AHC: Commercially Successful SST

As the subject suggests, how would a commercially successful SST come about. And I mean successful enough to warrant more then one generation of them, and preferably not require government subsidies to get them off the ground, at least no more then say the 747.

I know this is no small task. At least fuel costs and, probably, the issue of sonic booms will have to be dealt with. The sonic boom may or may not be a workable issue. The fuel costs are something else though. I have no idea how to keep them low enough for an SST to be a viable. Maybe less Arab-Israeli tensions?

Most lucrative airway in the world is North Atlantic. And no sonic boom problem over the ocean.

A little-known fact with the american SST is that they had the economic equation right.

250 passengers at Mach 2.7 was the right way.

Concorde's 140 passengers is too little.
But why Mach 2.7 ? Because airlines need to fly their airliners a certain number of rotation / hours per day to make money.

For supersonic airliners flying over North Atlantic it amounted to two rotation per day, hence Mach 2.7.

The ideal first generation SST would be a cross between Lockheed L-2000 (losing bidder)and Concorde B - the latter an evolution of Concorde without afterburner.

Rotations of a SST would be akin to this

Eight o'clock in the morning - take-off from Paris. Lands at New York at eleven o'clock in the morning.

PARIS 8 H > N.Y 11 H - one hour for overhaul and cleanup between flights

N.Y 12 H > PARIS 15 H

PARIS 16 H > 19 H N.Y

N.Y 20 H > 23 H Paris