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Airframes

Old 22nd Oct 2017, 09:47
  #21 (permalink)  
 
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Originally Posted by megan View Post
Twas back in the day when IFE consisted of one large screen for the entire cabin to watch movies. Had travelled half way round the world to find myself at thirty plus thousand feet on a gin clear day over the Grand Canyon when along comes a CC demanding the window shade be pulled down in order to show some B grade Hollywood trash. Was appalled that everyone seemed to prefer the trash to the magical vista to be seen outside. Why the heck didn't Boeing put a window at row seven, or there abouts, on the 738 LHS. Had it a few times and not a happy traveller.
When I have a window seat, the shade is up. There's a great big world out there with wonderful sights.

I almost always get annoyed stares from pax sitting next to me.
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Old 22nd Oct 2017, 11:18
  #22 (permalink)  
 
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Originally Posted by megan View Post
Why the heck didn't Boeing put a window at row seven, or there abouts, on the 738 LHS. Had it a few times and not a happy traveller.
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Old 22nd Oct 2017, 11:25
  #23 (permalink)  
 
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Same on trains in the UK.
I use "X country" trains from Bournemouth to the Midlands now and then, and the windows cover two rows of seats. I like to have a South side seat (with the sun) passing Southampton docks to see the shipping, and usually the other row sharing the window wants the blind down so they can see their screen.
Bloody annoying!

When flying as pax I also want to see the great outside.
Went to Florida with the kids a few years ago, and booked RH window seats for the outward journey to give the youngsters a geography lesson all the way down the East coast of North America.
How are you going to do that without windows?
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Old 22nd Oct 2017, 19:42
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Pan/scan isn't an issue with an all-round camera and some software - think Google Maps/Street View.
You really want to compare that fish-eye view with the view out a window? Because as someone who truly appreciates the beauty of our world, it's not even close...
Maybe if we gave all the passengers one of those F-35 helmets - of course so much for any cost/weight savings.

Window sizes have grown since his book was written, so the weight penalty for newer aircraft will be a bit higher than that.
No first hand knowledge - it's well out of my area of expertise - but my understanding was they were able to go to the larger windows on the 787 because the composite construction minimized the weight impact of the windows.
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Old 23rd Oct 2017, 16:19
  #25 (permalink)  
 
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As I understand it then, the 787 has bigger windows to see the world through, but the cabin crew can turn the windows off so you can't see through them?
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Old 23rd Oct 2017, 18:41
  #26 (permalink)  
 
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25% of what? Because I can guarantee it wasn't airframe weight, or even fuselage weight...
It was 25% of the weight of the structural elements of the fuselage. The structural sections could be optimally spaced, and smaller not having to reinforce around the windows. There is the weight of the window assembly, and associated flashing to consider.

The window assembly, associated reinforcement, and extra strength for each member, vs a thin layer of aluminum?

How can you guarantee it is not 25%? Did you read the Airbus information?

How are you going to do that without windows?
As shown by the Airbus patent and the article. There would be screens instead of windows, and cameras mounted on the outside of the aircraft would provide the same view.

Airbus also patented the pilot in the cargo holds, aviating by screens and cameras. Likely a much better view than the current windscreens, an probaly much more roomier flightdeck.
One uses screens in the sim, so what is the big deal?
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Old 23rd Oct 2017, 19:18
  #27 (permalink)  
 
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Originally Posted by tdracer View Post
You really want to compare that fish-eye view with the view out a window? .

You're the one who said "The problem with view screens is unless you give every passenger their own camera ....."


I'm just pointing out that the technology exiats.


As for me, I think the idea is ghastly - I always take a window seat. But I don't think the beancounters (or Mr. O'Leary) will take that into account if it is ever offered as an option. Hell, they'll probably put it on pay-per view.
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Old 23rd Oct 2017, 22:50
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The industry might want to think twice before it argues that seeing it on the screen is as good as being there . . .
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Old 24th Oct 2017, 00:13
  #29 (permalink)  
 
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How can you guarantee it is not 25%? Did you read the Airbus information?
No, I didn't read the Airbus propaganda, but I do know this:
Boeing has been building jetliners for 60 years without windows (except for the flight deck and exit portals) - KC-135, 747F, 757F, 767F, 777F. Their fuselage structure is optimized for the lack of windows. Yes, it saves, weight, but the number is small single digits (the previous post quoting 200kg for 150 seater is ballpark). Once you add in a couple large view screens for each row, plus cameras, associated wiring and controls, it's probably close to a push.

Last edited by tdracer; 24th Oct 2017 at 00:30.
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Old 24th Oct 2017, 12:46
  #30 (permalink)  
 
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Boeing has been building jetliners for 60 years without windows (except for the flight deck and exit portals) - KC-135, 747F, 757F, 767F, 777F
I understand that, but Boeing doesnt build a different structural frame for the F models do they?

Now going back, I did say saving 25% on the fuselage structure? Thinner elements, no bracing and no windows? Not to mention ease of construction...
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Old 24th Oct 2017, 13:22
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This conference paper may be the origin of the 25% figure:

Aircraft Preliminary Design: a windowless concept
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Old 24th Oct 2017, 15:30
  #32 (permalink)  
 
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Dave,

thanks for that link!

The formula and calculations they give amount to about a 28% weight savings in the fuselage structure, including the windows vs screens




As already cited, a mass reduction in any system of the airplane implies lower fuel consumption. Than the total weight is even lower and, for example, lighter landing gear could be sufficient to carry the plane weight. This process could improve weight savings of about 25%.

TD, now about your guarantee.....
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Old 24th Oct 2017, 22:34
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The only non-window-related weight considered in the formulas above is the weight of the skin itself. (In the paper, the formula for skin weight is the formula for the surface area of a cylinder times skin thickness times density.) So the paper is really saying that the weight of a skin without windows is 25% less than that of a skin with windows. It doesn't take into account frames, bulkheads, or anything else that makes up a fuselage.

There are probably some structural savings that the paper doesn't take into account. But the total savings can't be anything like 25% of the weight of the fuselage as a whole. I don't think TD's going to be called to make good on his guarantee.
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Old 25th Oct 2017, 00:25
  #34 (permalink)  
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I recently travelled on an A-380 ,not a window seat.I may as well have been on a coach travelling through a long tunnel for 12 hours!So except for those next to a window the majority do not see a thing so get rid of them I say !If weight reduction and strength are improved then it has to be a good thing.I also flew many times facing the rear and it never bothered me!!
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Old 25th Oct 2017, 02:06
  #35 (permalink)  
 
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TD, now about your guarantee.....

Still stands - 25% skin weight is no where near 25% fuselage weight.
Oh, and did you take a gander at their "small scale validation model"? Validating a structural design change with a 3d printed chunk of plastic?
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Old 25th Oct 2017, 16:51
  #36 (permalink)  
 
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Still stands - 25% skin weight is no where near 25% fuselage weight.
Did you look at the formula?

So the paper is really saying that the weight of a skin without windows is 25% less than that of a skin with windows. It doesn't take into account frames, bulkheads, or anything else that makes up a fuselage.
Did you look at the formula?

What exactly do you think Window metal frame and near hole reinforcement are? Structural elements perhaps?

Perhaps if you READ the article, you will comprehend where the 25% comes from, or you could continue to blindly argue your point when provided with facts to the contrary.
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Old 25th Oct 2017, 18:01
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What exactly do you think Window metal frame and near hole reinforcement are? Structural elements perhaps?
They are structural elements of the windows. MOST of the weight of a fuselage isn't the skin and window surrounds - it's stringers, bulkheads, keel beam, floor and floor support. I've seen airframes going through D-check with all the skin and window surrounds removed - there is still a LOT there, which makes up the lions share of the strength and weight.
The formula you so proudly point at doesn't account for all that other stuff, except in a secondary manner (yes, lighter skin means some of the other structure gets lighter, but not by 25%). While the aircraft skin is a structural element - it's not the primary structure.
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Old 25th Oct 2017, 21:05
  #38 (permalink)  
 
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Originally Posted by Homsap View Post
Two good reasons to have windows is from a safety point duriing an evacuation in daylight hours, in the even of no electrical power, as I think was the case in the A320 landing in the Hudson river, it is alot easier to evacuate and for the crew to check the aircraft, Secondly, it is easier for fire and rescue crew to locate fire and people, that is why the blinds are in the up poistion for take off and landing.
Isn't another reason so that rescue crews can see in from the outside?
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Old 25th Oct 2017, 21:45
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The formula you so proudly point at doesn't account for all that other stuff, except in a secondary manner (yes, lighter skin means some of the other structure gets lighter, but not by 25%)
What you are unable to comprehend is that those systems are static, and the removal of the windows and associated reinforcement is a difference..

Note: the weight of the windowless fuselage vs the weight of the fuselage without windows.

What is your experience in the structural design of an aircraft fuselage?

Have you designed the structural components of a wing? of a winglet?

keep trying to defend your postion, it is rather amusing watching you flail on the hot pavement.

Isn't another reason so that rescue crews can see in from the outside?
Actually, no. Windows are required in certain locations for cabin crew to look out and determine safe exit. Hence the Airbus design I posted previously.
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Old 25th Oct 2017, 22:14
  #40 (permalink)  
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Might we maintain our cool a bit, chaps ? Play the ball and not the player ?

Although I don't know him, I suspect that tdracer actually is very well placed to make the comments above ....
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