NASA Environmentally Responsible Aviation (ERA) Project

fightingirish said:
Grey Havoc said:
Here's the Speed Agile's Northrop rival:
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Another link with more pictures:
AW&ST blog "Leading Edge"- New detail on flying wing airliner
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Isn't the Speed Agile concept only meant as a military transport and not an airliner?

I find all these graphics from Northrop Grumman quite alluring, but I dare not get too enthused. When was the last original airliner design built? We have had many proposals over the years that defied the rules of predictability but they all went down the drain in favor of conservative configurations. I really wish the flying wing airliner that Northrop Grumman have envisioned will come to fruition — especially because it was Jack Northrop's original vision. But when there is one flying above us and sporting the colors of an airline, I might be a great-grand father by then — if it happens at all...
 
This all looks good, but flying wings tend to have low maximum CL, hence poor STOL performance. Without a tail to trim out the pitching moment, you can't generate high CLs. The thing it has going for it is low wingloading, but that's usually bad for gust response/passenger comfort. But maybe Northrop has a bag of tricks...
 
http://www.aviationweek.com/aw/blogs/aviation_week/on_space_and_technology/index.jsp?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=a68cb417-3364-4fbf-a9dd-4feda680ec9c&plckPostId=Blog%3aa68cb417-3364-4fbf-a9dd-4feda680ec9cPost%3a98c1dc90-c072-412a-ac91-e7830ba6722a&plckScript=blogScript&plckElementId=blogDest
 

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http://www.aviationweek.com/aw/blogs/aviation_week/on_space_and_technology/index.jsp?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=a68cb417-3364-4fbf-a9dd-4feda680ec9c&plckPostId=Blog%3aa68cb417-3364-4fbf-a9dd-4feda680ec9cPost%3a98c1dc90-c072-412a-ac91-e7830ba6722a&plckScript=blogScript&plckElementId=blogDest
 

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My first question would be why? Stealth is not required for passenger planes and this is a mighty expense transport.
 
It might be due to the desire for a low wingloading and high L/D aircraft that would make Jack Northrop happy. Of course the issues would be horrible responses to flow turbulence (especially at low altitudes due to density of air) along with pitch trim issues associated with lacking a tail.
 
To me the biggest drawback is that the passengers would have to be located along the X-axis like in a conventional airplane so that the rolling of the aircraft does not offset them (the main wing containers being used for cargo/luggage/vehicles). And if you are a passenger, you may want visibility, which of course becomes a lot more complicated with a flying wing...
 
Stephane,
I've been wondering about the issue of passengers distributed spanwise and their comfort during rolling maneuvers. I haven't found any conclusive documents regarding this. It would seem that you should feel effects, like being pinned to the seat or conversely floating. The only (limited) anecdotal tidbit of information i have comes from test flights of the Twin Mustang, where pilots said they always felt like they were in the centerline of the airplane. Of course in that case they were only a few feet from the centerline. In a passenger airplane, you might be several times farther away, with magnified effects.
Anyone know more about this?
 
Whilst I applaud any effort to develop new ideas / concepts / just about anything, I can't understand why one would want a tailless airliner. Tailless platforms would seem to me to be good for [in the most part] 2 things - providing a cheap, compact, robust airframes (ie many small UAS) or with correct detail design, LO (B2, RQ170 etc etc). Elegant they may be but efficient, they are not.

I suppose, if you were to do something quite radical with airport terminal design (aircraft turntables etc - very 'Gerry Anderson' ;) ) it would be possible to have more stands, more tightly packed with tailless airliners but beyond that, I'm struggling to see advantages. There's a lot to be said for a tube with high aspect ratio wings and a tailplane...

S
(willing to be proved wrong)
 
AeroFranz said:
Stephane,
I've been wondering about the issue of passengers distributed spanwise and their comfort during rolling maneuvers. I haven't found any conclusive documents regarding this. It would seem that you should feel effects, like being pinned to the seat or conversely floating. The only (limited) anecdotal tidbit of information i have comes from test flights of the Twin Mustang, where pilots said they always felt like they were in the centerline of the airplane. Of course in that case they were only a few feet from the centerline. In a passenger airplane, you might be several times farther away, with magnified effects.
Anyone know more about this?
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Not only this but flying wings flex as well. I wonder how pronounced the "diving board" effect would be and how far out you could seat people without bouncing being unacceptable.
 
astounded that folks don't understand that Blended Wing Body (BWB) are always better airfoils. there is, in fact, nothing to be said for tube and wing craft with high aspect ratio wings and a tailplane and I don't work for Northrop Grumman.
Thank you.
 
jsport said:
astounded that folks don't understand that Blended Wing Body (BWB) are always better airfoils. there is, in fact, nothing to be said for tube and wing craft with high aspect ratio wings and a tailplane and I don't work for Northrop Grumman.
Thank you.
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Not entirely true. Flying wing airfoils are better for flying wings due to their low pitching moment, but would not work well for conventional aircraft. Everything in engineering is about compromises. It is also not correct to say that tube and wing aircraft are not great aircraft. It this were the case the airlines (who are more concerned about cost than most other groups) would not be using them. Few of the reasons that the tube and wing designs are so successful is that they are friendly for manufacturing, and hence reducing lifetime cost. They also can sustain pressurization well. In fact the pressurization issue is one of the main issues that needs to be overcome for a BWB style aircraft. These aircraft types are also easier to modify to accommodate differing sizes for a particular series of aircraft. If you look at the tube and wing style aircraft, the main thing they will do is either lengthen or shorten the design to accommodate various capacities. How would you do this with a BWB design without significantly redesigning the aircraft? This is not to say that a BWB concept might not be an ideal concept for certain missions, it is just not ideal for all missions.

Adam
 
Tube & wing aircraft are not purely lifting bodies so tubes can be assumed as drag as opposed to lifting bodies. "Conventional aircraft" can well be seen as a pejortive statement which renders all your statements questionable. Ease of manufacturing has nothing to do w/ a good aircraft for instance. Laziness does not make a good engineering arguement and even cost arguements especially if your trying to conserve energy favor BWBs. The so called Hybrid, a combination of tubular craft approaching a BWB can begin to accommodate various capacities when that is required. BWBs are still superior airfoils. Little use argueing that.
j
 
Sport, you should tell Boeing that they got it all wrong with the 787.
Seriously, the BWB was originated by Bob Liebeck and Mark Page in the early nineties IIRC, well before the launch of the dreamliner. The fact that the latter is still a wing and tube should tell you something. And i wouldn't call designing the 787 an exercise in lazyness either.


All Aeroengineer told you is common knowledge and accurate, and since he took the time to formulate a comprehensive answer, you could be a little bit more appreciative/open minded. I recommend picking up some of the excellent design textbooks (Raymer, Roskam, Torrenbeek...) and see for yourself if you don't think his arguments make sense. While everyone agrees that BWBs are more exciting, less glamorous considerations like what ends up making more money/costing less is what drives what airlines buy.
 
Aerofranz and jsport are arguing different things. A BWB may have superior aerodynamics, but airlines don't choose their aircraft on aerodynamics alone. The layout of existing airports and their aircraft handling systems, cost of developing a new type of airplane with no prior experience on similar types to fall back on, passenger accessibility (how long does it take to embark/disembark in normal situations/emergencies?), inertia ('tubes with wings is what we know') etc all factor into the airlines' decisions.
 
Will agree I got a little extreme on the aerodynamiclly superior BWB and thank you Aerofranz for the (Raymer, Roskam, Torrenbeek...) reference but will caveat by saying you can be very diligent and industrious on a technically inferior design and to that point thank you Hobbes for a better understanding on commericial preference for tubes although I did know most of the reasons for little commericial pursuit of BWBs. Think you forgot the low number of window seats being an issue for BWBs for instance:)
 
Artist's impression of Lockheed Martin Environmentally Responsible Airliner (ERA).

Lockheed Martin's advanced vehicle concept proposes a box wing design, which is now feasible thanks to modern lightweight composite (nonmetallic) materials, landing gear technologies and other advancements. Its Rolls Royce Liberty Works Ultra Fan Engine achieves a bypass ratio (flow of air around engine compared to through the engine) nearly five times greater than current engines, pushing the limits of turbofan technology to maximize efficiency.
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Source:
http://www.nasa.gov/topics/aeronautics/features/future_airplanes_index.html
 

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The first thing that comes to mind is how it will connect to the entrance passangers tunnels at the airports. Only the front doors are cleared for that.
 
... but otherwise a very nice design ! :-*
 
Matej said:
The first thing that comes to mind is how it will connect to the entrance passangers tunnels at the airports. Only the front doors are cleared for that.
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The second bridge in a dual jet bridge setup usually passes over the wing anyway. If you hooked up the second jet bridge to the #3 door in this design, it would still be clear of the upper wing.
 
rchurch said:
I'm very interested in seeing where the landing gear is with this design-
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Bicycle with outriggers in the wings?
 
http://www.aiaa.org/uploadedFiles/About-AIAA/Press-Room/Key_Speeches-Reports-and-Presentations/2012/Drake-Northrop-AVC-AIAA-GEPC2.pdf
http://www.aiaa.org/uploadedFiles/About-AIAA/Press-Room/Key_Speeches-Reports-and-Presentations/2012/Bonet-John-Boeing-AVC-AIAA-GEPC2.pdf
http://www.aiaa.org/uploadedFiles/About-AIAA/Press-Room/Key_Speeches-Reports-and-Presentations/2012/Martin-Lockheed-AVC-AIAA-GEPC2.pdf
 
Dang! anyone else having problems downloading the pdfs?
 
Any possiblity of LM getting back into the passenger jet business?
 
Hi,


the ERA project from Northrop-Grumman.
 

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