> "we’re looking into new options to having a rest or taking meals on a plane. Offering food from a buffet is one of the options we’re sinking our teeth in"
Based on the A380 "promises" of in-flight gyms/casino/salons/creches, I think we can safely call bullshit on this - we'll just get more seats crammed in as usual (in economy at least - perhaps first class will get these?). That is fine - I understand the economics - it is marketing I guess.
You get what you pay for. If you want to pay absolute bottom-dollar prices, you're going to get absolute bottom-dollar service. If you want to pay more you can and will get more services. I've hung out at an on-board bar on a 777 in the last year on a flight from Australia to the US, but the ticket cost over $8k USD round-trip.
It's possible to have a private shower and bedroom onboard an A380 flight, but you will pay dearly for the privilege.
There's room in the market for both extremes as well as in the middle. I doubt you'll get a buffet service on a round trip ticket that costs <$500 (trans-oceanic, at least) as it likely is not economical to offer that. That being said, there are airlines that are offering improved options even in Economy cabins... they just charge for it. An example is Air New Zealand's "Economy Skycouch" https://www.airnewzealand.com/economy-skycouch
So with the possibility that this design could save on fuel costs, maybe airlines will be able to sell upgraded experiences at prices that are today bare-bones. Time will tell.
The problem is that now there's so much price pressure on the economy seats, they are subsidized by the more expensive options. If you want a first class seat today, that takes 50% more room on the aircraft, you will pay what, 2, 3, 4 times as much money? There's really no middle ground. I'm fine with that, cause I have a family or four, we're all short, and I'm cheap, but I guess that makes me part of the problem. :D
First class seats take up way more space than 50% more. Look at the seat maps on something like SeatGuru. On width alone they take up over twice the space, and I'd guess depth would be far more.
Although in my experience, many companies that don't care that much about travel expenses pay most of the economy seats. At least on the transatlantic flights I've been on.
Most longer intercontinental flights have both business and first in my experience. But I agree that I don't think I've seen it on a narrow body airplane
Yeah that's just not true at all in the US. Delta's premium economy gives an extra inch or so. Sometimes you can get lucky in finding one of the few seats with no person in front of you. But those go fast, and usually to people who don't even need them(not that there is a problem of need, but as a fellow 6'5er it is a bit annoying). Even so, even on shorter hauls, that kind of upgrade is typically in the 100 dollar range.
Yes.
I don't fly too much, and I never saw these upgrades..unless they were quite expensive...and it is per flight, meaning, if there are several layovers, you pay for each plane.
Literally everything you said is false. It's $25-$35 or so in the US for 6"+ extra room. It's never been in the $100+ range in any flight I've ever been on.
Can you cite even a single source? I, unfortunately, fly all the time. Chicago to SFO upgrade on United is 129 dollars. And you don't get 6 inches more legroom...
Well, thanks for that. I'll admit I'm a bit surprised, and also spoke too broadly(aka, wrong...perhaps). I'm curious now what airline/route that's for. Even my direct 2 hour flights to DC cost 40 to 50 to upgrade at a minimum, the last one wanted 69 dollars...
Airlines have been having record profit the last several years, especially in the US. Over the last decade they have figured out how to take back pricing power from the internet and they've gotten better at data anlysis and price discrimination.
> It's possible to have a private shower and bedroom onboard an A380 flight, but you will pay dearly for the privilege.
I wonder if a paid shower pass system would work. You wait your turn, but you get to take a shower, for, say, something like $100. Just seems like it's kept to an all-or-nothing on purpose.
From my experience, flying longer connections actually makes the price lower. Significantly. For example 30% longer flight, half the normal price. So nobody really cares about fuel in pricing
500 years ago it took Columbus and his crew of 88 men ten weeks to reach America in three 58 foot, 100 ton wooden
boats pushed along the ocean by wind. They had no toilets, ate boiled food with cheese and salted meats.
Today, 525 of us can travel on a 230 feet long, 600 ton flying boat lifted above the clouds crossing over the north pole from Los Angeles to Dubai at Mach 0.8 in 17 hours. We can watch movies, special order a kosher or vegetarian meal, drink fine wine while wearing complimentary socks and PJ's. For a few thousand dollars each.
For a lot more in-depth info, and even flight footage from a scaled RC demonstrator, see link below (from 2015, flight test at 1:18:30 in the video - yes it's a >1h long presentation/lecture)
In case anyone else wondered why an A380 would include religious symbolism: in North American English, a crèche is a Christmas nativity scene with baby Jesus, while in British English, a crèche is a nursery/daycare. The latter makes much more sense on a plane.
Interesting - I assumed creche was an American term and widely understood. In the UK I've never heard it used much (we typically use "nursery" but I opted for creche based on the assumption that most readers are not UK-natives)
I agree with that. I’ve only known crèches as places where a human body is held in order to be augmented or have a mind transfer to a body in a second crèche.
Economy class seats generally speaking will earn the least amount of money to an airline, so this idea would actually likely be the most unprofitable option.
To make it truly profitable, you convert the plane to First class, but then you'll need to fill all those seats.
Why, then, do the companies only offering one class (South West, Ryan Air) tend to make a profit, while the ones with multi class (KLM, Air France, American Airlines) tend to lose money?
That video is very wrong compared to real life. For the first: it assumes a full plane. My experience is that economy tends to be full, business has a lot of available seats. For the second: it does not account for the cost of running lounges, fast track security and other complimentary services offered to business and first class passengers.
Look at the companies. Filling the plane with economy passengers and offering low service level is what brings profitability.
I believe Southwest makes its money by catering to business persons that pay more for flexible scheduling and more direct flight options rather than paying more for amenities.
The biggest issue with true flying wing aircraft is that they are aerodynamically unstable. They can't be flown by humans, and I don't know how well they do in unusual configuration, things like stalls, spins, spiral dives, ...
The rules are different for commercial aviation and for the military. The goal of commercial aviation is to get people to their destination, as safely and cheaply as possible, you don't have to fight against an enemy. As a result, commercial aviation is not very creative. They tend to use proven designs and incremental improvement.
Making a civilian flying wing aircraft will be a certification nightmare, which may involve several full-scale prototypes, a new kind of training for pilots, etc... It is a world where there is still a switch for the "no smoking" sign in the cockpit that doesn't do anything because all flights are non smoking now. Removing the button would require re-qualification and it is easier to leave it there.
The B737-MAX fiasco is another illustration. Just look at how far their went just to limit change...
I'm not saying that a flying wing commercial aircraft can't be done, but I have a feeling that the placement of passengers won't be the biggest issue.
That is not necessary true. A flying wing can be made completely stable.
The biggest issue with flying wings is for passengers experiencing much more up and down movements. Their position is (specially for the most backwards ones) more towards the wingtips. As you can understand a slight correction will move you a few meters up or down. Constantly.
One of the cited advantages is that the pressurized passenger tubes make the wing structure far more rigid to bending loads, because it has such a deep beam profile compared to a traditional wing. The observation of wing motion really reveals a disadvantage in traditional airplane structures.
The wing planform is passively stable without a tail, so there should be no issues related to certification as suggested upthread.
He does talk about gusts and stability in the video (around 34min in). Not the greatest communicator, but it does seem like they've put some thought into the concepts.
Stability in aeronautics is the tendency for an airplane to remain in equilibrium without control inputs. A helicopter is unstable, a Cessna is very stable. Comfort is a different metric. You can have a comfortable helicopter ride even though the aircraft is unstable. Comfort is also subjective, while stability is not.
To be clear: you are being downvoted because your grandparent comment specifically said "aerodynamically unstable". That's why everyone thinks it's so clear in context that your parent comment was referring to the technical, aeronautical meaning of "stable".
True, but we were specifically discussing aerodynamic stability and how it might affect safety, training, and regulation. The quality of the ride is a separate issue.
The flying wing would be a new "type" and therefore require a new type rating (special training on all the systems and performance) which is not super uncommon for new aircraft. As such it's not a big deal and any quirks would be covered by such training.
The 737 fiasco was almost entirely because they refuse to allow new 737 designs to require a new type rating and therefore force weird aircraft/cockpit designs that would otherwise seem stupid.
Also, commercial aircraft aren't really certified based on how they handle stalls, spins and spirals. Swept wings already handle those situations very badly and therefore systems are designed to prevent the aircraft from entering those parts of its flight envelope.
But it is. Militaries like to play the "protect our troops at all costs" card when it helps them, but ultimately they make decisions based on a nonzero amount of acceptable deaths.
Or alternately phrased - low performance is also a safety risk in the military context. Increasing accident death rate in exchange for reducing the enemy-action death rate can be a good tradeoff.
It’s fine in the sense that a fighter jet can glide for quite a while and even land without engines. If that’s not possible, the pilot can steer it to crash in a remote area and the pilot can escape.
A modern fighter jet is not a good glider. An F-16 can't fly without the computer. Have you tried to sit in the cockpit? The sticks don't even move, they are pressure sensitive only. You are right about the ejection, that's how the pilots survive a computer malfunction, with a complete hull loss as consequence.
There are very specific regulations relating to how transport category aircraft have to behave. One of these is the reason the 737 MAX has the specific MCAS behaviors that are probably responsible for two crashes: causing the aircraft to stall must require continually increasing the pitch-up control input (or something substantially similar), and that wasn't the case at low speed, high thrust, and high angle of attack.
It may be difficult to achieve the required flight characteristics without software augmentation in a flying wing, even if RC hobbyists can usually fly them manually without crashing. The 737 MAX has raised the question of whether it's a good idea to approve transport category aircraft that require help from software to have acceptable flight characteristics.
MCAS wasn't required for the MAX8 to fly it was required for it to maintain the common type rating with the existing 737 fleet. With training the MAX8 would have been fine to fly and pilots would have known to pitch down or decrease throttle when experiencing the engine induced pitching.
MCAS provides for the certification requirement of continually increasing stick forces with increasing pitch, which was otherwise not met at high angles of attack and high thrust settings.
MCAS (or another means to accomplish the same goal) was required for the aircraft to meet certification requirements, regardless of whether it was to share a common type rating with the rest of the 737 fleet (so long as it shared the landing gear with the rest of the 73' line, it was going to have this adverse aerodynamic raw result).
That regulation seems to be at a static thrust level right?
> 75 percent of maximum continuous power for reciprocating engines or the maximum power or thrust selected by the applicant as an operating limitation for use during climb for turbine engines; and
Wouldn't that give a stable pitch response because the thrust relative to the center of mass is constant? Also if the MCAS is always pushing the plane out of the given AoA (which seems to be what it's logic is, if AoA > x trim down until AoA < x) would that be considered outside the flight envelope anyways? The stick force curve goes screwy for every aircraft in a stall.
It's an aerodynamic issue with the 737 MAX: the engine cowlings themselves produce lift at a high angle of attack, and the engines are mounted farther forward than they are on other 737s.
Those aircraft, as far as I know would meet certification requirements without the software adding control inputs that are opposite to what the pilots command.
> RC flying wings are regularly flown by humans without any software in between the input and control surfaces.
Technically this is definitely not true. Any modern RC wing will use software to do elevon mixing and get elevator/aileron input into the actual mechanical surfaces. It's possible to do this mechanically but software is so much simpler it's a no brainer to just have a servo per surface and do everything else in software.
It may be true in the spirit of this discussion in the sense that most RC wings just do fixed software mappings between inputs and outputs instead of having an on-board computer taking into account attitude/airspeed/etc and adjusting the inputs based on this. That's what's actually needed for aerodynamically unstable aircraft and RC wings generally don't need that, although similar kinds of hardware do exist in the RC world and are used sometimes.
I mean, you could just as easily do the mixing on the TX side rather than the RX side. In that case, there is not software between the RX-servos and the control surfaces. I think that counts as 'no software between the input and control surfaces'.
The relevant question is whether there is an IMU providing feedback without which the plane would not fly.
It's my impression that "everybody" puts a flight controller between the servos and the receiver these days, either a sophisticated one running something like ArduPilot [1] or at least a cheap, dedicated flight stabilizer like (random pick) [2].
Maybe there is region differances here. Here in Sweden most RC-Wings, actually all, I have seen have been self made and do not use any active controller.
What kind of observations do you have to support your statement?
Ps.
Most of them I have seen, and built, has been to play a game where you put a string on your tail and try to cut each others with the propeller. They were airodynamic stable.
This depends a lot on the cost of the model. For a powered model costing hundreds, or thousands of dollars, this is a wise addition because it protects the motor in the event of something going wrong (usually the control link dying)
However in RC gliders (slope especially) it's not necessary - the plane is made of foam and will bounce off any obstacle with minor damage, and they don't fly at long range. It's quite uncommon in this type of flying.
I've flown flying wing gliders that didn't have a flight controller - they work just fine. They're very aerobatic, though, which is less than ideal for carrying passengers.
The main issue I can see with this flying configuration is that the Centre of Gravity is extremely sensitive. You have quite a lot of leeway with a conventional airframe, but with a flying wing the CoG has to be spot-on or it becomes uncontrollable.
>However in RC gliders (slope especially) it's not necessary - the plane is made of foam and will bounce off any obstacle with minor damage, and they don't fly at long range. It's quite uncommon in this type of flying.
If your reference is simple foam planes this is true. But in high-performance applications like F3F people will run on-board accelerometer based control units that stabilize flight.
The whole discussion is a bit silly though. The standard for toys is clearly not the same as for a passenger carrying commercial airliner, even if sometimes they are very expensive toys...
I can see why this might seem like the case with present time flying wing aircrafts. But most of the initial design and theory for the flying wing design (such as the Horten Brothers) was actually done on a glider which is passively stable. Most, if not all, military fighting aircraft (like the F and B series) are purposely designed to be dynamically unstable since this allows much faster control and reaction time at the expense of special computer and ASICs to maintain aircraft stability.
I don't think things like the Northrop YB-35 had much in the way of computer control. Never heard about flying wing aircraft being intrinsically unstable. Maybe the designs you've heard about were (things like fighter jets are designed to be unstable)
One could argue that as a result of the B737-MAX fiasco, no matter how small your change, you are likely to be required to go the full recertification route. This being the case, why not go big? You have to recertify anyway.
Disclaimer: I am not an aviation expert, and don't know what I'm talking about.
This video (shot from a chase car) of a B2 landing demonstrates the challenges with an configuration closer to a flying wing than an airliner: https://www.youtube.com/watch?v=ih57FiOeZXU
Wow. The criticisms I've seen about using flying-wing designs for passenger aircraft (planes that look like the B-2 bomber), are often focused on how bad the boarding process is for the movie theater seating they require. This design looks like it eliminates the seating problem pretty well. Flying wings have been known to be more efficient for a long time; logistics problems are the devil in the details.
Yet the image provided is the most radical representation I have seen of the "flying wing". This is two fuselages in V by initial look. I would still think that you could simply provide a screen for the interior passengers to have a view out, from the opposite side of the aircraft. People have done just fine in the center rows of jumbos so I am not sure that the negative impact is high as imagined.
The thought experiment to play with is, swap out windows for computer displays, still with the air gap seen on some planes, but not for all windows and see what transpires.
Not sure if there is "reason" for forward facing seats (perhaps crash safety? If so, why not put them all backwards since that is safest?)
I could imagine seats facing "outwards", with a corridor along the windows. Kinda like a cinema but the screen is replaced by a row of windows. This way no one gets to "hog" the window seat (apart from the front row, and even then others can still see the windows on their walk along the corridors to the toilets etc). Bonus points for raised stadium-style seating with storage lockers under the rows at the back.
We fly an aircraft with "club seating" (two rear facing seats facing two front facing seats). Experimentally, my son who is prone to airsickness has a harder time in the rear facing seats [which are closer to the center of mass and center of lift and so experience less excursions in turbulence than the forward facing seats, yet he is sicker in the rear-facing seats].
I'd guess the G-forces of take off would be quite uncomfortable if seated backwards facing. You'd be pressed into the seat belt rather than into the seat.
Are takeoff G-forces actually higher than braking G-forces at landing? I think they're probably comparable given the speeds and runway lengths are similar, so you would just be swapping the seatbelt discomfort from the end of the flight to the beginning. You could also probably make the seats pivot slightly to counteract the plane's angle of attack causing discomfort.
Braking is higher G but consider that the descent and landing aren't really nose-down situations and the braking part itself takes seconds. When taking off you have nose up for quite some time throughout the climb. Sitting backwards would make it pretty uncomfortable unless the seats are somehow redesigned (they'd have to be anyway to handle the different stresses).
I'm not an expert on this issue in any way, but my instinct is that there would be more acceleration during take-off. When landing, the plane has already decelerated to just above the minimum speed to maintain lift (nearly stalling), and doesn't have to come to a complete stop on the straight part of the runway before turning off to wherever it's going to de-board. Conversely, during take-off the plane goes from zero to hopefully well above the speed to generate lift.
My instinct was the opposite. I happened to be on an A321 this AM so measured it with my phone.
Acceleration was about 0.4 g with peak of 0.5 g. Second stage climb (5-10K) was 0.2g nose up. Rest of climb was 0.1g. Decel was 0.3-0.4 g also with a peak at 0.5 g.
On the big engine Lears, I’m quite sure the accel is higher than braking plus reversers. Airliners might also have higher accel rates on shorter runways as they often do power limited takeoffs on long runways in the interest of maintenance economy.
Related, we had a hold for weather at the destination, so I checked the pitch of the plane in the hold. It was 0.1 g nose up, which was quite noticeable when walking up the aisle to the restroom.
It's not that easy to make a screen that looks anything like a real window, the main reason being that the perspective won't change when you move your head.
Fair point - I was on a plane and on landing saw the wing flap act in an unusual way (didn't fully open compared to other flap and seemed like it was limited/stuck on one edge and one end raised more than the other and down end shaking and wasn't what I'd seen on that type of boing before). I pointed this out to the staff, who thanked me. Might of been nothing, and not something you follow up or indeed, how you would follow up. But equally, may of been sign of something amiss.
>However, aviation regulator the European Aviation Safety Agency said [in reference to windowless planes]: "We do not see any specific challenge that could not be overcome to ensure a level of safety equivalent to the one of an aircraft fitted with cabin windows."
Don't they just need windows at emergency exits? Passengers are already supposed to await cabin crew instructions before they evacuate, and passengers probably aren't really that great at evaluating danger aside from the obvious signs like fire or being under water, but the exit door window would also tell you that.
Maybe, though such footage would be useful in a black-box for post-incident/post-flight analysis as a visual comparison to the recorded control/instruments - could only help.
Only partially. Ever tried bending forward with the seatbelt on in the plane? You can easily reach with your upper body to the seat in front.
In case of a crash, the seats will move forward and then spring back, if you have your body in between of the two seats in front of you while they do this, you can easily get crushed.
Heart disease, possibly incurred from cocaine use, was his cause of death. The luggage hitting his head after the tire blowout was ultimately not the cause, though was initially reported that way.
My understanding is that the YB-35 flying wings had difficulties with stability along the Y axis, part of the reason they weren't suitable as bombers (for dumb bombs).
Aerodynamically the wetted area that generates drag without lift is undesirable. You need a wing generate lift, but everything else is there for something else like stability, handling, payload etc.
In conventional "tailplane" configuration the fuselage and tail are just providing drag and almost no lift (tail has little wings 'upside down' generating negative lift and trim drag). If you have canard or some more exotic wing configuration you can have all wings generating lift but there is still drag from the body. In clean flying wing, there is nothing else except the lift producing wing.
But thick, deep wings are not exactly known as the very definition of aerodynamic efficiency either. Are we sure that a sleek long tube added to a well-designed wing can be beaten by a wing that is full of compromise to accommodate seating?
Concerning the horizontal stabiliser providing negative lift: it's possible and frequently so, but not necessary for stable flight.
(If I understand correctly, what is required is that its angle of attack is lower than the one of the main wing, or equivalently (if the wings have the same shape) its wing loading.)
Yes. That's not theoretical requirement for tailplane.
But as the source you provides say: "indeed most aircraft operate with negative tail lift most of the time."
In practice all commercial aircraft have the center of mass so much forward that require negative lift for stability. If you look at the cross section of the horizontal stabilizer, it's like wing upside down.
My understanding is that airlines like to load their planes such that the CG is such that the tail contributes basically no lift, to minimise drag and fuel consumption.
Not entirely true. In a flying wing there is constant flap adjustment needed to counter balance a CG (center gravity) offset. The amount of counter drag is higher than a narrow winged tailplane. Obtaining a correct CG is therefore also more crucial. With variations in passengers and other load this will be a challenge.
To get flying wing stabile you have to add aerodynamic twist to wings which also adds drag. Flying wing looks good, but it's not as efficient as people think. It also has some unwanted flight characteristics like jaw hunting which are missing in t-tail planes.
Note 1: Boeing once toyed with a blended wing-body, a sort of flying wing, to produce dramatically better aerodynamics and fuel efficiency. Passengers would have sat in a wide cabin, rather like a small amphitheater. But tests with a mock-up produced such a negative reaction that the company dropped the technology, except for military refueling aircraft.
Unfortunately the source of that note, an article in the Economist from 2006, doesn't indicate when they tested. Standards and expectations of airline passenger comfort have degraded significantly over the years, so it might be reasonable to retest.
Although, I found an article from 2018 [1], quoting a Boeing VP of Product Development and Future Airplane Development, which basically says a blended wing design for commercial passenger aviation is unlikely because the required minimum height for passenger loading implies a minimum width that is quite large, and may not be very compatible with existing airports.
In the UAV world, the longest endurance loiter time fixed wing craft are either relatively slow and with long, straight wings (the 30 hour version of the rq-9, or the global hawk), or are flying wings...
> The Global Hawk has a wingspan over 50% as long as an A350, yet it weighs 1/10th as much. There is no comparison.
I agree that there is no comparison - in the sense that the two cannot be compared that way. For example: A childhood toy of mine (a compressed-air plane) needs a wingspan 1% as long as an A350, yet it only weighs 1/1,000,000th as much - and can still only stay airborne for 30 seconds!
This discussion [1] on the different most-aerodynamic plane shapes is fairly interesting, and certainly doesn't confirm the person above who claimed that a flying wing is the most aerodynamic shape.
> Sure, but those are not features you want in a cargo or passenger aircraft
Depends on the use case: for a feeder aircraft (regional to international airport) load, range and speed isn't terribly important, but fuel economy still is, for economical reasons (and for ecological reasons, which translate into economical by making the tickets an easier sell to a climate-aware population). In well developed regions, the main draw of feeder planes over ground transportation is not travel speed, but the convenience and piece of mind of checking in at your home airport.
Since a lot of regional (or effectively regional) airports are wildly overbuilt in hopes of attracting bigger connections there could be a market for a plane that fills the available width with a modern high aspect ratio wing to max out efficiency for small loads. If new aircraft designs weren't prohibitively expensive or fuel would be much more expensive this kind of plane would exist. Basically, put the wing of a Global Hawk on an ERJ-145.
> Sadly for the Flying-V, it will probably fail like the blended wing body designs we've seen down the years. It's for the same reason, too: airplanes bank as they turn. That's not much of a problem in a conventional airliner design, where passengers are never that far from the plane's central axis. But as you move further out from that central axis the effect becomes a lot more pronounced.
...and at it's first public outing, the test pilot dropped it in the trees at the end of the runway. That would have likely killed a new aircraft manufacturer.
I wonder what the comfort level would be like in a rough landing being so far left/right of the center of gravity if the plane was doing a lot of rolling corrections?
That's the problem. When passengers are seated too far from the axis of rotation they're in for a nausea inducing ride.
Designers could reduce the problem to an extent by building a double deck passenger compartment and putting the baggage compartments out toward the wings, rather than the current standard design which places passengers on the upper level and bags on the lower level. But there are limits to how well that can scale. I'm skeptical that we'll ever see flying wing or blended wing body designs used for airliners. Cargo and military applications are probably more realistic.
The proposed design puts the cargo on the inside of the V to maximize good views, and probably helps with logistics. I imagine the novelty of looking forward while flying is a selling point.
> That's the problem. When passengers are seated too far from the axis of rotation they're in for a nausea inducing ride.
What if the seats far from the axis of rotation faced sideways instead of forward? People don't seem to be as affected by pitch changes as they are by roll changes, probably because we are get a lot of exposure to pitch changes whenever we drive in a hilly area.
The angular change is negligible in either case. The problem is you're ping-ponging vertically. For example, a 3 degree bank correction in an aircraft with a 70 meter wingspan will move each wingtip by 1.3 meters vertically.
In the picture, the passenger cabin appears to be using only 1/3 of the wingspan, so the vertical movement of the outermost passengers (in the last row) will be much smaller than the vertical movement of the wingtips.
A last row width of 25m is much wider than the 5m of a conventional aircraft, but much smaller than 70m.
What if we place lift-fans in these undesirable areas? One in the center of the V and two out in the wings. Basically, instead of banking the aerodynamic savings we spend it on hauling dead-weight associated with VTOL operation. That could kind of make sense.
There is research done at a big American aircraft manufacturer which determined a limit on how far you could comfortably position passengers outboard. (I believe it was 13m). This airplane respects that limit, the outboard sections are used for cargo and fuel.
Disclaimer: I work at the same research group at the Delft University
However, judging by the window placement, the passengers furthest aft are maybe twice as far from the center of rotation compared to a widebody? That's far better than any other flying wing/blended wing concepts I've seen to date.
[edit] Also the traditional place for first-class travellers will be no further than in a widebody aircraft, so the people for whom the airlines actually care about comfort will be unaffected.
I'm not seeing a problem with banked turns, only high roll rates. During the turn, so long as it's coordinated, everyone, regardless of position, should have the same experience.
It's entering an exiting the turn where you could have some greater effects. But again, so long as you use a slow roll rate, it shouldn't be too noticeable.
Not even on a rough landing, just banking maneuvers on take off and landing. The prevailing winds and local mountains at my local airport require a banked turn of some sort for almost every flight. I can usually feel the banking in a typical passenger plane. Imagine what it would be like in the seats furthest from the rotational axis of the plane!
These wings will necessarily be much more rigid, as they are far thicker than traditional wings and pressurized. One thing not mentioned here is that that flexible wings act as a suspension system for an airliner; I'd expect that in a Flying-V you'd feel more turbulence.
The wings will be more rigid (and will have lower bending loading because the payload is more evenly distributed along the wing span), but any roll rate will cause the passengers to experience an acceleration. Maneuvering flight will not be pleasant for the passengers.
I remember watching a documentary a long time ago and they said that this design (or one similar) had the draw back that people would feel the turns much more since they would be further from the centre.
Have you never noticed the airframe itself flexing? When I look down the aisle from a back row seat on a turbulent flight I can see some pretty big oscillations in the fuselage. Still, it is not uncomfortable, mostly because the frequency is pretty low.
Why shouldn’t they? They’re providing a service that people pay for because they find more value in taking the flight than an alternative use for that money. Presumably, the value of that trip is largely uncorrelated with the type of aircraft, provided the inflight experience is bearable.
If we want to transition to hybrid planes, or entirely electric planes, these sort of efficiency increases will be very useful. I would consider the '20% efficiency increase' in that context.
That's mostly from a global perspective. From a business perspective, increasing efficiency without sacrificing customer satisfaction increases your competitive position, and would be a good thing, not?
Maybe going to full airliner size in the first step is just too big of a delta to take on at once. A flying wing business jet might be an interesting intermediate step (especially interesting for extravagant billionaires who would like to impress in style, I guess).
That's a nifty idea: put all the fuel and luggage out towards the wings and the passengers down the center. No more discomfort for passengers (during turns and turbulence) and you'd still reap the benefits of the BWB design. Though this would block window views...
Looking at the design, the first thing that occurred to me is that it looks like the frontal surface area would be increased compared to a traditional commercial jet with the same wingspan, which I would expect to negatively impact fuel efficiency. I did a bit more thinking and some reading to try to determine why this isn't the case.
For one thing, while the split fuselage in the images appears similar to that of a conventional airliner, I expect it would actually be considerably shorter than that of a jet with comparable capacity, the reason being that much of the luggage and equipment that would normally be stowed below the passenger compartment could instead be relocated to the center of the 'v'.
You would still have somewhat more frontal surface though I would think. Perhaps this could be outweighed (no pun intended) by weight savings and lower surface area. Although I wonder if some of the savings would have to come from flying more slowly, which this design might facilitate.
I don't know anything much about aeronautics though, so would love input from someone who does!
Nobody is building this plane (yet), KLM is just funding more research, any commercial airliner based on this technology is likely decades away. The 787 took about a decade to develop and it's based on a more traditional platform.
Hmm, looks like an x-plane screenshot. It wouldn't surprise me if they've been prototyping with planemaker (included with x-plane).
IMHO interesting concept but the thing to be investing in would be electric engines (hybrid or battery) as that will cut fuel costs a lot more potentially. 20% is an incremental improvement and potentially not good enough by the time this gets productized and never mind the time when this gets retired a few decades later (in the best case). So, in short, I think this won't fly (bad pun, sorry) because it's not anywhere near good enough by the time it can reach the market (15+ years?).
A lot of the proposed efficiency improvements involve new engines, new fuels, or new materials. This is a new design which could stack on top of any of these other improvements. Including a hybrid or electric engine.
Maybe but the primary driver of this design is the fuel tanks and weight distribution as well as the need for having big heavy jet engines.
This thing still takes about 140 tonnes of fuel. That's a lot of money to fly from A to B using a plane that is still a decade+ away. All I'm saying is that 20% cost reductions is not nearly ambitious enough for that type of long term project given the stuff that is already happening today and given the stuff that is likely to happen in the next decade.
IIRC there are rules that any catastrophic engine failure must be contained. The Concord was granted an exception and that didnt go so well. Degree going out the back and hitting hydraulics was the cause of some other incident like Sioux City Iowa.
The engine placement is also problematic for maintenance. Airlines prefer to buy aircraft that their mechanics can service with just a short ladder. That's one of the main reasons why all recent designs have engines only under the wings.
Why does it look less aerodynamic than a normal plane? Isn't a rocket or missile like shape the most aerodynamic one? Planes are pretty close to rockets with thin wings for maneuverability. Fling V has so much surface area being pushed against the air, I am honestly surprised at their claim of being 20% more fuel efficient.
In term of pure drag, you're right, you want to reduce the surface and that's not what this design does.
However, for aerodynamic efficiency it is the lift/drag ratio that matters.
And while in a normal airliner the body provides very minimal lift, here it's basically a wing and thus generates a lot of lift.
The end result is that while the drag is probably worse, lift is likely improved enough to compensate.
(Also, drag might not be that bad given you do not have a tail, which is pretty awful aerodynamically speaking)
if tube and wings design is to change, i think it will be some less radical changes than flying wing, more along the lines of transitioning the tube into the lifting body, while may be not the full way along the Burnelli http://www.burnelliaircraft.com/wp/ , instead more like the modern version https://en.wikipedia.org/wiki/Aurora_D8 :
"The aircraft is designed to be over 50% more fuel efficient[1] compared to aircraft currently under production."
I'd be interested in how they would manage weight distribution as well. Will the plane still fly in a situation where passengers on one side of the aircraft need to be on the other side?
that looks like a deicing SNAFU just waiting to happen. that's a lot of surface area that has to be de-iced to ensure nothing breaks off and enters the engines at the back.
It would be a significant time investment to be checked out in a radically different type like this, but not impossible. It mostly comes down to the systems, avionics, and procedures which can be radically different already, even in similar-looking planes.
I also wonder about engine placement. Engines on top will push the nose downwards in case of adding more trust. There is also issue of stalling on ascend. On ascend, wings would very easily obstruct air going into engines, reducing their power. Also currently aft-mounted engines require vertical stabilizer to be above them to counter act the forces generated by the engines. I don't see any vertical stabilizers in this concept.
after some clicking you can see the '2% lighter' claim on a demonstrator, here: https://www.jbenad.com/flyingv which makes me even more dubious about this whole thing; the claim is that this configuration fits in the dimension of the airbus is compared to, so by logic alone the increased surface area should end up in a greater weight, and that's without considering the increased structural elements that are required to avoid flexing and twisting of the two heavy sections to which the rear wings are attached, which have a lot more momentum than your usual wings, since they carry more weight and farther than the center of mass/rotation.
I also wonder where would the fuel be stored. needs to be around the center of mass and lift, to avoid the com shifting around as the planes flies. and there aren't wings there conveniently placed near the com to store it, so, is it going to end up below the passengers? that'd be a huge safety hazard.
Is there greater surface area? One way to look at this design is to take an Airbus 350, take of the wings, bend the body in a V-shape and, finally, flatten it to make it generate lift.
That won’t be exactly correct (for example, flattening the body will decrease volume, and, likely, max # of passengers), but given that it has the same passenger capacity, I would think it’s a decent approximation. So, if you need extra material, the loss of those wings gives you some room before the resulting plane becomes heavier than a A-350.
Fuel is fuel, wherever it goes there is a safety consideration.
The last crash I saw on the news had something nasty going on with the engines hitting the tarmac, the above wing placement of the engines is a safety feature as I see it, even though that design choice is more out of consideration for noise - it should be quieter for those living under a flight path.
From the evolution of the bicycle to the mountain bike I can remember that a big, thin-walled tube is stronger and lighter than a narrow, thick-walled tube. I know planes are different, but bigger does not automatically mean heavier.
You could have all of the fuel at the back, behind the passengers and engines. The flight control surfaces and some thrust vectoring could accommodate that.
A U.S company called Boeing know a thing or two about making automatic systems for mitigating against a less than perfect centre of gravity. They went for less than ideally located engines rather than less than ideally located fuel. Allegedly there have been a couple of hiccups with this system but the general idea is that not even the pilots know that there is a computer accounting for changes in centre of lift/gravity, it just works.
On Airbus planes it has always been fly by wire. By 2050 - when this V thing is supposed to go into service - the idea that a human should fly a plane will seem daft, if the computer is doing it all anyway then the plane does not have to be dynamically stable or even balanced from side to side. It should be able to precisely balance out the shear forces no matter what the conditions. You could even turn the thing without banking.
Tongue in cheek criticisms aside, it is better than my student project and a nice thing for KLM's 100 year celebrations.
> You could have all of the fuel at the back, behind the passengers and engines.
That would cause quite the difference in handling between takeoff and handling. The fuel tanks span the length of the fuselage in this design — and I'm sure that's intentional.
Most weight savings come from the bending relief due to the distribution of the load over the wing span instead of concentrating it all at the wing root (which is the case for a conventional design).
I wouldn't say nonsense, but the problems are different and maybe worse.
Below: Engines can strike the ground. There is more debris ingestion, ranging from sand and burst tires to people and baggage carts. Noise regulations are harder to satisfy.
Above: Failure causes nose-up (as power is lost), which may lead to a stall. The aircraft sits lower in the water after a water landing. Being nose-up may put the intakes in slow turbulent air flow, killing performance and possibly stalling the intakes. Ice and rain may come off the body, to be ingested by the engines.
Some things could go either way. Maintenance is going to involve a crane or a jack to get the engines off.
Fuel use is generally measured per distance traveled, so that part is implicit in the claim. The passenger capacity is talked about in the next paragraph:
> What’s more, the Flying-V will carry the same number of passengers – 314 in the standard configuration – and the same volume of cargo, 160m3.
Hmm... I've never heard of anyone mean thermodynamic efficiency when talking about fuel efficiency of a vehicle. Maybe people who design aircraft engines do?
> The energy efficiency in transport is the useful travelled distance, of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means.
Ah, seems like then it's possibly a bit of column A and a bit of column B. I'll defer to you on the correction though, I was merely speaking from third-hand/watercooler type discussions about aviation as someone who is just a passive enthusiast of airplanes.
All airplanes are aerodynamic. There needs to be a mention of what exactly is happening to cause those fuel savings.
I highly doubt that those numbers are trustworthy considering how closely we are scraping fuel efficiency numbers, unless there is some performance metric they aren't mentioned that has degraded.
But in this extreme case of the fuselage being inside the wing and making it much thicker than typical and necessary, this isn't necessarily true, at least it's not obvious.
If this design actually provides the claimed results, connecting 2 such wings (one behind the other) with a long fuselage (i.e. >---> which would incur almost no additional drag and twice the lift) would be even better, no?
Think of it this way: A cylindrical fuselage provides no lift (except for the lift from its angle of attack flying obliquely through the air), only drag. If you can design the aircraft in such a way that all exterior surfaces contribute to lift, that would be ideal.
The "---" portion of your idea provides no lift, only drag.
The ideal flying wing is more efficient. The tradeoff to make a flying wing suitable for commercial aviation has historically made those efficiencies moot.
The main problem with flying wings, and probably this design too, is that they are inherently unstable, and without very precise computer control they are uncontrollable. Compare to modern planes that a good pilot can fly and land with zero computers, given some effort. (They are stable, and with no control inputs at all just keep flying in same attitude as they are currently in)
In a flying wing, computer failure is a certain airframe and passenger loss. I don't know any engineers who write flawless code. Do you?
This is patently false. In fact you should delete this post in its entirety because it's just wrong. Don't make these things up and post them as fact. Flying wings easily fly without any computers whatsoever. They are inherently aerodynamically stable. Only manual elevon inputs by humans are actually required and it is quite easy to control unless your center of gravity is too far back. The CG is usually around 70% of the way to the front from the back.
Instead of spending half your comment saying how wrong GP is, why not provide some compelling evidence? I was under the impression that flying wings are indeed more unstable than traditional airframes.
> After the wheels lifted from the runway, which caused the flight control system to switch to different control laws, the erroneously sensed negative angle of attack caused the computers to inject a sudden, 1.6‑g, uncommanded 30-degree pitch-up maneuver. The combination of slow lift-off speed and the extreme angle of attack (and attendant drag) resulted in an unrecoverable stall, yaw, and descent.
This seems to support GP's assertion that "without very precise computer control they are uncontrollable" and "computer failure is a certain airframe and passenger loss"
I think it requires a little more careful design then traditional plane bodies, so there is some sense in which flying wings are less stable naturally. But the claim that flying wings are necessarily unstable without computer control seems to be false.
Absolutely no one denies that the B-2 in particular is unstable, but it is one particular model designed to a particular set of requirements that are vastly different from those for a commercial airliner. It seems that the general public have internalize "the B-2 and F-117 are inherently unstable" as "flying wings are inherently unstable", which is incorrect.
To be even clearer, these two planes were designed with the goal of having the smallest radar cross-section possible. The lack of aerodynamic stability was worth the trade off (esp. since it could be compensated for by flight computers).
Uh, not really? Seems more like a failure of the computer. Don't know much about flying but sounds like a pretty extreme maneuver was attempted by the computer.
Flying wings that are controlled entirely manually exist. A favourite example (I know people that have flown these) is the Marske Pioneer[1]. An actual glider with highish aspect ratio wings that was and is quite flyable by hand
Not if you use an airfoil with an appropriate pitching moment, that's designed for flying wings. Look at all of the hobbyist models that fly just fine using very crude control inputs.
>In a flying wing, computer failure is a certain airframe and passenger loss.
The control sticks in an Airbus A320/330/350 are entirely decoupled from the mechanical control surfaces. All control inputs are going through "computers" in even the most manual of flight modes.
P2 was actually trying to get the nose down. The pilot flying was quite determined to keep the aircraft pitched up. They knew they were fighting on the controls, there was a voice announcement whenever it happened. The root problem was that they were not communicating with each other in an effective way. If P2 actually felt that strongly, he should of assertively stated that he wanted control (which he eventually got BTW) rather than trying to steal control. If he really felt strongly enough to mutiny against the authority structure, he should of whacked the pilot flying with the fire axe.
In a working cockpit, there should never be a question as to who is actually flying the plane...
AF447 went down primarily because of bad training, bad communication, and bad reactions by the pilots. Active sidesticks may have saved them as a last line of defense, but it isn't the primary reason the plane went down.
> "we’re looking into new options to having a rest or taking meals on a plane. Offering food from a buffet is one of the options we’re sinking our teeth in"
Based on the A380 "promises" of in-flight gyms/casino/salons/creches, I think we can safely call bullshit on this - we'll just get more seats crammed in as usual (in economy at least - perhaps first class will get these?). That is fine - I understand the economics - it is marketing I guess.