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MIT/Cambridge To Unveil "silent" Flying Wing 11/06  
User currently offlineLemurs From United States of America, joined Mar 2005, 1439 posts, RR: 4
Posted (7 years 8 months 4 weeks 1 day 20 hours ago) and read 4545 times:

http://www.msnbc.msn.com/id/15580898/

I wonder what they've done to address the vertigo issues that most past studies have cited as obstacles to flying wing passenger service, along with the egress and other safety issues. It's tempting to say: "This has been done before", but these people are far too smart to be dismissed out of hand like that. I am sure there is some really innovative ideas in there. I can't wait to see this.


There are 10 kinds of people in the world; those who understand binary, and those that don't.
35 replies: All unread, showing first 25:
 
User currently offlineBobster2 From , joined Dec 1969, posts, RR:
Reply 1, posted (7 years 8 months 4 weeks 1 day 18 hours ago) and read 4525 times:

I couldn't wait until tomorrow.  Smile So I found their web site and it has a flyer with pictures. They look very similar to what we've already seen from the Nasa and Boeing research.

http://www.cambridge-mit.org/research/sai

flyer: http://asp2.miuk.com/cmilive/documents/SAI_flyer_2006.pdf


User currently offline3201 From , joined Dec 1969, posts, RR:
Reply 2, posted (7 years 8 months 4 weeks 1 day 17 hours ago) and read 4509 times:

Quoting Bobster2 (Reply 1):
So I found their web site and it has a flyer with pictures. They look very similar to what we've already seen from the Nasa and Boeing research.

No surprise there -- they're certainly well aware of all the prevous work and some of the same people are involved (for example, Karen Wilcox, who works on this stuff at MIT, has done BWB research with Sean Wakayama of Boeing-Long Beach, who did a lot of the BWB stuff there and before that was in the group at Stanford that worked with NASA and Douglas early on in the BWB program and built the first two generations of flying models for control system design).


User currently offlineLehpron From United States of America, joined Jul 2001, 7028 posts, RR: 21
Reply 3, posted (7 years 8 months 4 weeks 1 day 10 hours ago) and read 4450 times:

Quoting Bobster2 (Reply 1):
They look very similar to what we've already seen from the Nasa and Boeing research.

There is a difference between looking similar, being similar, and being the same thing. To many, that concept is just another BWB and while may facinate people, there are those (idiots IMO) who figure if it is not immediately successful, why build it?

I'd rather judge aircraft by definition rather than image, I don't care what they look like.

Still, does anyone find that concept's cabin appear small with respect to the overall scale? I know it is my perception and it is probably the camera angle (in CAD renderings there are camera angles, I know its not a photo).



The meaning of life is curiosity; we were put on this planet to explore opportunities.
User currently offlineDarkBlue From United States of America, joined Sep 2003, 233 posts, RR: 10
Reply 4, posted (7 years 8 months 4 weeks 1 day 7 hours ago) and read 4401 times:

Reading through the flyer made me curious on a couple things:

"Ingesting: some of the aircraft boundary
layer flow is ingested into the engines,
increasing propulsive efficiency and reducing
fuel burn."


I'm interested to read more on this. Ingesting boundary layer air is generally not a good thing. I wonder what analysis they have done that shows that pulling in "dirty" air improves propulsive efficiency.


"Multiple-Fan Geared Engine Configuration: three cores and nine fans are
easier to embed in airframe, reduce weight and nacelle drag, enhance
boundary layer ingestion, and the low fan tip speeds lead to low noise"


This multiple geared-fan configuration is interesting, although I didn't see any turbine to drive the fans. The cross section diagram shows a single stage HP turbine to drive a 4 stage axial compressor plus a centrigul compressor. This is followed by a 3 stage IP turbine that appears to drive a traditional 9 stage compressor. To drive that huge 20 BPR, 3-spool fan you would need an enormous LP turbine. I sure hope they don't expect the little 3 stage turbine to able to do this in addition to the compressor that it's already powering.


User currently offline2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 60
Reply 5, posted (7 years 8 months 4 weeks 1 day 6 hours ago) and read 4397 times:
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This image isn't specific to the article, but I thought it would be worth sharing:





2H4





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User currently offlineYYZSaabGuy From Canada, joined Jun 2006, 25 posts, RR: 0
Reply 6, posted (7 years 8 months 4 weeks 1 day 6 hours ago) and read 4395 times:

Interesting proposal. Wonder how they plan to protect against the damage associated with a catastrophic engine failure - having the engines below-wing and away from the fuselage solves that problem more effectively, I would've thought, than having the engines embedded in the wing. How have the British rationalized this issue in, for example, their "V" series aircraft?

User currently offline2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 60
Reply 7, posted (7 years 8 months 4 weeks 1 day 6 hours ago) and read 4392 times:
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Quoting YYZSaabGuy (Reply 6):
Wonder how they plan to protect against the damage associated with a catastrophic engine failure

I wonder about the measures taken by the V-bomber engineers, as well. As for modern solutions, though, Kevlar-style materials have come a very long way in the past few decades. Somehow, I don't think it will be very difficult to find a suitably light weight material to reliably contain engine debris.



2H4





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User currently offlineYYZSaabGuy From Canada, joined Jun 2006, 25 posts, RR: 0
Reply 8, posted (7 years 8 months 4 weeks 1 day 5 hours ago) and read 4379 times:

Quoting 2H4 (Reply 7):
As for modern solutions, though, Kevlar-style materials have come a very long way in the past few decades. Somehow, I don't think it will be very difficult to find a suitably light weight material to reliably contain engine debris.

It would be informativeto calculate the mass/momentum behind a fan blade spinning at several thousand RPM vs. that associated with a .45 round, then compare both against Kevlar-type materials. Somehow, looking at the damage on that Emirates engine cowling from last week, I'm not as optimistic. Having said which, here's hoping you're correct: those are some great-looking designs!


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17003 posts, RR: 67
Reply 9, posted (7 years 8 months 4 weeks 1 day 4 hours ago) and read 4366 times:

Good pic here: http://www.aftonbladet.se/vss/rss/story/0,2789,925332,00.html


My favorite quote from http://www.cnn.com/2006/TECH/11/06/silent.aircraft.ap/index.html

The design, to be announced in a news conference at the Royal Aeronautical Society in London, would blend fuselage and wings together so that the entire airframe provides lift -- an approach that to date has been confined largely to payload-carrying military aircraft such as long-range bombers.

Because as we all know, airliners don't carry payload.

[Edited 2006-11-06 18:22:54]


"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineBobster2 From , joined Dec 1969, posts, RR:
Reply 10, posted (7 years 8 months 4 weeks 1 day 2 hours ago) and read 4340 times:

Here it is, unveiled:



User currently offlineLemurs From United States of America, joined Mar 2005, 1439 posts, RR: 4
Reply 11, posted (7 years 8 months 4 weeks 1 day 2 hours ago) and read 4335 times:

Quoting Starlionblue (Reply 9):
Because as we all know, airliners don't carry payload.

Bombs and cruise missles don't get sick or care if there aren't many windows nearby, though.  Wink



There are 10 kinds of people in the world; those who understand binary, and those that don't.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17003 posts, RR: 67
Reply 12, posted (7 years 8 months 4 weeks 1 day 2 hours ago) and read 4330 times:

Quoting Lemurs (Reply 11):
Bombs and cruise missles don't get sick or care if there aren't many windows nearby, though.

Very true. But I bet for REALLY low fares you could pack your average Joe Public in without windows too.  Wink



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineBobster2 From , joined Dec 1969, posts, RR:
Reply 13, posted (7 years 8 months 4 weeks 1 day 2 hours ago) and read 4326 times:

Another view:



User currently offline3201 From , joined Dec 1969, posts, RR:
Reply 14, posted (7 years 8 months 4 weeks 1 day 1 hour ago) and read 4313 times:

Quoting DarkBlue (Reply 4):
Ingesting boundary layer air is generally not a good thing. I wonder what analysis they have done that shows that pulling in "dirty" air improves propulsive efficiency.

This has been a specific research topic for a while -- here's one example:

http://www.desktopaero.com/Publications/AIAA-2002-5665.pdf

Ingesting the BL is worth doing because even though the propulsive efficiency goes down, the aerodynamic efficiency goes up enough to make up for it. This is one of those ideas that only makes sense when you look at the whole big picture instead of isolating individual systems.

[Edited 2006-11-06 21:06:07]

User currently offline787atPAE From United States of America, joined Oct 2006, 143 posts, RR: 4
Reply 15, posted (7 years 8 months 4 weeks 17 hours ago) and read 4254 times:

Quoting 3201 (Reply 14):
Ingesting the BL is worth doing because even though the propulsive efficiency goes down, the aerodynamic efficiency goes up enough to make up for it. This is one of those ideas that only makes sense when you look at the whole big picture instead of isolating individual systems.

This is an interesting coincedence. My lead engineer was telling the folks in my aisle today about a Boeing vs McD competetion before the C-17 came about. It was supposed to be a replacement for the C-130. The Boeing version had jet engines on top that blew over the wings and flaps, thereby creating an even lower pressure than normal.

Anybody have any more info on this?


User currently offline2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 60
Reply 16, posted (7 years 8 months 4 weeks 17 hours ago) and read 4251 times:
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Quoting 787atPAE (Reply 15):
Anybody have any more info on this?

Of course....this is Tech/Ops!

Boeing YC-14:


View Large View Medium
Click here for bigger photo!

Photo © Martin Stephen
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Photo © Mick Bajcar



http://www.answers.com/topic/boeing-yc-14





McDonnell-Douglas YC-15:


View Large View Medium
Click here for bigger photo!

Photo © Steve Brimley
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Click here for bigger photo!

Photo © Martin Pole



http://www.answers.com/topic/mcdonnell-douglas-yc-15


Welcome to the forums, 787....great to have you aboard!



2H4





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User currently offlineFuturecaptain From , joined Dec 1969, posts, RR:
Reply 17, posted (7 years 8 months 4 weeks 15 hours ago) and read 4238 times:

Now, blended wing a/c are nothing new and the clastrophobia issue has been discussed before.

Now, one thing that has got me thinking. Does anyone have any theoretical cabin data on these a/c? To me it seems the a/c gets very wide as you go back, appears significantly wider than a commercial airliner flying today. Now, my question is if the worst should happen, God forbid, and one of these goes down how much of a walk will the people in the back have to get to an emergency exit? It seems to me the people in the last row, middle seats will have quite a distance to travel to get out.

Also, no rudder? Now, I'm not ignorant and realize planes can fly without one, but they are a very good way to control yaw. What devices will be added, if any, to help with the natural yawing motions of a/c?


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17003 posts, RR: 67
Reply 18, posted (7 years 8 months 4 weeks 8 hours ago) and read 4204 times:

Quoting Futurecaptain (Reply 17):
Now, one thing that has got me thinking. Does anyone have any theoretical cabin data on these a/c? To me it seems the a/c gets very wide as you go back, appears significantly wider than a commercial airliner flying today. Now, my question is if the worst should happen, God forbid, and one of these goes down how much of a walk will the people in the back have to get to an emergency exit? It seems to me the people in the last row, middle seats will have quite a distance to travel to get out.

That's why they call them the cheap seats.  Wink Seriously though, would the distance to an exit really be more than those sitting far from an exit in today's tube + wings?

Quoting Futurecaptain (Reply 17):
Also, no rudder? Now, I'm not ignorant and realize planes can fly without one, but they are a very good way to control yaw. What devices will be added, if any, to help with the natural yawing motions of a/c?

Differential thrust and split ailerons come to mind. But I don't know about their relative efficiency.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offline2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 60
Reply 19, posted (7 years 8 months 4 weeks 7 hours ago) and read 4189 times:
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Quoting Starlionblue (Reply 18):
Seriously though, would the distance to an exit really be more than those sitting far from an exit in today's tube + wings?

Maybe not to the nearest exit, but don't aircraft have to be certified for an evacuation using only the doors on one side? If that's the case, I would imagine it would be a very long way to the opposite side emergency exits...



2H4





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User currently offlineVikkyvik From United States of America, joined exactly 11 years ago today! , 9805 posts, RR: 26
Reply 20, posted (7 years 8 months 4 weeks 6 hours ago) and read 4181 times:
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Quoting 2H4 (Reply 19):
Maybe not to the nearest exit, but don't aircraft have to be certified for an evacuation using only the doors on one side?

Believe it's with half the doors unusable, where the test passengers don't know which doors will be unusable.

Quoting Futurecaptain (Reply 17):
Also, no rudder? Now, I'm not ignorant and realize planes can fly without one, but they are a very good way to control yaw. What devices will be added, if any, to help with the natural yawing motions of a/c?

Well the A/C does have two rather large winglets, which would provide some yaw stability, and maybe some control if there were control surfaces mounted in them.

I also wonder what the longitudinal stability would be like on that thing. Looks like it could be a nightmare, but who knows.



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offlineAerogeek From United States of America, joined Jun 2006, 10 posts, RR: 0
Reply 21, posted (7 years 8 months 4 weeks 6 hours ago) and read 4179 times:

Quoting Starlionblue (Reply 18):
Also, no rudder? Now, I'm not ignorant and realize planes can fly without one, but they are a very good way to control yaw. What devices will be added, if any, to help with the natural yawing motions of a/c?

If it's anything like the BWB concept, the vertical fins/winglets would provide some static directional stability, and stability augmentation would do the rest via the ailerons. The BWB flight control system also helped with static pitch stability and various dynamic modes. Lots of closed-loop control.


User currently offline113312 From United States of America, joined Apr 2005, 569 posts, RR: 1
Reply 22, posted (7 years 8 months 4 weeks 6 hours ago) and read 4177 times:

The devil is always in the details. There are big risks by embedding the engines within the body of the plane. This has not been done since the Comet and the TU-104. Also, consider the noise and vibration of the machinery to drive additional fans from each engine as is shown in their expanded diagram.

User currently offlineStarlionblue From Greenland, joined Feb 2004, 17003 posts, RR: 67
Reply 23, posted (7 years 8 months 4 weeks 5 hours ago) and read 4167 times:

Quoting Aerogeek (Reply 21):
Quoting Starlionblue (Reply 18):
Also, no rudder? Now, I'm not ignorant and realize planes can fly without one, but they are a very good way to control yaw. What devices will be added, if any, to help with the natural yawing motions of a/c?

If it's anything like the BWB concept, the vertical fins/winglets would provide some static directional stability, and stability augmentation would do the rest via the ailerons. The BWB flight control system also helped with static pitch stability and various dynamic modes. Lots of closed-loop control.

Nice. But note you misquoted.  Wink



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineAerogeek From United States of America, joined Jun 2006, 10 posts, RR: 0
Reply 24, posted (7 years 8 months 4 weeks 3 hours ago) and read 4144 times:

Quoting Starlionblue (Reply 23):
Nice. But note you misquoted.

Oops, my mistake. Meant to quote Futurecaptain. Noted.


25 Post contains links Futurecaptain : I was looking into this. According to http://www.twitt.org/bldwing.htm they specifically state an a/c of this design could potentially be large enoug
26 Post contains images Bobster2 : Forget about emergency exits. How would they even get to the bathroom? Imagine 5-5-5-5-5-5-5-5-5-5 seating, and that would be first class. They would
27 Post contains images Futurecaptain : Ryanair would have 25-25 seating.
28 Post contains images 787atPAE : Does the configuration/structure of the aircraft really matter anymore? Ignoring certain factors, I would say no. Fly-by-wire flight control systems
29 Post contains images Starlionblue : Quite right. However you still have to consider the G forces felt by "outboard" pax. Not that we are talking air combat maneuvers, but imagine what w
30 Blackbird : To be absolutely honest. The big problems I remember hearing about BWB-aircaft is structural integrity at a reasonable weight. Regarding the claustrop
31 Starlionblue : Indeed. Like it or not, cylinders and almost cylinders like the current tubes with wings are great pressure vessels. Very low weight for the strength
32 David L : I take your point but wouldn't it be a better test to force high pressure air into the structure since that's the more usual scenario? It can't be ea
33 Starlionblue : I agree. Brainfart. But this doesn't really change the situation.
34 Post contains images David L : Agreed. If you try to inflate something, it'll try to from a sphere or cylinder so starting out with a cylinder gets you there with less bending.
35 Starlionblue : Lol!
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