I think we could all speculate until the cows come home just how many SSTs could be built. To put my own two penny worth in here, personally I tend to agree with Steve that to justify the huge capital investment required, a hypersonic aircraft with just about antipodal range would be required. Here in the UK, the Reaction Engines Lapcat A2 project seems to be the way to go. Fueled with liquid hydrogen, making London to Sydney in just around 3 hours carrying THREE HUNDRED passenger. All this using four Scimatar hybrid engines. Contrast this proposal with the clumsy Airbus ZEHST effort that has to use THREE different types of engine for the flight cycle, carries only 100 passengers and won't be around (acording to them) for FORTY YEARS!!. Both imagination and practicalilty seem to be totally absent here.
It seems that the technology required for an HST already exists in the UK (the Scimitar engine is a deritive of the engine originally designed for HOTOL, thanks to the genius of Alan Bond and Bob Parkinson) but we need partners for obvious economic reasons, (probably not European), the will, and most of all, as I mentioned before, the vision to do great things again. In my humble opinion Lapcat A2 should be the true successor to Concorde. If only......
Best regards
Dude
