There are a number of non-starters here: 1. Efficiency counts for a lot in these aircraft, and it's absolutely possible to do better than the Olympus. In par

There are a number of non-starters here: 1. Efficiency counts for a lot in these aircraft, and it's absolutely possible to do better than the Olympus. In particular, high-temperature materials and engineering, along with combustor efficiency have evolved significantly since the Olympus era. Tenths of a percent are a big deal in subsonics, let alone supersonics. 2. Emissions are also a huge deal. Significant work would need to be done to clean up Olympus emissions. 3. Is the Olympus sized properly for the Boom design? Probably not. 4. We don't necessarily publicly know if Rolls offered to refurb and support these engines, but if they didn't, there are some very good reasons. Re-establishing a supply chain for these would be a really big deal, and in some cases not cost-competitive with a from-new design based on present-day supportability. 5. Supersonic boom noise being a non-issue is an absurd premise. It drastically affects your addressable market, period. 6. Time savings for a few critical needs as you cited are not going to be enough economic motivation to develop this system. 7. It's not that "China, Russia bad", it's that Chinese and Russian materials and manufacturing will not currently support the durability requirements for commercial viability of these hypothetical supersonic cruise engines you propose. You would have a lot of off-wing refurb time on such engines. Chinese engines don't have the performance, either. The case for anything Boom is developing is not really there.