Engineers are exploring radical new designs for commercial planes • Hacker News Board

Re: Engineers are exploring radical new designs for commercial planes

#51

Post by throw827474737 » Thu, Nov 10, 2022, 7:49 PM UTC

daveslash wrote: post #6

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…

Came to the comments to make nearly the exact same remark. I, too, remember seeing these in middle school in the 90s, as well as high school. Though, they weren't in my textbooks - but were in the supplemental "educational magazines" that the science teachers would supplement their coursework with, and "Popular Science" magazines that the school had in the library.

Dito, but before doubting myself.. radical new, wow.

Re: Engineers are exploring radical new designs for commercial planes

#52

Post by amelius » Thu, Nov 10, 2022, 7:49 PM UTC

nicktelford wrote: post #15

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…

A bigger problem with blended wing designs is actually for the people on the peripheral. When the plane banks, passengers further from the axis of rotation will feel a more significant change in their altitude. You literally feel like you're "falling", as the plane banks to your side. This also applies to existing aircraft, but the amount you drop/rise is limited by the your distance from the axis of rotation, which…

Banking isn't a problem in practice or your coffee wouldn't stay in your cup while standing on the table.

Re: Engineers are exploring radical new designs for commercial planes

#53

Post by shkkmo » Thu, Nov 10, 2022, 7:50 PM UTC

jcampbell1 wrote: post #16

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…

The main argument against it is that it increases fuel consumption. Plowing your cargo area through the air sideways is just idiotic. There is some crazy public belief that it is more fuel efficient because the public doesn’t understand physics. These things keep getting getting publicity because even Hacker News folks don’t get it. Long high aspect ratio wings and streamlined body are how you get fuel efficiency. Th…

Do you have any sources for this? My understanding is that hybrid wings reduce weight needed for structural components. Since fixed wings basically trade drag for lift, reducing weight can more than offset increases in profile/shape that increase drag.

https://www.technologyreview.com/2013/01/24/180345/hybrid-wi...

Re: Engineers are exploring radical new designs for commercial planes

#54

Post by inkcapmushroom » Thu, Nov 10, 2022, 7:53 PM UTC

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…

>speed, reliability, and safety

The article states that other designs are being looked at due to improvements in other areas, namely sustainability and suitability to alternate fuel sources. I would think that if you had a design that came close in reliability and safety, sacrificing speed for better efficiency would be a good tradeoff on many commercial flights with passengers or cargo.

Re: Engineers are exploring radical new designs for commercial planes

#55

Post by scarier » Thu, Nov 10, 2022, 7:53 PM UTC

jcampbell1 wrote: post #16

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…

The main argument against it is that it increases fuel consumption. Plowing your cargo area through the air sideways is just idiotic. There is some crazy public belief that it is more fuel efficient because the public doesn’t understand physics. These things keep getting getting publicity because even Hacker News folks don’t get it. Long high aspect ratio wings and streamlined body are how you get fuel efficiency. Th…

I mean, aerodynamic drag scales linearly with both Cd and A. It isn’t too far-fetched to think that you might be able to trade them off in a blended wing design and come out ahead by reducing interference drag and wetted surface area.

The pressure vessel problem is much more concerning to me—I can’t think of a way to solve it that wouldn’t massively increase weight and/or reduce usable space.

To be fair, the B2/737 comparison isn’t particularly fair—they were optimized for wildly different things, and only one design was significantly constrained by acquisition and operational costs.

Re: Engineers are exploring radical new designs for commercial planes

#56

Post by runarberg » Thu, Nov 10, 2022, 7:54 PM UTC

jcampbell1 wrote: post #16

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…

The main argument against it is that it increases fuel consumption. Plowing your cargo area through the air sideways is just idiotic. There is some crazy public belief that it is more fuel efficient because the public doesn’t understand physics. These things keep getting getting publicity because even Hacker News folks don’t get it. Long high aspect ratio wings and streamlined body are how you get fuel efficiency. Th…

I see. So this is why a flock of geese flies in a single file, rather then, say, a V shape.

Re: Engineers are exploring radical new designs for commercial planes

#57

Post by schiffern » Thu, Nov 10, 2022, 7:55 PM UTC

strongpigeon wrote: post #27

jcampbell1 wrote: post #16

Earlier quoted context omitted.

The main argument against it is that it increases fuel consumption. Plowing your cargo area through the air sideways is just idiotic. There is some crazy public belief that it is more fuel efficient because the public doesn’t understand physics. These things keep getting getting publicity because even Hacker News folks don’t get it. Long high aspect ratio wings and streamlined body are how you get fuel efficiency. Th…

You seem knowledgeable about this. Do you mind expanding on why these aren’t more efficient?

The problem is frontal area is higher, so more drag. Wetted area[1] is also much higher, so there's a lot of skin friction.

The advantages are (theoretically) lower structure mass per passenger. But airplane cabins are pressurized, and lightweight pressure vessels 'want' to be cylinders or spheres, not big flat boxes.

There's a aerospace engineering student who gave a thesis talk on the disadvantages of blended wing-body, and offers some possible solutions.[2]

[1] https://en.wikipedia.org/wiki/Wetted_area

[2] https://www.youtube.com/watch?v=IWBaddGG6z8

Re: Engineers are exploring radical new designs for commercial planes

#58

Post by AnimalMuppet » Thu, Nov 10, 2022, 7:56 PM UTC

gauravjain13 wrote: post #48

chrisBob wrote: post #23

Earlier quoted context omitted.

The issue isn't the bank angle exactly, it is the acceleration of the roll. Pilots will need to be careful not to throw people or drinks around, but I think it would be doable.

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.

Re: Engineers are exploring radical new designs for commercial planes

#59

Post by scarier » Thu, Nov 10, 2022, 7:56 PM UTC

nicktelford wrote: post #15

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…

A bigger problem with blended wing designs is actually for the people on the peripheral. When the plane banks, passengers further from the axis of rotation will feel a more significant change in their altitude. You literally feel like you're "falling", as the plane banks to your side. This also applies to existing aircraft, but the amount you drop/rise is limited by the your distance from the axis of rotation, which…

I mean, the rise of low-cost carriers has shown pretty clearly that passengers are willing to put up with a lot for cheaper tickets…

Re: Engineers are exploring radical new designs for commercial planes

#60

Post by runarberg » Thu, Nov 10, 2022, 7:58 PM UTC

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…

No. commercial airliners are only a solved problem if you ignore the climate crisis. There is no way you can run the current design on electricity during intercontinental travel. This is the problem that engineers are trying to solve with innovative and radical design changes.