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Engineers are exploring radical new designs for commercial planes

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Re: Engineers are exploring radical new designs for commercial planes

#81

Post by HPsquared »

thot_experiment wrote: post #66
HPsquared wrote: post #47

Earlier quoted context omitted.

In a typical plane in turbulence, you can see the wings bending up and down. Perhaps a blended wing would be stiffer, though.

Yes a blended wing would be stiffer, but wing stiffness isn't really relevant here. The wing bending isn't evidence of differential pressure between the two wings, it's only showing that the wings are the part of the plane that's most affected by turbulence while not accounting for the majority of the inertia. The point is that air currents powerful enough to appreciably affect a large plane are large scale and there…

Ah, so in other words the whole plane bumps up and down but doesn't rotate. Therefore the location of passengers doesn't matter much, as all locations experience the same acceleration. (Provided the cabin is stiff)

Re: Engineers are exploring radical new designs for commercial planes

#82

Post by dr_orpheus »

scarier wrote: post #69
VBprogrammer wrote: post #43

Earlier quoted context omitted.

Across the wings yes but not across the majority of the fuselage.

How is that a meaningful distinction from either a design or manufacturing standpoint?

Because the fuselage is pressurized. And it is convenient to have pressure vessels as cylinders for even distribution of of the pressure forces across it. Ideally you want to have it capped off with two hemispheres (think propane tank shaped) but obviously you can't do that for other reasons. So there is likely more design and manufacturing for the front and rear of the plane than the main section.

Re: Engineers are exploring radical new designs for commercial planes

#83

Post by abeppu »

JustSomeNobody wrote: post #19
alexpotato wrote: post #5

Interesting historical note on the blended wing design: One of the main arguments against it was that designers weren't sure if people would be ok with sitting towards the center of the plane. The thought was that passengers wouldn't be comfortable without being able to at least see outside (even a little, looking at you 3/4/3 widebody planes). I mention this b/c there is a quote in Mary Roach's Flying to Mars. She m…

Anecdotally, I hate flying if I can't see out the window. Like, really really hate it.

I get this, but also peering out a narrow plane window at a view which is often at least substantially blocked by wing is not always fun.

I would like airlines to put a 360 degree camera system mounted to the exterior, and pipe through the feed either to a channel in an in-seat screen, or make it available to passengers wearing a VR headset. Imagine one of these much wider planes where many more seats are middle seats -- but where you can sit down, put on a VR headset, and get a clear image of the view in every direction. If fewer people will have a window in these future planes, and most awake people are looking at an entertainment system anyways, I would like the airline to pipe through a feed from a 360 degree camera mounted on the outside. Imagine sitting in a middle seat, comforted by the fact that you can put on a VR headset and

Re: Engineers are exploring radical new designs for commercial planes

#84

Post by jabl »

AlexandrB wrote: post #7
ramesh31 wrote: post #4

I remember seeing renderings precisely like this in my middle school textbooks in the 90s, claiming the same thing. The truth is that commercial airliners are a solved engineering problem. We are at the absolute limits for speed, reliability, and safety that can be achieved with a flying machine in the earth’s atmosphere. Which is why the fundamental layout has not changed since the 707 was introduced over 60 years a…

Yup, I've been seeing these futuristic airplane concepts for most of my life, but commercial airframes seem to be converging to be more and more similar. Unusual elements like a third engine in the tail or horizontal stabilizers mounted above the rudder have largely disappeared. Given the thin margins in air travel, I suspect this is because this design is the most successful. It might be a local minimum, but when it…

Horizontal stabilizers above the rudder went away with the engines mounted on the body in the back, the reason for the high tail was to keep the elevators away from the jet blast of the engines.

As to why create a design like that in the first place, I don't know. My understanding is that the 'engines under the wings' layout won because with the engines in the back the fuselage needs to be stronger (and thus heavier) to support the engines.

(Business jets tend to still have the engines in the back layout, because mounting the engines high allows shorter landing gear so that a stair that is part of the door is enough to board the plane, no need for an external stair. But that's not much of a consideration for a passenger plane operating out of airports with infrastructure available.)

Re: Engineers are exploring radical new designs for commercial planes

#85

Post by alistairSH »

AnimalMuppet wrote: post #58
gauravjain13 wrote: post #48

Earlier quoted context omitted.

True, but absolute bank angle would also matter (say endpoint of roll when roll acceleration is zero) because now there's a component of gravity pulling you sideways.

Not if the pilot did it right. The net force on you should always be directly toward the floor.

Even when the plane is tipped over at 15* (or whatever their max bank angle happens to be)? The floor is no longer directly underneath you.

Re: Engineers are exploring radical new designs for commercial planes

#86

Post by Symbiote »

horsawlarway wrote: post #28
blamazon wrote: post #22

Earlier quoted context omitted.

My experience as a frequent flyer is that First Class is the most likely cabin to have all windows closed for 100% of the flight. It's baffling to me, people will even keep closed the window facing New York on the approach to LaGuardia which should be a crime. Also Boston, Salt Lake, Hawaii, and really pretty much all places except like Dallas and Cleveland types totally perplex me when the window is closed and I'm n…

I see this more and more everywhere across the plane these days. I remember flying as a kid/teen and nearly every window was open during takeoff and touchdown. Last 3 to 5 years and almost every flight has had less than 10% of the windows open. I don't get it - I also want to see it. We're fucking flying, for god's sake.

At least in Europe having the blinds open (and the lights dimmed at night) is an airline requirement.

https://news.schiphol.com/why-do-the-window-blinds-have-to-b...

Re: Engineers are exploring radical new designs for commercial planes

#87

Post by ramesh31 »

jabl wrote: post #84
AlexandrB wrote: post #7

Earlier quoted context omitted.

Yup, I've been seeing these futuristic airplane concepts for most of my life, but commercial airframes seem to be converging to be more and more similar. Unusual elements like a third engine in the tail or horizontal stabilizers mounted above the rudder have largely disappeared. Given the thin margins in air travel, I suspect this is because this design is the most successful. It might be a local minimum, but when it…

Horizontal stabilizers above the rudder went away with the engines mounted on the body in the back, the reason for the high tail was to keep the elevators away from the jet blast of the engines. As to why create a design like that in the first place, I don't know. My understanding is that the 'engines under the wings' layout won because with the engines in the back the fuselage needs to be stronger (and thus heavier)…

A lot of the reasoning for business/regional jets maintaining the high tail mount engine layout is FOD avoidance. Operating out of shorter runways/smaller airports this becomes an issue.

Re: Engineers are exploring radical new designs for commercial planes

#88

Post by PicassoCTs »

Idea: How about a blended wing aircraft - that never has to land?

Fuel, Passengers, luggage and waste arrive via shuttles from the airport, while the plane circles slowly, docking in flight? Other passenger and personal on end of shift. Leave the same way, to other shuttle craft and the plane flies ever onward.

Only reason to ever land is maintenance which can not be performed mid flight.

In theory, a specialized shuttle might even switch an engine mid-flight if its constructed for it.

For the landings that are unavoidable other special shuttle-craft attach and bring along wheels or flotation packages.

Emergency landings? Just go with a set of parachutes, after arresting momentum. Or with flotation devices.

The resulting craft would be lighter, more economic, the downtime by its very nature would be lower.

Airports would not have to be rebuild, except for the spoke which harbors the albatrosses.

Re: Engineers are exploring radical new designs for commercial planes

#89

Post by jabl »

hotpotamus wrote: post #30
AlexandrB wrote: post #7

Earlier quoted context omitted.

Yup, I've been seeing these futuristic airplane concepts for most of my life, but commercial airframes seem to be converging to be more and more similar. Unusual elements like a third engine in the tail or horizontal stabilizers mounted above the rudder have largely disappeared. Given the thin margins in air travel, I suspect this is because this design is the most successful. It might be a local minimum, but when it…

My understanding is that tri-engine jetliners were actually more to fulfill a regulation than for engineering reasons. There are regulatory limits to how far a plane is allowed to fly on one engine called ETOPS - I forget what it really stands for, but the colloquial expression is: Engines Turn Or Passengers Swim. It used to be limited to around 2 hours I believe, meaning you've got a bit of time to divert and make a…

Yes, ETOPS ratings have been extended as engines have gotten more reliable.

Another factor is that we have learned to make bigger engines as well. So nowadays with two engines you can power a pretty big plane. And due to how turbine efficiency tends to scale with size, two big engines is more fuel efficient as well as saves on maintenance costs vs. having more but smaller engines.

For an extreme example, look at the B-52 with 8 engines. That was what was available back when the plane was designed, but nowadays the thrust from those 8 engines (about 600kN in total) can easily be exceeded by two modern large turbofans.

Re: Engineers are exploring radical new designs for commercial planes

#90

Post by tengbretson »

nervousvarun wrote: post #12
alexpotato wrote: post #5

Interesting historical note on the blended wing design: One of the main arguments against it was that designers weren't sure if people would be ok with sitting towards the center of the plane. The thought was that passengers wouldn't be comfortable without being able to at least see outside (even a little, looking at you 3/4/3 widebody planes). I mention this b/c there is a quote in Mary Roach's Flying to Mars. She m…

This "problem" goes away if you just have one of the feeds in the seat-back entertainment system be a wing mounted camera view no?

If that were true, why would the person be on the plane in the first place? Couldn't they just watch a movie of their destination or zoom call the person they were visiting from home?
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