backtop

Print 43 comment(s) - last by DennisB.. on Aug 9 at 2:13 PM
First scale model flies without incident

Boeing has announced that its modified blended wing body research aircraft, designated the X-48C, flew for the first time yesterday at the NASA Dryden Flight Research Center.
 
The X-48C is a remotely piloted scale model of a heavy-lift subsonic vehicle that doesn't use conventional tube and wing airplane design. The maiden flight of the scale model was conducted at 7:56 AM Pacific daylight Time on August 7. The test aircraft flew to an altitude of 5500 feet and landed 9 minutes after takeoff.
 
"Working with NASA, we are very pleased to enter into the next flight-test phase of our work to explore and validate the aerodynamic characteristics and efficiencies of the Blended Wing Body concept," said Bob Liebeck, a Boeing Senior Technical Fellow and the company's BWB program manager.

 
"In our earlier flight testing of the X-48B, we proved that a BWB aircraft can be controlled as effectively as a conventional tube-and-wing aircraft during takeoffs and landings and other low-speed segments of the flight regime," Liebeck said. "With the X-48C, we will be evaluating the impact of noise shielding concepts on low-speed flight characteristics."
 
The Boeing X-48C is a modified version of the company's X-48B aircraft that flew 92 times at Dryden between 2007 and 2010. The C version has a pair of 89-pound thrust turbojet engines instead of the three 50-pound thrust engines on the previous B model. The C model also has been wingtip winglets that have been relocated inboard next the engines turning them into twin tail fins in effect. Boeing also extended the aft deck of the C by 2 feet at the rear.

 
The X-48C scale model that was flown has a 21-foot wingspan and weighs 500 pounds. It is an 8.5% scale model of a heavy lift aircraft that would have the 240-foot wingspan and could be developed in the next 15 to 20 years for military applications including aerial refueling and cargo delivery.
 
The scale test aircraft has an estimated top speed of 140 miles an hour and a maximum altitude of 10,000 feet.

Source: Boeing


Comments     Threshold


This article is over a month old, voting and posting comments is disabled
Clarity for Discussion
By Reclaimer77 on 8/8/2012 9:59:47 AM , Rating: 3
I could Google this stuff but I feel like having a convo about this. Boeing designed and built the B-2 Spirit stealth bomber, a blended wing aircraft and one of my personal favorites.

So my question I guess would be, what more are they hoping to learn about it from this prototype that they didn't already know moving forward from the B-2?




RE: Clarity for Discussion
By jeffkro on 8/8/2012 10:03:03 AM , Rating: 2
I think they must be more serious about trying to actually getting one into production. The future of commercial aviation is going to be all about efficiency, not speed


RE: Clarity for Discussion
By Chernobyl68 on 8/8/2012 2:04:47 PM , Rating: 2
The X-48 is a program Boeing inherited from McDonnell Douglas during the merger. Initial mockups of the passenger cabin were not very favorable to test groups, and as mentioned below there are logistical challenges on evacuations. Still, the inherent fuel efficiencies make this a great idea for civil aviation if it can overcome those obstacles. A freighter design that is successful for a number of years may spur the airlines to "make it work" somehow for passenger service.


RE: Clarity for Discussion
By whitt107 on 8/8/2012 3:34:13 PM , Rating: 2
I wonder if there might be multiple uses for this: A prototype model of a full scale military aircraft (as stated), then maybe as a drone, and then even civilian usage.

So going back on a previous worked on design may be for multiple good reasons.


RE: Clarity for Discussion
By Reclaimer77 on 8/8/2012 10:05:13 AM , Rating: 2
Correction: Boeing worked with Northrop on the B-2 and built a lot of the wing and other components. It was a design team collaboration.


RE: Clarity for Discussion
By kattanna on 8/8/2012 10:57:50 AM , Rating: 3
the B2 was a pure flying wing.

this aircraft has more of a flat body design with wings. its like halfway between a regular aircraft and the B2


RE: Clarity for Discussion
By drycrust3 on 8/8/2012 11:41:18 AM , Rating: 4
Here is a link for an F15 that lost a whole wing in a practice dog fight and still managed to land safely because of the lift from the body.
http://www.liveleak.com/view?i=b5a79a516c


RE: Clarity for Discussion
By kattanna on 8/8/2012 11:49:51 AM , Rating: 3
now thats one awesome pilot right there!


RE: Clarity for Discussion
By BZDTemp on 8/8/2012 12:41:51 PM , Rating: 2
Crazy. Great piece of flying (except for the crashing into another aircraft of course).

Disregarding the F15 bit and instead on the TV show. The TV show people should be ashamed for trying to drama up something like this with lousy stock footage (some also used in Top Gun).


RE: Clarity for Discussion
By Reclaimer77 on 8/8/2012 3:52:53 PM , Rating: 2
Awesome story.

Btw Top Gun is one of my favorite guilty pleasure movies, seen it like 100 times. I'm pretty confident no footage used in this clip was from the movie.

But just wow, I mean jet fuel is pouring out of what is left of the wing, he's spinning out of control, and he hits the burners!? He's lucky he didn't explode that instant! Most pilots wouldn't have dared go into full burner after having a mid-air and unknown damage, but it saved his ass because the speed gave him enough lift.

Just incredible. I thought the A-10 was the only thing in our inventory that could be flown back home with that kind of damage.


RE: Clarity for Discussion
By Apone on 8/8/2012 12:27:14 PM , Rating: 1
Good question and I have a couple theories based on the article information. Considering the B-2 is a multi-billion dollar aircraft, perhaps Boeing is attempting to extract the benefits and efficiencies from the B-2’s design and engineering and are applying it a smaller concept (and more cost-effective) like the widely adopted UAV platform. Or perhaps Boeing has examined the B-2’s current design and along with other researched wing designs, are experimenting with new conceptualized wing/engine/tail configurations in an attempt to further push the envelope of aerospace engineering innovation.


RE: Clarity for Discussion
By Fritzr on 8/8/2012 1:54:43 PM , Rating: 2
Boeing and the other major R&D outfits have been working on flying wing designs from at least the 1930s. The big problem has always been stability.

This blended wing is a departure from classic designs in that it adds a conventional tail assembly to a flying wing.

You get the lifting body advantages of the pure wing design and the stability of the wing&tail designs. With a very deep wing chord you can put cargo space in most of the wing volume.

As another commenter noted, this can be problem with passenger aircraft regulations, but is an idea that was proposed for a luxury airliner in the 1930s. The huge volume allows for seating, lounges, dining room and galley and other Premium First Class amenities that are seen in limited form on A380s and 747s.


RE: Clarity for Discussion
By fic2 on 8/8/2012 3:52:01 PM , Rating: 2
In today's version of commercial aircraft it would more than likely just allow the airline to cram more people per jet. At least for U.S. airlines.


RE: Clarity for Discussion
By 91TTZ on 8/8/2012 3:53:18 PM , Rating: 2
The B-2 isn't a multi-billion dollar aircraft. It cost about $740 million in 1997. Compare that to a 747 which cost about $300 million at the time.

The inflated cost that you often hear is the amortized cost which includes spares, maintenance, tooling, and the R&D to design it. Since it was a long, giant program and they ended up cutting the number ordered to 21, the per unit cost was very high.

If you were to calculate the cost of this X-48C model using the same method you'd probably find that it cost tens of millions of dollars.


RE: Clarity for Discussion
By Chernobyl68 on 8/8/2012 1:18:44 PM , Rating: 2
No, Northrop Grumman designed and built the B-2.


RE: Clarity for Discussion
By DennisB on 8/8/2012 1:36:14 PM , Rating: 2
The B2 was designed for stealth and had little choice on the shape of the wing. Efficiency happens to be a bonus.
Also it's not stable.
This new design is a body wing design, and designed to the best possible theory we got now. May not be perfect or there may be better theories in the future who knows. This one is more of a glider.

That F-15 has long become history, was one of the first F15 in combat. There aren't many fighters with lifting bodies, though: F11,F14,F15,F22,Mig29,Su27 etc. Stability is not desired in a modern fighter.


RE: Clarity for Discussion
By JediJeb on 8/8/2012 3:47:49 PM , Rating: 2
The predecessor to the B2 was the XP-35/YB-35 from Northrop, which first flew in the 40s I believe. I remember a story of how Northrop developed those and all the controversy on the cancellation of the orders from the Air Force. Northrop had plans to even offer it in a passenger configuration and showed mockups of how it would look in newsreel footage. I think they even had plans for a large windowed area in either the forward or rearward area as sort of a sky view lounge.

It is a shame how politics often ruins what could be great progress.


RE: Clarity for Discussion
By yomamafor1 on 8/9/2012 12:10:06 AM , Rating: 2
Perhaps external engine pods on a blended wing design? Or how to reduce the number of computers needed to control the aircraft? Or the potential usage in commercial airline industry (which was the original intention of X-48)? Or increase safety and flight envelope of the aircraft so it can be safely used in commercial airline?

Just because X-48 and B-2 look similar, doesn't mean they are identical in flight performance and mission profiles.


RE: Clarity for Discussion
By Amiga500 on 8/9/2012 4:49:24 AM , Rating: 2
The B2 is a flying wing (with the aerodynamics and control no doubt completely designed by Northrop who have a long history in flying wings - such as the YB-49).

These are blended wing bodies - with a significant fuselage extension ahead of the wing 1/4 chord line (the usual approx. position of the local aerofoil centre of pressure - in simple terms where lift force would 'be'). So there will be significant changes in aircraft balance from that alone.

Additionally, the presence of the fuselage protrusion will lead to changes in the aircraft centre of pressure position as angle of attack changes. [This does occur to a small degree to the wing-body of existing aircraft, but its a relatively small change.]

With your control surfaces having relatively small lever arms (no big tail extension) - ensuring sufficient control authority over the whole flight range is always going to be an issue.

Hence the test program with what looks like a very small change from a B2. But it is very necessary.


RE: Clarity for Discussion
By Amiga500 on 8/9/2012 4:53:30 AM , Rating: 2
Oh and note also the position of the engines relative to the B2. The B2's engines thrust vector would be acting largely through the aircraft's centre of gravity.

The BWBs engines are significantly above the c.g. so will be inducing nose down pitching moments.

Its yet another little change that needs to be evaluated... they all add up.


RE: Clarity for Discussion
By DennisB on 8/9/2012 5:36:20 AM , Rating: 2
quote:
The B2 is a flying wing (with the aerodynamics and control no doubt completely designed by Northrop who have a long history in flying wings - such as the YB-49).

Which in turn was based on nazi stuff as so many others
http://untoldvalor.blogspot.com/2009/07/did-german...

For some reason it's mostly either nazi or russian based...but we perfect them.


RE: Clarity for Discussion
By Amiga500 on 8/9/2012 6:04:12 AM , Rating: 2
No, no.

In this instance that is unfair.

The Horten flying wing flew in late WW2 (1944 I think). While the YB-35 flew in 1946, it was a response to an RFP issued in 1941.

Yes, you are right, there are many examples of work being directly lifted from Germans aerodynamicists such as Lippisch - but this is not one of them.


RE: Clarity for Discussion
By Norseman4 on 8/9/2012 7:47:45 AM , Rating: 2
Considering that Jack Northrop had been developing flying wing concepts since the late '20s, culminating in the N-1M which flew in July 1940, and the Horton Flying Wing (which you linked to) never got beyond the blueprints, I'd say bupkis.

True, he did use publicly available international aeronautical engineering knowledge and had assistance from many U.S. engineers of Germanic descent. To say the U.S. that Northrop based his flight controls of of Nazi mechanics, however, is just wrong.

http://www.century-of-flight.net/Aviation%20histor...
http://www.dailymail.co.uk/news/article-1198112/Sl...


RE: Clarity for Discussion
By Amiga500 on 8/9/2012 9:31:40 AM , Rating: 2
The 229 flew, albeit in prototype form only. :-)


RE: Clarity for Discussion
By DennisB on 8/9/2012 2:13:37 PM , Rating: 2
Yes, it was the last Horton design. But others flew and were exclusive one wing designs. It may be debatable but all remaining Hortons are all in the us.


Regulations Nightmare
By Voldenuit on 8/8/2012 11:58:27 AM , Rating: 2
It's going to be a nightmare to certify this aircraft to civil aircraft regulations, especially emergency evacuation requirements.

FAR 23.803 states:
"For airplanes having a seating capacity of more than 44 passengers, it must be shown that the maximum seating capacity, including the number of crewmembers required by the operating rules for which certification is requested, can be evacuated from the airplane to the ground under simulated emergency conditions within 90 seconds."

Imagine evacuating 1,000+ people (A380 already holds ~800+ passengers, so this figure is entirely plausible) in under 90 seconds. Now imagine that 2/3 of those people are in the central fuselage area and they have to make their way to the extremities of the aircraft to reach the escape hatches. You can't use underbody escape exits because of water landings and potential landing gear collapse, so the only options are side exits and possibly roof exits - but then you'd still have to contend with passengers who have limited mobility (elderly, small children, wheelchair bound) and the difficulty of clearing them away from the body of the aircraft in that time frame.

Currently, most airline operators make more money from cargo/freight than passengers, so I could see a scenario where the central fuselage area is used exclusively for cargo, but this will limit the routes that a BWB craft is profitable on.

Great idea, but lots of kinks will need to be worked out.




RE: Regulations Nightmare
By Voldenuit on 8/8/2012 11:59:36 AM , Rating: 2
Typo, FAR 25.803 not, 23.


RE: Regulations Nightmare
By Fritzr on 8/8/2012 1:43:53 PM , Rating: 2
I don't see that as an obstacle in certifying these designs as heavy lift civil cargo.

Agreed though, that a lot of thought will need to go into evacuation exits for a pure passenger configuration.


RE: Regulations Nightmare
By Chernobyl68 on 8/8/2012 2:08:36 PM , Rating: 2
It might be that you simply need more exits above the wings in order to reduce the distance for passengers to travel to their exit. They'd be walking more laterally then longitudinally.You'd need greater row spacing, and people would certainly enjoy the greater legroom.


RE: Regulations Nightmare
By Ringold on 8/8/2012 12:54:38 PM , Rating: 2
Excellent point, once we start talking about a sufficiently large aircraft. I suppose they could modify the FAR's, or like you said, place limitations on it. UPS, FedEx, DHL et al might love it though.


RE: Regulations Nightmare
By zephyrprime on 8/8/2012 2:31:34 PM , Rating: 2
I don't think it would be as bad as you think. A typical tube airplane could have 2 emergency exits, one in the front and one in the back (if the plane is big enough to warrant 2). The exits don't come out of both sides because the plane is so narrow, there is no point to having exits on both sides. With a widebody plane like this, you could have 4 escape routes, one on each corner of the "square" of the plane's body. Also, the seating plan is more 2 dimensional than the quasi 1 dimensional seating plan of a conventional tube aircraft. For the same capacity, the distance from the middle to the nearest exit would be smaller with a 2d seating plan than for a 1d seating plan.


RE: Regulations Nightmare
By Keeir on 8/8/2012 4:50:54 PM , Rating: 2
Errrr... you really don't understand.

This type of aircraft would need to seat hundreds of people. (Consider that the hieght of the Fuselage needs to be ~8' mininum to allow for system and people standing up. It appears to me that 5 times the width as the hieght leading to a minimum passenger space of ~700". Given a generous 20" seat width, even 700" is enough for -25- seats across. Probably even more seats could be jammed in. Given ~20+ rows of length, thats 600+ people.

In comparison, the A380 seats ~650. It has -14- emergency exits

http://aviation-safety.net/airlinesafety/exits/exi...

Spread evenly along its length. This givens a Person/Exit ratio of ~60.

On this concept, there aren't very many surfaces that are good for water landing. Pretty much the entire area aft of the windows will need to be a door to provide the space adequate enough to allow exit.

Again, for each "person" sized opening, its hard to see how your going to get much more than 1 person per second through that opening. I have trouble seeing the 10-20 person sized emerency exits above the water line (wing line).


RE: Regulations Nightmare
By Amiga500 on 8/9/2012 5:02:28 AM , Rating: 2
There may be a couple of ways.

Sub-compartments for the passengers. The bounds for those compartments will be structural members that reinforce the pressure vessel (which may be needed anyway). Staircases to emergency (literally) overwing exits can then be located in these areas. OK, so some internal volume is 'wasted' on the staircases - but if its a design enabler...

The second option is to sacrifice some of the blending and have multiple decks that do not extend for the same width i.e. (ignore the *)

******_
****_/*\_
___/_____\___

So you can evac laterally from both decks. Bottom deck evac might still be an issue.


RE: Regulations Nightmare
By Voldenuit on 8/8/2012 4:55:57 PM , Rating: 2
The Boeing 777 and 787 already have 8 emergency exits each. A 747 has 10. Even the tiny 737 has 6.

When Airbus was conducting emergency evacuation drills on the A380 to meet certification requirements, they barely made the 90-second cutoff, and several people were injured (including at least one fracture) in the demonstration. Another point the A380 test brought up was what would happen if one side of the aircraft were inaccessible. In the test, EASA disabled half of the 16 exits on the plane. In real life, this might happen if one side were buried in a ditch, a building, on fire, or hanging off a precipice. Translate that to a BWB with a huge passenger to cross-sectional area ratio, and you have an even bigger problem.

Evacuating passengers from a wide body airplane is a non-trivial exercise, both in reality and to meet certification requirements. Unfortunately, there's not an easy workaround.


RE: Regulations Nightmare
By Natch on 8/8/2012 2:56:15 PM , Rating: 2
Yeah, you wouldn't want a scene like this happening!
http://www.youtube.com/watch?v=eNOpFyPvx2I

Not sure how long it took them to evacuate the jet that did the emergency landing in the Hudson River, but I'd bet it was over 90 seconds. Ridiculously short amount of time, IMHO.


rc pilot
By jeffkro on 8/8/2012 9:59:49 AM , Rating: 2
Man as an rc plane enthusiast I would love to get my hands on that. I wonder how many volunteers they get to fly it, much cooler than computer simulations.




RE: rc pilot
By Flunk on 8/8/2012 10:09:15 AM , Rating: 2
My guess is that it's either computer controlled or rigged up like one of those drone aircraft that only needs one pilot part of the time.


RE: rc pilot
By zephyrprime on 8/8/2012 11:41:09 AM , Rating: 2
Probably manually flown by remote control.


RE: rc pilot
By WalksTheWalk on 8/8/2012 12:15:39 PM , Rating: 2
Probably not this kind of remote either;

http://www.hobby-lobby.com/dx5e_5_channel_transmit...


RE: rc pilot
By jeffkro on 8/8/2012 9:32:30 PM , Rating: 2
I could fly it with that. :)


efficiency
By zephyrprime on 8/8/2012 11:42:12 AM , Rating: 2
By the way, the motivation for a craft like this is efficiency. It uses the fuselage for lift surface more than a conventional plane does. Also, mounting the engines on top reduces noise on the ground.




UFO's
By macca007 on 8/9/2012 3:30:31 AM , Rating: 2
AHHHHHH so these are the triangle UFO's people are seeing lately? wink wink ;)

P.S.
(yes it's a joke) for those a little lacking in between the ears!




Artist's conception
By Chernobyl68 on 8/9/2012 1:52:54 PM , Rating: 2
I remember this image from an old popular science, or popular mechanics article.

http://www.flightglobal.com/blogs/aircraft-picture...




"A lot of people pay zero for the cellphone ... That's what it's worth." -- Apple Chief Operating Officer Timothy Cook









botimage
Copyright 2013 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki