boeing is going to do it or not. As for the CG, it could be dealt with fuel transfer such as Airbus & Concorde does or fuel tanks could be located at the CG area. As for looks, it will grow on you and you'll say why they didn't make this years ago. :)
 

sstearns2

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Thank you for a reply with substance.

I don't think B-1, F-16, F-18, and F-22 are anywhere near flying wings and the only reason the B-2 is a flying wing is for stealth. Making a flying wing work is well within our grasp. The problem is that it's just not the best configuration for an airliner when all the details are worked out.

"Airplane design has not been advanced at a pace of other leading edge industries except for the metals, jet engines & electronics, IMHO and the industry needs an improved design."

How can you differentiate between airplane design and materials jet engines and electronics? Airplane design is materials, engines, and electronics, among other things. The 777 is far more advanced than a 737 even though it looks very similar from a distance.

Where do they get the 32% fuel savings from? Was that just from the article or do you have some more details? Do you know what they are comparing it to? For instance, the concorde was sold to the airlines as being nearly comparable to the economics of the 707, but when compared to the 747 the concorde was economically impossible.

Scott
 

dtoften

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As for the B-1, F-22, F-16 & F-18, I was stating that it is "going towards" the BWB design with the morphed wings into the fuselage, not already there with total morphed wings into fuselage but at a early stage. The B-2 is not just for stealth but lower drag, higher mach, and lighter overall weight that is adherent advantages in the BWB design which are stated in numerous articles but I have included some below for your reading :).

The airplane design vs. other technology upgrades is a subjective opinion. I look at Boeing's newest design of the 777. Don't get me wrong, the 777 is an advanced model but its advances are small compared to previous models such as 757/767 while still using the overall design that has been in use since the 707/Comet years. Another comparsion is the 737-200 with the 737-600/900. The fuselage is slightly modified and wings are redesigned. But to what measurable significance do these advancements get you compared to the engines? If I took a 737-200 with the new 737-600 engines against a 737-600 with old 737-200 engines, which would be a better airplane that airliners would buy? My bet would be on the first one since I believe (correct me if I am wrong) approximately 40% of total cost of airliners is fuel and the engines would save alot more fuel than the new fuselage.

The 32% is from Boeing PhantomWorks comparing it to the A380 airplane. Other sources have said from 20-27% and they are usually comparing it to todays convential airliner or the 747-400 depending on which article.



http://www.geocities.com/witewings/bwb/

http://members.cox.net/akecs/BWBBowers.html

http://www.galcit.caltech.edu/Seminars/Fluids/CurrentFluids/Liebeck_abs.html
 

sstearns2

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A reply with substance is again appreciated.

I read your articles with interest. My main conern is with some of their basic assumptions. They are assuming an elipitcal lift distribution across the span which leads to the minimum amount of induced drag. A conventional aircraft can get very close to eliptical due to a wing designed purely to produce the required lift with a minimum of drag. The BWB wing will have to be a comprimse between a wing and a fuselage resulting in a conciderably less efficient lift distribution.

Are they designing the BWB to the same take-off, approach, and landing speeds? A flying wing requires significantly more wing area than a conventional design to produce the same speeds. A flying wing cannot generate nearly as high of a lift coefficient as a wing with flaps and slats. The BWB has a lot of 'wing' area, but the lift per unit area is small.

A major concern I have is the failure of an outboard engine. Producing the moment to counter the good engine, without a vertical tail with a large momnent arm, is going to cause a conciderable amount of drag. The BWB will need engines which are more powerful than would otherwise be required to counter this. The more powerful engines will be heavier and somewhat less efficient in cruise.

Are they basing thier numbers on an existing engine with hard data or a paper engine?

It's difficult to tell from thier drawings, but I don't get the feeling that the BWB has the cargo volume of a conventional configuration. Cargo, FedEx/UPS overflow for example, is a conciderable source of revenue for the airlines.

The BWB configuration only works with a very large, high capasity aircraft. People need a certain amount of head room and translates into a very large chord wing. I don't think passenger airlines are heading toward larger aircraft. I think they're heading toward a larger number of smaller aircraft flying in and out of smaller airports. Hence Boeings interest in the 'sonic cruiser', a medium sized, but very long range aircraft.

Anyhow, I could go on, but my point is that there are a lot of issues they haven't addressed or fully appreciated. I'm convicned that all the problems with the BWB configuration can be worked out, but in the end it will not match the big picture economics of a 777.

Scott
 

AeroBoy

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I couldn't think of a worse design for a passenger-carrying airplane!!

Very few seats would have windows, and passengers occupying those seats could experience sudden, dramatic altitude changes. Think about it--a passenger could be 100 ft from the longtitudinal arm, and a 10 degree bank would move them about 50 ft vertically (up or down). And just how slow would you have to make those 10 degree banks so that their cup of Starbucks coffee doesn't become airborne and spill on them? How about when you're trying to intercept the final approach course, or making sudden banks to avoid other aircraft? Hope they're wearing their seat belts at all times!!!

Just my 2 cents.
 

L.A.pilot

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AeroBoy:
Think about it--a passenger could be 100 ft from the longtitudinal arm, and a 10 degree bank would move them about 50 ft vertically (up or down).
You may want to check your calculations. If you are 100ft from the longitudinal axis (not arm), a 10 degree bank will displace you vertically 100' * sin 10°-- about 17 feet. Also, it's unlikely that the passenger compartment will extend that far laterally.

Good point, however.
 
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