All things being equal, it takes a lot more energy to slice through the air at Mach 2 than at Mach 0.85. But all things are not equal: Concorde flew about twice as high as regular subsonic planes. At that altitude, the air is about half as dense, so it takes less energy to move it out of the way.
In the end what matters is the lift to drag ratio and the speed ratio. In cruise mode, a regular commercial jet has a L/D ratio of about 17, and Concorde of 7 [1], i.e. about 2.4 lower. So each minute it spends cruising, Concorde will burn 2.4 times more fuel than a subsonic jet of equal mass. But Concorde flies faster, so it spends less time to cover the same distance. How much less? About 2/0.85 = 2.35. In other words, to cover the same distance Concorde burns about the same amount of fuel as a subsonic jet, while in cruise mode. Concorde’s fuel economy was horrible at takeoff though due to a triple whammy: L/D ratio of only 4, need to use the (very inefficient) afterburners, and the tyranny of the rocket equation.
But if someone can solve these issues, there is nothing that prevents a supersonic to be as fuel efficient as a subsonic jet.
This comes up periodically. The status does not seem to have changed in quite some time. They don't even have a scale prototype yet, much less anything like a full scale design. No place to build it, etc. At this point it's vaporware.
It's technically feasible of course but the claims are ridiculous. You obviously can't fly anywhere in the world in 4 hours at mach 2, and the $100 price tag is just stupid, which further solidifies the sentiment that it's just some kind of scammy attempt to gather funds. I bet even a simple calculation for fuel costs and zero profit margins won't give you the $100 promice even on high volume and "short" routes like NY-London.
And people overestimate how much someone's willing to pay in exchange of time. Even if you save 4 hours of flight (which is only a portion of the equation), you'd have to value your free time at least at $50/hour to pay even just $200 more. Some will, most won't. Europe is dominated by low cost airlines so I don't see the market for their product.
>"Either we fail or we change the world,"
Well this isn't a selfie filter, if you fail you kill lots of people.
[+] [-] throwaway00127|4 years ago|reply
It's a matter of physics; nothing we can do about it.
[+] [-] credit_guy|4 years ago|reply
All things being equal, it takes a lot more energy to slice through the air at Mach 2 than at Mach 0.85. But all things are not equal: Concorde flew about twice as high as regular subsonic planes. At that altitude, the air is about half as dense, so it takes less energy to move it out of the way.
In the end what matters is the lift to drag ratio and the speed ratio. In cruise mode, a regular commercial jet has a L/D ratio of about 17, and Concorde of 7 [1], i.e. about 2.4 lower. So each minute it spends cruising, Concorde will burn 2.4 times more fuel than a subsonic jet of equal mass. But Concorde flies faster, so it spends less time to cover the same distance. How much less? About 2/0.85 = 2.35. In other words, to cover the same distance Concorde burns about the same amount of fuel as a subsonic jet, while in cruise mode. Concorde’s fuel economy was horrible at takeoff though due to a triple whammy: L/D ratio of only 4, need to use the (very inefficient) afterburners, and the tyranny of the rocket equation.
But if someone can solve these issues, there is nothing that prevents a supersonic to be as fuel efficient as a subsonic jet.
[1] https://en.wikipedia.org/wiki/Lift-to-drag_ratio#Supersonic/...
[+] [-] rootusrootus|4 years ago|reply
[+] [-] mateo1|4 years ago|reply
And people overestimate how much someone's willing to pay in exchange of time. Even if you save 4 hours of flight (which is only a portion of the equation), you'd have to value your free time at least at $50/hour to pay even just $200 more. Some will, most won't. Europe is dominated by low cost airlines so I don't see the market for their product.
>"Either we fail or we change the world,"
Well this isn't a selfie filter, if you fail you kill lots of people.
[+] [-] towergratis|4 years ago|reply
[+] [-] lostlogin|4 years ago|reply
They have picked price and fast, so “good” has to go. Couldn’t that be something other than safety?
Thinking on the shittiest of airlines, could they go lower?
https://en.m.wikipedia.org/wiki/Project_management_triangle