Boeing working on BWB freighter

This is the Burnelli design, a very old design called "lifting body." Boeing calls it a "blended wing body."

The Burnelli aircraft was nearly permanently taken off the list by FDR. Apparently he had dropped a name unwittingly that FDR did not like, and he was going to finance things through that name. Other defense people got money from the government. In the middle of WWII Burnelli aircraft was flown by Charles De Gaul. It is both safety effective and cargo effective. The modern industry was more lucrative constructing twice as many airplanes that burned more fuel per pound of cargo. Boeing asks about "low speed flying qualities," when that is the entire point about blended wing planes.

The government and large companies have been keeping blended wings off the commercial market for both freight and passengers at least since the early 1940s. Military aircraft have been exempt, as you see the BWB in many designs. Their patent exemption was the reason. Take a good look at an F-15 for example and many other military jet aircraft.

I have a feeling we are too often hoping for something that has simply been blacklisted, while "lifting body," design has always been safer and more fuel efficient. Aircrash.org has some very interesting insights.

Also the proper spelling is "Burnelli," not "Bernelli."

reply to post by RichardPrice



Fair enough, that makes a lot of sense. I was coming from the perspective that a freighter as big as the A380 would need to be able to load outsize or bulky loads (not necessarily all that heavy) through the front to justify itself as I don't see the need for a 300 ton parcel carrier (broadly speaking) which job the other freighters do just fine it seems. In fact the lower floor loading coupled with a lack of nose loading probably mitigates even further against this model reappearing.

reply to post by SkipShipman


Firstly a lifting body (Burnelli type design) is not the same as a blended wing design, the clue is in the name, in all Burnelli models the wing and fuselage were quite distinct and separate structures, a BWB however 'blends' these two structures apparently seamlessly from one to the other, you are saying an apple is the same as an orange here.

Secondly, lifting bodies have never been blacklisted by anybody. Military aircraft use the principle (ie F-14) because it flies well, airliners do not because of issues over pressurisation, the F-14 and its ilk are not pressurised in the lifting body section of the design. It is easier to design a pressure cylinder than any other shape and it is also lighter and stronger, which is why airliners have tubular fuselages, everything else is conspiratorial rubbish.

Originally posted by kilcoo316
The problem scales. The span is irrelevant as the stringer thickness has to reduce accordingly.

Wow, you believe that? You do realize that most aircraft use the same thickness for most of their skin, frame, and stringers. You do realize that the exceptions for this are in the wing box and tail section where larger aircraft have a lot more stress right? This is due to the poor design of the tube and wing. A BWB does not have these problems and the stress loading of the wings is spread over the entire airframe, and not to one point on the fuse lodge. And, there is no tail for the additional stress in the aft body section.

Originally posted by kilcoo316
There is also the problem of usable interior volume - I've already stated that a classical BWB does not work on a small scale.

ERRT Wong again. If you would have taken the time to read some of my past links you would have realized that this is all wrong. Due to the blending of the wing and body, a BWB has more useable interior space. And the X-48B IS A SMALL BWB and the data from Boeing test flights are falling in line with their flight simulator data.

Just because you stated it does not make it a true statement. Please read the following links:
Skyray 48 Takes Flight
"One of the latest cutting-edge experimental aircraft, or X-Planes, the X-48B BWB is a collaborative effort of the Boeing Co., NASA's Fundamental Aeronautics Program, and the Air Force Research Laboratory. The 21-foot wingspan, 500-pound, remotely piloted plane is designed to demonstrate the viability of the blended wing shape. And demonstrate it has."

I would say that is a small BWB wouldn't you?

"NASA is interested in the potential benefits of the aircraft - increased volume for carrying capacity, efficient aerodynamics for reduced fuel burn, and, possibly, significant reductions in noise due to propulsion integration options. "

What part of “increased volume” do you not understand?

Originally posted by kilcoo316
A lifting fuselage type may work, indeed, from stuff I've done in the past, it does work... kind of. The passenger version had no advantage over contemporary cigar designs, but the freighter version allowed for use of large LD3 & LD6 containers, so a company like fedex or DHL can use them on the spoke of a network without having to switch containers.

ERRT…Wrong again. The most common container for freighter companies (like FedEx, UPS and DHL) are AMJ, SAA and AYY containers. LD3 & LD6 are used for belly loading and are utilized by freighter companies, but it is not their primary container type. These are used more by passenger airliners as they use their belly compartments to move freight. A large BWB can take ISO containers.
La rge BWB Freighter Study by Boeing

Originally posted by kilcoo316
Not if it cannot wrap onto the fuselage it can't (because the other wing will be hitting the terminal.

If you would have taken the time to read the “How it works” link I posted you would have seen this image:



As you can see the super big BWB would fit in the same area as a 747-400. You would not have any problems as you just dont pull the BWB all the way FWD as the 747. Then it is simply of adjusting the "Skywalk" a little aft and inboard to mate with the BWB door. The wing would not intrude on otehr aircraft, and the air stairs would mate just fine.

My profession is in aircraft engineering, and I have had 8110's & STC's approved by the FAA as a part of my job. Do you even know what an 8110 or STC is?

More Info:
NASA Large BWB Fact Sheet

This two page fact sheet states that a large BWB would be able to be operational from standard airport terminals, and its states that a BWB has more payload and cargo volume.

This is from 2003, and from what I know the pressure issue has been worked out by the use of materials, and structure by utilization of bulkheads, and column structures. Similar to large ships and submarines.

If the "Tube and Wing" design is the be all and end all of aviation, then why are there not any birds that use that design? And yes, bird can fly at high altitudes.
How High Can Birds Fly?

So please provide me your proof that a BWB has less useable interior volume. I would also like to know why there are not and "Tube and Wing" birds since that design is so superior? Most birds I see look more like a BWB.

Originally posted by MrKnight

Wow, you believe that? You do realize that most aircraft use the same thickness for most of their skin, frame, and stringers. You do realize that the exceptions for this are in the wing box and tail section where larger aircraft have a lot more stress right? This is due to the poor design of the tube and wing. A BWB does not have these problems and the stress loading of the wings is spread over the entire airframe, and not to one point on the fuse lodge. And, there is no tail for the additional stress in the aft body section.

Sorry, my sentence was poor.

The skin stringer pitch will probably remain constant, with that fairly consistent loading distribution the skin size will also probably remain similar.

The stringer and frame does not stay the same, it cannot stay the same - what on earth gave you that idea? You cannot have a 3 metre diameter fuselage with the same frame thickness as a 1m diameter fuselage. Same for length, a 100 m long fuselage will have thicker stringers than a 50 m long fuselage.

The increasing size is not linear due to area distribution for a scaling fuselage with constant diameter:length, ok , but it does increase.

Originally posted by MrKnight
ERRT Wong again. If you would have taken the time to read some of my past links you would have realized that this is all wrong. Due to the blending of the wing and body, a BWB has more useable interior space. And the X-48B IS A SMALL BWB and the data from Boeing test flights are falling in line with their flight simulator data.

Tell ye what kid - you explain to me how something that blends into a thin wing can have usable headroom. Particularly on a small scale.

I have read some of your links, others I've seen before, and I've read technical papers on conceptual BWBs that aren't linked here. Not one of them dealt with this issue - which is expected as its a geometric constraint and you either go lifting fuselage, or accept the penalty. Your subsequent link later on in this thread explains how they get more "usable space".

Originally posted by MrKnight
Just because you stated it does not make it a true statement. Please read the following links:

I would say that is a small BWB wouldn't you?

"NASA is interested in the potential benefits of the aircraft - increased volume for carrying capacity, efficient aerodynamics for reduced fuel burn, and, possibly, significant reductions in noise due to propulsion integration options. "

What part of “increased volume” do you not understand?

Oh my good god... quit acting like a 5 year old and read your own links!!!

Its a MODEL - your acting as if you could fit 30 people inside the model.

The model will SCALE - to a LARGE size - broadly equivalent to 1.5 times the MTOW of the A380...


Yet according to you it works on a small scale!

Originally posted by MrKnight
ERRT…Wrong again. The most common container for freighter companies (like FedEx, UPS and DHL) are AMJ, SAA and AYY containers. LD3 & LD6 are used for belly loading and are utilized by freighter companies, but it is not their primary container type. These are used more by passenger airliners as they use their belly compartments to move freight. A large BWB can take ISO containers.

Your point is?

Are LD3 & 6 used by both freight and passenger lines (including FedEx, UPS and DHL)? Yes.

Can a lifting fuselage allow easier transfer of cargo from large plane to small plane? Yes.

Originally posted by MrKnight
If you would have taken the time to read the “How it works” link I posted you would have seen this image:

And now you have to modify every skywalk in the world.

You have to pull the BWB further forward than the 747 otherwise the skywalk won't reach the door.

Originally posted by MrKnight
My profession is in aircraft engineering, and I have had 8110's & STC's approved by the FAA as a part of my job. Do you even know what an 8110 or STC is?

PMSL - your absolute ignorance on all matters regarding certification convince me not in a 100 million years have you worked on designing aircraft!!!

You can talk till your blue in the face now, google won't change what you've already posted!

[edit on 16/10/07 by kilcoo316]

Originally posted by MrKnight
This two page fact sheet states that a large BWB would be able to be operational from standard airport terminals, and its states that a BWB has more payload and cargo volume.

Yeap - a LARGE one.

Originally posted by MrKnight
This is from 2003, and from what I know the pressure issue has been worked out by the use of materials, and structure by utilization of bulkheads, and column structures. Similar to large ships and submarines.

Ahhh, google is no substitute for knowledge my boy. Any aircraft engineer would immediately realise that ships and submarines have no weight limitations.

If your referring to new materials, like those on the B787 or A350, well, those (along with aerodynamic & propulsion improvements) have already resulted in ~20% efficiency increases over the A330.

Originally posted by MrKnight
If the "Tube and Wing" design is the be all and end all of aviation, then why are there not any birds that use that design?

Do birds have to fit smaller birds inside the fuselage? (offspring for instance) No

Do birds have to operate with interior pressures significantly above ambient? No

Do birds need lateral room for muscles? Yes


Ask yourself the fundamental questions, and you'll see why they can be blended.

Originally posted by MrKnight
So please provide me your proof that a BWB has less useable interior volume.

What?

You need a web link before you'll believe that simple geometric limitations apply? *BTW, I am saying that a SMALL BWB has less interior room*



Look kid - if the 'fuselage' blends into a thin wing, by definition that means you either have:

1. a seriously thick wing at the root -> alot of drag.
2. or a very small 'cabin' at the root -> no headroom at all.


By scaling the thing up, you can get acceptable thickness for cabin height at the wing root while maintaining a reasonable thickness/chord ratio.

Wow, you have no imagination. I come across your type all the time. No wonder there has not been any real advancement in aircraft design in the last 50 years. I wish I could post everything I know on this forum, but I can't.

Yes it will work on a smaller scale. Think outside the box (or tube in this case).

You keep talking about weight, but a BWB is not as concerned about weight due to the amount of lift of the body, and wings. You can calculate the entire area of a BWB for your wing loading and lift. Your wing loading factors are not as critical due to the integration of the wing to the body.

If you did read all of the links I provided, you would realize that. That is why BWB's can carry more payload, and have more internal volume. If you can not get that fundamental principle then you will never understand a BWB.

Laugh all you want, and doubt all you want, you can not stop progress with your lack of imagination.

I know it is only a matter of time before you are proved wrong. I am very patient, and I am no kid.

This reminds me of something... Something about rotating pylons?

No wonder there has not been any real advancement in aircraft design in the last 50 years.

Just jet engines, supersonic travel, delta wings, forward-swept wings. Nothing important.

You keep talking about weight, but a BWB is not as concerned about weight due to the amount of lift of the body, and wings. You can calculate the entire area of a BWB for your wing loading and lift. Your wing loading factors are not as critical due to the integration of the wing to the body. If you did read all of the links I provided, you would realize that. That is why BWB's can carry more payload, and have more internal volume. If you can not get that fundamental principle then you will never understand a BWB.

Yes, BWB's can carry more, indeed. They are very efficient at lifting things. But, of course, there's a catch. While cargo can take a lot of forms, people have a pretty regular size. I think we can safely say that we dislike it when our heads must be tilted to the side throughout an 8-hour flight because the aircraft is not quite tall enough. This is fine, but in order to make a BWB (which have a relatively thin shape) able to carry enough people for it to be efficient, it's going to have to be huge. Monstrous. To put it bluntly, when you want to carry massive amounts of people in a BWB it's going to end up being an unwieldy beast.

Example. Look at the picture you've provided us with. That entire centre section of the Tube-and-Wing can carry passengers, or what have you. The BWB can only fit stuff in places where it is high enough to carry them. Remember, the wing near the ends is rather thin, and it must also taper off at the rear edge of the aircraft. And how much of that is taken up by essential support equipment? Flaps? Actuators? Fuel? Engine Systems? And how much of it is capable of holding people comfortably?

Even then, how will the infrastructure support such massive aircraft? How will you fit them at gates? How can you control such a beast on the taxiways with other aircraft? How controllable will something so big be on final? And other questions.

Laugh all you want, and doubt all you want, you can not stop progress with your lack of imagination.

Where is this progress of which you speak?
Where are our attempts to stop said progress?
Where is our lack of imagination?

I know it is only a matter of time before you are proved wrong. I am very patient, and I am no kid.

I can't say I honestly believe you are an engineer. You may not be a kid, but a professional in aeronautical engineering seems unlikely.

Originally posted by MrKnight
and not to one point on the fuse lodge.

Here is a cross section, and plan view of the 800-1000 passenger BWB. The 260' big one. As you can see it has two decks.

If one were to scale that down in half, to have a 130' wingspan, you would still hve a center body thickness largeenough for people to walk around in.

So, yes a small BWB would be thick enough for people to walk around in or to carry freight.

And as you move outboard, and it starts to narrow, you can use that area for what you would normally place in your lower deck of a tube.

A BWB will orrfer wide open floorplans, more seat, and if need by sun roofs.

You don't have to believe that I am an aircraft designer and engineer but I am. I am not a writer, and I suck at typing but that is becsue I spend most of my time working in 3D, and 2D design programs.

Almost imagine that you have three tubes side by side, the two outboard are slightly smaller in diameter. the center diamers is similar to a traditional large aircraft, and the two smaller are slightly smaller. Then place a flat top and bottom connecting the three tubes, and you can start to see how a BWB would compare to a tradition tube. The area between the tubes can then be interperted as columns or bulkheads. if you can visulize that, you can start to realsize how a BWB internal structure would be desinged. Similar to the bottomview above and this below:



These two images came from these two sites, which show all sorts of variation to the BWB.

The Wing Is The Thing

And

Future Airliners

If the 260' BWB can take 800 people and you scel it by 50%, which will reduce the thickness to one deck, and half the span, you can reduce the number of passenger by .25, or a total of 200 in an aircraft of 130' wingspan.

Now comapre that to similar sized aircraft: CRJ-900

The new CRJ 900 can only take about 90 passengers, and has a wing span of 120' but would be about twice as long as the 1/2 scale BWB.

So you are now talking about and aircraft with about the same span, and about half the legnth can take twice the passengers. I would also be willing to bet that you could power the BWB with similar engines and use 20-30% less fuel. Twice the payload, which less operational cost.

It is not a matter of if, it is when. When the first BWB enter service, it will begin a race in every market.

Get out out your drafting equipment or design software and prove me wrong. Or just use your handy pocked calculator, and apply basic logic.

A pressure is pressure, and if you can apply pressure to one tube, you can apply it to three side by side. It is not much more complicated than a swimming pool raft. Each chamber is a tube of air connected to another chamber.



Same theory differnt application



Now just imagine that the base of the pressure raft makes up the chambers of the delta wing BWB, and you are in it. Not much more difference than a single tube of air in that raft with two wings strapped to it, except that the center body give you lift, and decreased drag.

Originally posted by MrKnight
Wow, you have no imagination. I come across your type all the time.

Same old pish spouted by people that think they are on to something when practicalities are brought in.

Originally posted by MrKnight
Yes it will work on a smaller scale. Think outside the box (or tube in this case).

You keep talking about weight, but a BWB is not as concerned about weight due to the amount of lift of the body, and wings. You can calculate the entire area of a BWB for your wing loading and lift. Your wing loading factors are not as critical due to the integration of the wing to the body.

A BWB is not quite the aerodynamic marvel (compared to current designs) that you think it is. Your swapping lift dependent drag for wave drag and skin friction drag (a BWB having a larger wetted area, a larger frontal area and much more adverse curvature on the fuselage).


Indeed, most current work is aimed at reducing lift INdependent drag, as it is the area where most improvement can be made.

Originally posted by MrKnight
If you did read all of the links I provided, you would realize that.

You speak of these "links" as if they are the bible. Guess what, they don't talk about structural issues, they don't talk about certifying the pressure cabin, they don't talk about certifying fatigue on the airframe, they don't talk about alleviation of the roll problem associated with placing passengers far from the rotational axis etc etc.

Originally posted by MrKnight
That is why BWB's can carry more payload, and have more internal volume. If you can not get that fundamental principle then you will never understand a BWB.

Yeap yeap... a BIG BWB can carry more people and cargo.

A small one does not have more USABLE internal volume. You seem unable to grasp that.


BTW - just realised you talked about using bracing structures for the large radii sections - the stress concentrations don't occur there, they occur at the junctions between the different radii.

But, being an aircraft engineer you should know that (just as you should know what a coordinated turn is, and the obstacle certification presents to getting radical stuff onto aircraft quickly).

Originally posted by MrKnight
I know it is only a matter of time before you are proved wrong.

I am not doubting BWBs will arrive at some stage for something (heck, the B-2 is a BWB of sorts). This time-frame however:

Originally posted by MrKnight
I am willing to bet that a commercial freighter bwb will be in service in the next 6-10 years

Is simply stupid... ridiculously so.



[edit on 18/10/07 by kilcoo316]

Originally posted by MrKnight
Here is a cross section, and plan view of the 800-1000 passenger BWB. The 260' big one. As you can see it has two decks.

What design is it from?

What is the root t/c ratio? From that sketch provided the t/c is about 0.215.


Do you have any idea what that infers for wave drag?

Originally posted by MrKnight
If one were to scale that down in half, to have a 130' wingspan, you would still hve a center body thickness largeenough for people to walk around in.

No no no.

That fuselage height has to nearly half (while keeping the root chord length constant) to get down to usable t/c ratios.

Originally posted by MrKnight
These two images came from these two sites, which show all sorts of variation to the BWB.

Look man, sketches do not represent finalised engineering drawings - once again, the t/c ratio of that 'fuselage' is ridiculous. Please quit trying to use them as some sort of 'proof'.



I'll not bother commenting on your extrapolations from the 260' BWB, as the basepoint you use is fundamentally flawed.

I'll also not say much about your swimming raft... do you not even realise they are closed 'cylinders' apart from one end?

I know they are cylinders, I was hsoing that you can pressure the interior of a BWB by using a series of chambers.

All you do is say that it will not work. You offer no solutions or anything of any value to the topic. Prove to me that it will not work, under what authority do you speak from?

I post articles and links to papers written by the authorities on the subject. I need not be an authority as I post the data, and desing scketches from the people that are authorities on the subject.

Prove to me that NASA, DARPA, Boeing Phaontom Works, and all of the outher authorities that I quote, and post technical data from are wrong. If you can not substantiate your views, then you offer nothing to the disscusion, and are nothing more than a doubting distraction.

In 6-10 years you will be proven wrong.

X-48B Test Flight

In case you have not noticed, UAV that are of blended wing design are proving to carry more payload and have better range than "tube & wing" of the same size.

Polecat UAV

X-45A

X-47B

I am waiting for you to come back and give me some excuse as to why these UAV do not prove the value of a BWB on a small scale. Of course you will offer no proof or have any reason except your own word.

Show me any and tube and wing their relative size, and show me where they can have the same range a capabilities as these UAV blended wings.

Look up the MQ-1 Preator and the X-47. They both are about the same legnth and width, but one has more speed, more range, and more payload capability.

How would this account for your theroy of a blended wing on a "small" scale?

Originally posted by MrKnight
I know they are cylinders, I was hsoing that you can pressure the interior of a BWB by using a series of chambers.

All you do is say that it will not work. You offer no solutions or anything of any value to the topic. Prove to me that it will not work, under what authority do you speak from?

This is like talking to a brick wall.

I'm saying it won't work easily - how the hell can I offer a solution when I'm saying it won't work?


Of course there are approaches to minimising weight growth, NASA & Boeing are working on them at the moment. But they are still experiencing substantial weight growth above a A380/B777 comparative aircraft.




As for my experience in the area:

I spent 6 months on conceptual work of a new design regional jet where radical alternatives to current fuselages were considered (yes, it included a BWB).

At the trade-off it was clear that the conventional tube and wing was best. However, for pure research reasons we decided to develop the next best design a lifting fuselage that meant we could dispense with alot of high-lift gear in the wing.

It didn't work out as good as the tube/wings except for allowing wide-body containers to be used. The BWB was dismissed as being even worse for packaging reasons.

Originally posted by MrKnight
I post articles and links to papers written by the authorities on the subject. I need not be an authority as I post the data, and desing scketches from the people that are authorities on the subject.

You posted links to internet sites and sketches... howstuffworks is not an authority on the subject.


The only link of any worth is the Boeing (Liebeck) one regarding the presentation. However, I've read the journal paper its based on.

There were several design details that heavily influenced the conclusions:

1. Engines buried in the wing - that has not been done for a long time for good reason. Airlines and the FAA/JAA will have a fit over it for various reasons.

2. I quote:

Thus, the early study began
with an attempt to use circular cylinders for the fuselage pressure
vessel, as shown in Fig. 3, along with the corresponding first cut
at the airplane geometry. The engines are buried in the wing root,
and it was intended that passengers could egress from the sides of
both the upper and lower levels. Clearly, the concept was headed
back to a conventional tube and wing configuration. Therefore, it
was decided to abandon the requirement for taking pressure loads
in hoop tension and to assume that an alternate efficient structural
concept could be developed. Removal of this constraint became
pivotal for the development of the BWB.

Originally posted by MrKnight
Prove to me that NASA, DARPA, Boeing Phaontom Works, and all of the outher authorities that I quote, and post technical data from are wrong.

They aren't wrong - I've never said they are wrong.

They just aren't right enough yet, and won't be for quite a few years. After that, a demonstrator (maybe a military cargo lifter) will have to be built and flown for a long time to satisfy the authorities.

Originally posted by MrKnight
In 6-10 years you will be proven wrong.

I cannot stress enough how much that is wrong.

20-30 years, they might be ferrying passengers... maybe.

Originally posted by MrKnight
In case you have not noticed, UAV that are of blended wing design are proving to carry more payload and have better range than "tube & wing" of the same size.

None of which have pressure-hulls...


Going in circles here - I'm telling you why it won't work yet and you come up with ever more absurd examples to try and prove me wrong, this is another.

Originally posted by MrKnight
How would this account for your theroy of a blended wing on a "small" scale?

Tell me... is it easier to package electronics where they can be broken down into many smaller components, or humans, who might object to being broken down to fit inside a confined section of the interior.


[edit on 18/10/07 by kilcoo316]

Originally posted by MrKnight
All you do is say that it will not work. You offer no solutions or anything of any value to the topic. Prove to me that it will not work, under what authority do you speak from?

The authority he speaks under is the fact that he has consistently given intelligent, useful, and above all true discourse in the past on this site. Therefore, on this site, his word is considered valuable enough take at face value. If you still don't want to believe, try looking it up on the internet or at a library. Chances are pretty good you'll find his arguments pretty convincing.

In case you have not noticed, UAV that are of blended wing design are proving to carry more payload and have better range than "tube & wing" of the same size.

Please notice that these UAV's are not designed to carry people. Hence, the U in front of the AV. In order to be a feasible option for moving people, it would seem logical that the aircraft in question would have to be able to carry a significant amount of people, enough to make it worth the cost of fuel and maintenance. Carrying equipment for military uses and carrying people for movement purposes are two very different things.

So are a very small BWB and a very alrge BWB.

I am waiting for you to come back and give me some excuse as to why these UAV do not prove the value of a BWB on a small scale. Of course you will offer no proof or have any reason except your own word.

We have a 2 for 1 deal on ATS. You get our word, and logic attached as a free prize with purchase!

Show me any and tube and wing their relative size, and show me where they can have the same range a capabilities as these UAV blended wings.

Let's try something easy. Look at a Tube-and-Wing design. Then look at a BWB design. Take a peek at the front-on view. That BWB's looks a bit big, doesn't it? There's gonna be a load more drag on the big, wide body rather than the thin, long one. Lots of drag on that big, wide body. Much less drag on the Tube-and-Wing. How do you think that reflects on the speed of the aircraft? How do you think that would affect the fuel efficiency of the BWB if both aircraft were maintaining the same speed and altitude? Answer: The BWB needs more energy to obtain and maintain the speed at constant altitude. More fuel consumed. Now, although it can carry more, this is moot since the airline companies detest spending money rather than making money. And fuel, fuel costs money.

Look up the MQ-1 Preator and the X-47. They both are about the same legnth and width, but one has more speed, more range, and more payload capability.

Have you noticed that the faster one has a jet attached, rather than a propeller? The MQ-9 has a 101 horsepower engine, versus a jet. The speed doesn't come because the aerodynamics have changed.
Have you noticed that range happens to go up as the airframe gets significantly faster?
Have you noticed that the supposedly higher payload on the X-47 is not actually higher? The MQ-9 can carry ordinance. The X-47 does not carry ordinance. Even could the X-47 carry ordinance, the MQ-9 can carry a total of about 1700 kilograms (~4800 kg maximum - ~1700 kg empty) of fuel and whatnot, while The X-47 can carry 1000 kilos (~2700 kg max - ~1700 kg empty).

Ultimately, your comparison of two aircraft which differ significantly more that in just the aerodynamics doesn't hold water. The best way to test this would be to take each of the different shapes, put the same amount of power on 'em, wind 'em up, and let 'em go.

Trust me I look at BWB's all the time, and I understand the additional drag of the "wetted" area, but the center body of a BWB contributes more lift. This lift out weights that minor drag increase of the blended wing vs. the "wetted" area of the tube.

The tube on a traditional aircraft offers little to no lift, and is all drag. That is why you do not add the area of the tube into the "wing" area for lift.

On a BWB you have much better lift and a much cleaner design. You don't have to "take" my word, you can go and look that the research of NASA and Boeing.

“Boeing has conducted studies showing a BWB aircraft would be about 80 percent of the gross weight of a conventional aircraft designed to perform the same mission. The aerodynamic efficiency of the concept, uniformly distributing the lift over the total span of the aircraft including a lifting fuselage, requires about 30 percent less fuel to accomplish the mission.”

Fuel Efficient Flying Wing

See, this is called supporting my position. I don't believe the "because I say so" method.

Blended Wing Body Research Aircraft Flies

"The Boeing BWB design resembles a flying wing, but differs in that the wing blends smoothly into a wide, flat, tailless fuselage. This fuselage blending helps to get additional lift with less drag compared to a circular fuselage. This translates to reduced fuel use at cruise conditions. And because the engines mount high on the back of the aircraft, there is less noise inside and on the ground when it is in flight."



If one design is better on a small scale, and on a large scale and the deisgn features can take the same items on the medium scale, it will have those same advantage on the medium scale.

If you scale the double decker in half, it becomes a single level aircraft, with more volume. True, you will not have a belly cargo area, but you utilize the inboard area of the wing for cargo stowage, where it is too thin for people bug bigg enough for baggage and cargo. There is no "round walls" in a BWB as the round parts where the wing blends will stow the cargo.



Throw in some sun roofs for cloud watchers and your in business.

Now for the UAV, where you are again wrong. (That is why it is you post your sources).

MQ-9 B:
Length 36 ft
Wingspan 66 ft
Weight 10000 lb
Payload 800 lb Internal 3,000 lb External (3,800 Total)
Speed 220kt
Ceiling 50,000 ft
Ferry Range 400 nm

X-47B:
Length 38.2 ft
Wingspan 62.1 ft
Weight 42000 lb
Payload 4,500 lb Internal
Speed High subsonic
Ceiling 40,000 ft
Ferry Range 3500 nm
Combat Radius 1,500+ nm Strike

The X-47B have more payload, range and speed and is similar in size. one is a tube with wings, the other a blended wing design.

Interesting read:
UAV Article

The X-47B's design mission is more inline with that of the MQ-9 B "Reaper", which is a UAV that has strike capabilities. In order to acheve the utilization of the MQ-9 "Predator" a BWB would be superior, but there is not one out there currently that has been designed for that role. If it were it would likely have a prop engine, as it would use less fuel to keep aloft, but a BWB would be able to stay up longer, and have more "spy' equipment in it as it would need less fuel for lift, and could carry more payload.

Oh, and I haven't even touched on the natrual inherant stealth properities of a BWB. The shape in of it's self has more stealth properities, even if it is not designed for stealth.

The X-47B have more payload, range and speed and is similar in size. one is a tube with wings, the other a blended wing design.

Like I said: You simply cannot compare the range and speed due to the way the aircraft are designed. Whether the difference is due to the aerodynamics we cannot say, it is ambiguous since the engines are so radically different. For all we know, a higher-powered engine could actually provide more thrust (and thus more speed) for the X-47! Since such wild-eyed claims cannot be proven or disproven, we are therefore required to say that there is no way to say whether or not it is the aerodynamics doing this. Unless we fit the same engine to both airframes, all we can offer is speculation on whether or not being a BWB allows a very large increase in speed, or whether it is the mere by-product of a convenient engine type.

However, one thing I must point out is that your presentation of the payload is nothing other than wrong.

X-47B:
Payload 4,500 lb Internal

This is a misrepresentation of the facts. See the below.

Weights
Empty Weight 1,740kg
Fuel Weight 472kg
Maximum Fuel for Extended Missions 717kg
Maximum Take-Off Weight 2,678kg

As you can see, there is no source for this. None whatsoever. Anyway, as you can see, the empty weight is 1740 kg. This is the weight of the aircraft while it sits there on the floor. No fuel or ordinance. Just the aircraft. What we want is the max take-off weight, which tells us the maximum amount of X it can carry. From my mere brain-based calculations, that looks like a total of 938 kilograms worth of junk that can fit on it. That includes fuel, ordinance, extra cupholders, and everything. Here's something cool.

Weight: 4,900 pounds (2,223 kilograms) empty
Maximum takeoff weight: 10,500 pounds (4,760 kilograms)

That's for the MQ-9 Reaper. Here we have the Max takeoff weight, and the empty weight. According to my meager brain, that ends up at 2537 kilograms of extra fun that can be attached. 2537 kg... 938 kg... But the X-47 is so much cooler!

Again without the sources.

Oh, and I haven't even touched on the natrual inherant stealth properities of a BWB. The shape in of it's self has more stealth properities, even if it is not designed for stealth.

Please do. I would very much like to see these inherent stealth properties. Particularly when compared to a Tube-and-Wing combat aircraft.

[edit on 10/18/2007 by Darkpr0]

Originally posted by MrKnight
Trust me I look at BWB's all the time,

Looking at pretty sketches and concept drawings does not equate accumulating knowledge.

Originally posted by MrKnight
The tube on a traditional aircraft offers little to no lift, and is all drag. That is why you do not add the area of the tube into the "wing" area for lift.

True.

Originally posted by MrKnight
On a BWB you have much better lift and a much cleaner design. You don't have to "take" my word, you can go and look that the research of NASA and Boeing.

True - although I do have concerns over the wave drag.

Originally posted by MrKnight
“Boeing has conducted studies showing a BWB aircraft would be about 80 percent of the gross weight of a conventional aircraft designed to perform the same mission. The aerodynamic efficiency of the concept, uniformly distributing the lift over the total span of the aircraft including a lifting fuselage, requires about 30 percent less fuel to accomplish the mission.”

By neglecting the pressure hull issue, and assuming they can make a cabin of the same weight:volume ratio of a conventional tube.

I've already stated that clearly in my previous post.

Originally posted by MrKnight
Fuel Efficient Flying Wing

See, this is called supporting my position. I don't believe the "because I say so" method.

Thank you for that graphic, now... does that not do more to support the position of BWBs being unnecessary or what?


Assuming an equivalent efficiency pressure cabin design, the BWB has a 6% lower gross weight.

Now, in reality its gross weight will probably be 10% more than the conventional design

So its 21% fuel savings will drop down to something around 5-10%. [Note that 20% sfc savings is the "magic number" where manufacturers deem a new aircraft worth developing]




Anyway, back to this 6-10 year thing and certification, a normal wing has to pass many regs, 2 of which are ultimate failure loading and fatigue cycle testing.

Currently these are performed on massive (and extremely expensive) custom made rigs. Loading of a wing is relatively simple, the root can be constrained at the spars (as they are the load-paths) and the loading applied proportionally across the wing.


How do you propose loading up the BWB to simulate either of these cases (bearing in mind every single frame along the centreline is a loadpath for the 'wing')?

This is what the FAA or JAA will ask anyone building a BWB, and their answer better be good or else no plane.




Certified within 10 years?

[edit on 19/10/07 by kilcoo316]

If you noticed, I provide the links for my number on the X-47 B

X-47 UCAV - Global Secuity


X-47 UCAV

X-47A X-47B
Length 8.50 m (27.9 ft) 11.6 m (38.2 ft)
Wingspan 8.47 m (27.8 ft) 18.9 m (62.1 ft)
Weight (gross) 2500 kg (5500 lb) 19000 kg (42000 lb)
Payload 4,500 lb (2,045 kg) Internal
Speed Subsonic High subsonic
Ceiling 30,000+ ft (+ 9.2 km)
12200 m (40000 ft)
Ferry Range 6500 km (3500 nm)
Combat Radius 1,500+ nm Strike

Another payload Source - 4,500 lbs

Another payload Link: 4,500 lbs

Yet another link.....4,500 pound payload
"Despite being only a few feet thick, its maximum payload will be 4,500 pounds and it will carry 8 Small Diameter Bombs, Boeing's newest near-precision 250-pound weapon. This revolutionary combat vehicle will fly at 40,000 feet with a mission radius of 1,300 nautical miles."