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Comment by LoSboccacc | Hacker News Reader

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.

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”the increased surface area”

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).

center fuel tanks (under the passengers) are common in commercial aviation

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