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Comment by anarchy8 | Hacker News Reader

Why? That's a perfectly quantifiable claim.

I suspect the commenter is responding to “the world’s most advanced aircraft”, which does seem like a qualitative statement.

Yeah, it's meaningless but also irrelevant to the substance of the article.

The whole thing is a PR piece, calling the A350 the world's most advanced airplane must have satisfied some requirement for KLM.

They've sold/given/transferred patents to Airbus.

It doesn't say it's for the same number of passengers, equivalent travel time and distance traveled.

Fuel use is generally measured per distance traveled, so that part is implicit in the claim. The passenger capacity is talked about in the next paragraph:

> What’s more, the Flying-V will carry the same number of passengers – 314 in the standard configuration – and the same volume of cargo, 160m3.

I thought, specific to aviation, fuel efficiency was measured as a rate of time / power?

https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Propu...

Hmm... I've never heard of anyone mean thermodynamic efficiency when talking about fuel efficiency of a vehicle. Maybe people who design aircraft engines do?

See e.g:

https://en.wikipedia.org/wiki/Energy_efficiency_in_transpor

> The energy efficiency in transport is the useful travelled distance, of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means.

Ah, seems like then it's possibly a bit of column A and a bit of column B. I'll defer to you on the correction though, I was merely speaking from third-hand/watercooler type discussions about aviation as someone who is just a passive enthusiast of airplanes.

All airplanes are aerodynamic. There needs to be a mention of what exactly is happening to cause those fuel savings.

I highly doubt that those numbers are trustworthy considering how closely we are scraping fuel efficiency numbers, unless there is some performance metric they aren't mentioned that has degraded.

It has been known for a long time that flying wing designs are inherently more fuel efficient than typical passenger airline fuselage designs.

But in this extreme case of the fuselage being inside the wing and making it much thicker than typical and necessary, this isn't necessarily true, at least it's not obvious.

If this design actually provides the claimed results, connecting 2 such wings (one behind the other) with a long fuselage (i.e. >---> which would incur almost no additional drag and twice the lift) would be even better, no?

Think of it this way: A cylindrical fuselage provides no lift (except for the lift from its angle of attack flying obliquely through the air), only drag. If you can design the aircraft in such a way that all exterior surfaces contribute to lift, that would be ideal.

The "---" portion of your idea provides no lift, only drag.

The ideal flying wing is more efficient. The tradeoff to make a flying wing suitable for commercial aviation has historically made those efficiencies moot.

> All airplanes are aerodynamic.

There are exceptions.

https://www.spangdahlem.af.mil/News/Commentaries/Display/Art...

That plane was extremely aerodynamic, allowing high top speeds and high rates of acceleration. It wasn't easily controlled.

Good old starfighter. A common joke was that the best way to acquire one was to buy a plot of land and wait. One would come crashing sooner or later.

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