[cameldrv]

I don't think that the cabin size per se really made that much difference. Supersonic flight is always going to cost a lot more than subsonic, so you're targeting the segment that wants the speed/prestige of going Mach 2 and is willing to pay. There aren't that many of these people, and they tend to be sensitive to schedule, so you have to run the service fairly often. That means that you either run a small airplane or give away a lot of seats (even with 100 seats, at least towards the end, British Airways was giving free upgrades to Concorde for a large fraction of the seats).

I think that today the supersonic airliner market is still quite tough, because first class has gotten so good. For transatlantic, you only save four hours, and you can spend that sleeping fairly comfortably or using your computer with provided power and pretty good Wi-Fi.

Where there is more legitimate value is transpacific, where supersonic might shave 10 hours. However, due to the higher fuel burn, there's almost no way to avoid stopping for gas, which erodes the advantage both in time and comfort.

[jjk166]

Supercruise is actually more fuel efficient than subsonic flight. You're going faster but also through less dense air and the engine works more efficiently. The major impetus for the concorde was actually to save on fuel costs. The reason the concorde lost out was that it was using inefficient turbojets at the same time that subsonic airliners were adopting the much more efficient turbofans. Turbofans for supersonic flight wouldn't be developed until the 80s.

[TylerE]

This is wildly incorrect. Supersonic is much higher drag. A Concorde got 17 mpg/passenger in supercruise. A 737 gets 80-90.

What you are probably thinking of is that drag peaks in the transonic region (Mach 0.95-.99, say) but the Mach 0.85-.9 mostbairliners cruise at is much lower drag than either.

[jjk166]

Drag is higher, but jet engines are more efficient at higher speeds which compensates for the increased drag. Overall propulsive efficiency is at a minimum at mach 1, above that it starts increasing again. Beyond a certain point (supercruise) you get higher overall propulsive efficiency than at any subsonic point.

[TylerE]

Again incorrect! Look at the data. In what universe is having 12x the fuel burn (per unit of time) or 5x (by mile) “more efficient”.

A Supercuruising Concorde has higher fuel flow than a (much much larger) 747.

Your whole “engines more efficient at higher speed” argument is totally unsupported by facts. Supersonic flow is a major problem is jet engines. They have to use special very-high drag inlets to slow it down to subsonic velocity to actually combust.

The air being thinner doesn’t help, either. It’s basic chemistry... every unit of fuel you burn requires X units of oxygen. The density doesn’t really matter - except that denser air moving slower decelerates less and thus causes less drag.

[jjk166]

You're comparing apples and oranges. The concorde used turbojet engines with afterburners. That's 10 to 50x the fuel consumption of a comparable turbofan like the one a modern airliner uses. If you are using 5x the fuel with an engine that should be burning 10x the fuel, you must be using it in a way that is twice as efficient.

[TylerE]

No, that’s just dumb. BURNING MORE = LESS EFFICIENT

Vehicle A takes 10 gallons of fuel to move 4 passengers 500 miles.

Vehicle B takes 40 gallons of fuel to move 4 passengers 500 miles.

In what possible universe is vehicle B more fuel efficient than Vehicle A?

[ghaff]

Exactly. Even with modern first/business seating, subsonic trans-Pacific is still a long flight even from the West Coast even if the seating is comfortable and the food is good. But as I recall you need something like 2x the range of the Concorde even to fly a route like SFO-NRT. And, as you say, if you need to fuel up in Anchorage say, you lose a lot of the time advantage.

[cameldrv]

Yeah, and the problem is that there is a range death spiral, so you can't just scale up the plane. More range needs more fuel, which is more weight, so the efficiency goes down, so you need more fuel... I don't think that supersonic transpacific is really solvable with current technology. You either have to refuel mid-air or go suborbital or use a different fuel.

[ghaff]

And at some point, if you can make 20 or 24 hours of flying comfortable enough and maybe have good enough communication systems, who cares? (OK, there are a few people who want to go back and forth to Japan in the least time possible. But, let's get real. Air Force One isn't a supersonic jet.)

It's mostly a case of dialing in the space and price per passenger for the market. Given enough space and entertainment options--hey, live performances in the lounge!, celebrity chefs--very few of us really care that much about getting to a destination 12 hours faster.

[LargoLasskhyfv]

Just build something like https://en.wikipedia.org/wiki/Project_Habakkuk , only three times longer, put it where it is needed. done. Optionally combine with exquisite duty-free shop for the passengers stretching their legs while it is refueled. How hard can it be?

[jandrese]

Wouldn't a SFO-NRT flight do the layover in Hawaii? That seems much more direct, and in either case you're going to have to build the facilities to support the SST.

[ghaff]

Look at the great circle route. Hawaii is way to the south. (Although Anchorage isn't quite on the way either.) As I recall when my dad was flying to Japan a lot--sometimes on the company plane--there would sometimes be refueling stops in Anchorage though that may have been leaving from Michigan.