Windowless aircraft
 

From an article in today's Telegraph business section;

Can this claim possibly be correct?

Here's the article; https://www.telegraph.co.uk/business...craft-virtual/

I'm shocked to see that at the moment I voted on the survey from your link , 65% of the voters are cool with that idea...:ouch:

Lately, I have found that 90% of the window shades are closed in an airplane 90% of the time. People are more likely watching a movie on their phone or tablet.

If you eliminate the weight of the windows and reinforcing structure, you could easily replace them with an array of OLED screens for an outside view.

If you look at the weights of the b747F or b777F versus the weights of their passenger equivalents (the ones with windows), you will see that they are nearly identical. So the 50% figure is ridiculous.

What I would like to see , from a distance, is when Sir NummNutt goes much faster and much higher with his windless 777WL.
I hope he is the only one aboard.

The problem is that these days when You lie so absurdly and are so incompetent , people think: Oboy, he is the boss and make 1000x more then me, so he must be right!

Pretty much beat to death here:
https://www.pprune.org/tech-log/600907-airframes.html
Short version, group claimed they could save 25% of the skin weight if windows were eliminated. However the skin weight is a small percentage of the overall aircraft weight, so the total weight savings would be small.

I pretty much concur with what Intruder said, seems like nobody want sunlight spoiling their video screen, and when the CC come around and ask you to drop your shade it takes a lot o bottle to not to look like a jerk by refusing.
So that leads us naturally to the concept of a blended wing airliner in the future.
I love looking out of the windows, but if I had the option of a choice of external camera views then I could be happy.
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Never mind the lack of windows, I don't believe anyone has yet come up with a solution to the motion sickness likely felt by passengers in seat 1A or 3Z when a blended wing aircraft banks.
You'd definitely need to "keep your seat belt firmly fastened at all times" if you're sitting out near the sharklets.
And as in a boat, lack of a visible horizon would not help.

Passenger evacuation would be rather interesting in a blended wing aircraft. Our present tubular shaped aircraft allow doors to be fitted down the length. Where would the evacuation doors be placed on a blended winger to allow emergency evacuation in the allotted time?

Why does it have to be all or nothing?

Real windows every third row for example would lessen weight, reduce claustrophobia, and enable cabin crew to see outside as necessary. Window-loving passengers could have the fake screen or an option to pay more to sit next to a real one.

Evening all,
very interesting thread.
I concur on the BWB question... because that's the planform this whole question of windowlessness relates to in my view; not tubes with wings.
If I may tell a story, many years ago, found myself in a media conference with one Randy Tinseth of Boeing.
I asked him why they hadn't made a BWB (no brainer, fuel, range etc). and he said it was all down to customer perceptions.
Yes, Bob Liebeck back in the Douglas days had done a lot of work on the BWB, but at the end of the day, passengers would get airsick in turns, and who wants to sit in a seat with no windows?
To which I say, bull****.
The reality is a BWB fuse is going to carry pax broadly in the centre section... maybe two or three traditional circular or ovoid fuse widths out from the centre line at the max?
They're not going to be out near the winglets... please.
Now, what's the max angle of bank that a large airliner will fly when manoeuvring in the TMA?
I'm not smart enough to do the sums, but really???!
Is a passenger going to get that airsick?
If that's a risk, then why not design the airways and approaches to large airports so that your ultra-heavy Boeing 818 BWB doesn't exceed a certain angle of bank?
I reckon on the surface of it, it's down to the windows issue - and the reality is, on long haul, all most people do is watch movies or sleep.
Very occasionally, they look out the window.
But the real reason is that mother Boeing doesn't want to make her whole product line obsolete in one fell swoop, by building a lovely big flying wing, that is an order of magnitude more efficient than the 787.
Maybe some engineers can offer their views here?

Air sickness isn't caused by banking. Motion sickness is caused by the balance system's inertial sensors (the inner ear) sending different motion information to that sent by the eyes, which confuses the body's control system. That's why you get (bad) motion sickness on the jump seat of a jetstream 31 (the one at the back of the cabin) if you look out of the only window you can see (the centre windscreen panel). Your vision and innertial sensors see things on opposite ends of the seasaw pivoted at the CG (to keep it simple). So when you get yaw-bumped left your eyes see it as bumped right, and the same with pitch-bumps.

PDR

I want bigger windows.
The beautiful scenes I've witnessed outside an airliner window just don't compare at all to the rendered image on a small screen such as an iPhone in the hand.

Sir is talking out of his orifice.

I do love to look out the window, if I can get a window seat. Couldn't believe the CC who came by on a LAX - NY trip early 80s, beautiful weather with the Grand Canyon below in all its beauty, and demanded the blind be closed so they could show the B grade Hollywood trash on the big screen. No better these days, departed midnight on a Singers - Copenhagen last year and wheels were no sooner in the wells than a demand for closed blinds was made. Thinking why do they have windows, asked and told pax get upset by the sunrise streaming in the window, on a west bound flight? Still, spent many an hour flying as a pax in windowless C-97, C-130, C-121 without complaint. Boeing, bring on the BWB - with hi def video of the outside, sitting in the centre of any current airliner, or aisle of a narrow body, you effectively have no view of the outside.

The no-brainer is not that simple. And apparently it's also down to the aircraft manufacturer's perceptions.
Perhaps you'd care to see some more recent comments.

Recent comments from Boeing

Potentially, yes.
My understanding is that it's not just about bank angle but about the effect of continuous up and down motion.
And, of course, the potential for either positive or negative G is magnified with distance from the centreline.

Sorry. I was exaggerating for effect. Next time I'll flag it so you know.

An interesting comment from the link that I posted at #15.

U.S. military cargo planes carry a lot of passengers and don't have many windows so they obviously aren't necessary, but I certainly prefer having windows.

Something i too have been thinking about for some time, a small camera with a screen inside. I am no engineer, but i would imagine it could be operated at a lower cabin altitude that what we are used to as well.

Still trying to figure out where the emergency exits will be on a blended wing aircraft. Dropping straight down is precluded because of the possibility of gear-up landings. Out over the top? Don't think so. How wide would the cabin be? People toward the center would have an interesting time.
Back in fifties, Seaboard and Western contracted to operated daily Super Connie service for BOAC from IDL to BDA. The aircraft were all coach L-1049D Super Constellations. They were convertible freighters. Inside, a row of Green Curtains ran down each cabin side and, when pulled back, revealed mostly blank sidewall except for four windows on each side. After a few weeks of irritated pax complaints, BOAC threated to cancel the contract. S&W hurriedly bought an L-1049E from Cubana. LASNY converted it to high density coach for the service and with its full compliment of pax windows, it flew the service.
Meanwhile, the L-1049D's four window Connies were used fro MAC charters. If the Gi's complained, no one listened.

You can't "extrude" CFRP. You can "pultrude" it (as for carbon arrowshafts) but that puts the fibres parallel to the long axis, and the principle stress in a pressurised fuselage is the hoop-stress from the pressure. The fibres in a pultruded fuselage run the wrong way to react this, so the tubve would be weak for its weight.

I'm not sure what you mean by "spin", but you could lay fibre onto a former in the way they do for glass/carbon pressure vessels (used in chemical engineering). It's an expensive process as essentially each fibre is individually placed, and you'd need an autoclave large enough to take an entire fuselage to cure it off. But the main problem with this kind of structure is that you'd need to add subframe assemblies to mount things like wings, tails, engines, floors etc, and these don't integrate well with that kind of structure. Working out how to do doors, windows and access panels is a bit of a challenge as well.

The other option would be to use dry-woven tube (aka "sock") which could be laid over a former and tensioned to shape. I suppose you could also put it in a female mould and inflate a balloon inside it to create the shape, but that sounds like a very fiddley process to get right while the resin is curing. This is how carbon tent poles are made. The snag is that the actual fibre orientation is a function of the local curvature of the shape rather than being a specific angle determined to suit a stress requirement. You'd also have no fibres running axially down the tube, so it would be poor at taking bending stresses. Again, doing doors, windows, hatches amd mounting points would be a real challenge, so it would probably need longerons and some kind of hoop-frames to attach things to.

Carbon is a high-strength material, but only in tension. That means that you would end up making thin sections (because you don't need them any thicker to take the loads - that's where the weight-saving comes from), and these thin sections would need to have stringers or other supporting elements to give them the stiffness to take compression loads without buckling. So what you end up with is a complex structure - just as we do with metal, wood or any other material. I'm afraid there aren't any short cuts!

PDR

Incidentally - the difficulties of stressing the structure to take pressurisation loads is just one of the many sub-optimalities of the blended-wing concept which doesn't seem to get mentioned much.

PDR

This old study would suggest the BWB has many advantages over and above the current tube with wings. Boeing has certainly invested some serious money in the concept, having built a BWB wing box and air freighted it by Guppy from the west to east coast for testing.

http://citeseerx.ist.psu.edu/viewdoc...=rep1&type=pdf

http://www.dailypress.com/news/scien...212-story.html

There are lots of issues, but one of the major ones is that you can't get "family savings" for a suite of designs for different range/seats combinations. In the conventional layout it's quite easy to do variations (eg A318/319/320/321, or the plethora of 737 variants) optimised for different route/block patterns, but with the blended-wing concept pretty well the whole aeroplane has to be designed for a specific route and payload leading to niche aircraft with limited markets that won't service the investment requirements. This is similar to what happened to the A380, but more extreme. The concept only really seems to work with very large passenger loads, and as the A380 also showed there are only a limited number of uses for that kind of aeroplane.

Maintenance doesn't look straightforward - the engines are high-up and fully enclosed and would need fuel plumbing (presuming the fuel to be mainly in the outer wing panels) that somehow routes around the pax who are between the fuel and the engines. And I still don't see how they intend to make the pressure hull work without excessive structure weight or unacceptable stress concentrations.

And even that study report glosses over the evacuation issue by saying that they'd need to work with the FAA to produce some "new requirements". The lawyers would have a field day with that one if one ever caught fire or ditched...

PDR

Something the FAA does when the occasion arises, as with new requirements for FBW helos. I wonder if the burgeoning market for air travel, clogged airways, real estate available for airports, will see a movement towards larger aircraft.Return of the 1011 & DC-10. No problems with routing fuel, all three engine jets managed, and most, if not all jets, have pax sitting on top of fuel tanks - centre wing box and maybe tanks in the hold.

PDR, the FAA (and EASA) routinely issue "Special Conditions" and Issue Papers during the development of a new aircraft. Special Conditions are typically used when new technology isn't adequately covered by the existing regulations. For example, when FADEC was first introduced, there were no meaningful regulations regarding Electromagnetic Interference (EMI), so there were special conditions for HIRF/Lightning resistance (it took another 20 years before the FAA actually finalized regulations for HIRF - so all the Boeing FADEC and FBW installations prior to the 787 were covered by Special Conditions. Issue papers are used similarly when meeting the letter of the regulation may not be 'adequate' and to make sure that the method of compliance used is acceptable. There is also the ever popular "Equivalent Safety Finding" - where the design may not meet the letter of the regulation but meets the safety intent of the regulation (Boeing thrust reverser installations post-Lauda have all used an EFS - the FAR says the aircraft must be controllable - that's not practical (maybe not even possible with big high bypass engines) so Boeing has instead designed the system so an in-flight deployment won't happen. Granting an ESF requires an Issue Paper on the subject.
This is all long standing SOP (due to all its advanced technology, the 787 had a huge number of Special Conditions, Issue Papers, and ESF). Boeing would be negotiating with the FAA and EASA on the requirements long before it formally launched any blended wing/body aircraft.
IMHO, if we see a blended wing aircraft, the first one(s) will be for the military - likely some sort of cargo aircraft.