Originally Posted by
whowhenwhy
It's worth noting that neither the demonstrator nor the Overture aircraft will utilise 'low boom' technologies currently being researched by NASA through their X59 program. Overture will be a 'traditonal' SST in the sense that it will boom.
The company originally aimed for M2+ but derated the performance requirement to M1.7 around 18-months or so ago. About the same time that Rolls Royce pulled out of their agreement with Boom as the engine development partner. It's hoped to eradicate some of the handling foibles associated with Concorde to allow the aircraft to be operated and managed in much the same way as any other airliner.
DARPA keep hoping that they can leverage civil funds to develop M2.2 x 5,200 mile range, (i.e. transpacific) at low (civilian) costs as opposed to high (military) costs and thereby open up large civilian volumes to get a virtuous circle of industrial development & application restarted for the benefit of the USA. Whilst the current paradigm has a fairly static commercial frontier (exemplified by Airbus, perhaps we can stil include Boeing) the competition can pull closer, i.e. China with Comac etc. This worris DARPA as they well know how exposed Boeing is in civil aerospace market, as is increasingly becoming publicly obvious.
In contrast pretty much every time realworld civilian money is at risk on the table they realise that the outcome is M1.7 x 4,250 mile (i.e. goodly transatlantic/etc) and that to push further requires acceptance of very steep cost & technology increases and commensurate programme risk, without a commensurate civilian return reward.
It is quite fun to watch DARPA/etc struggling with this. Repeatedly.