> Boom announced their own engine design last year but I'm assuming that's not ready
The complexity of designing an engine is comparable to that of designing an airframe.
The complexity of designing an engine is comparable to that of designing an airframe.
They will probably just iterate from an existing engine design rather than trying to re-invent one. Just because no one is manufacturing them doesn't mean the designs are not there to be used.
Time to mention Williams International
https://en.wikipedia.org/wiki/Williams_International
They're on light jets from Cirrus and Cessna. Boom probably needs something a bit larger - seems like an opportunity for a development program.
Then you have companies like Garrett/Honeywell that can make engines that output tens of thousands lbf like the TFE731 for mid-range jets and fighter jets. These can power big jets but not very fuel efficiently; that's the second tier.
The next tier up is the high bypass turbofans producing tens of thousands lbf used for commercial aviation and afterburner engines for last gen fighter aircraft are a completely different story. The GP is right there are only a few players in the game. Due to scaling laws, at this point it becomes less about the design and more about the metallurgy and material science. Magic like single crystal alloys are critical here and are very closely guarded secrets because the knowledge unlocks everything from ICBMs to gaseous centrifuges to nuclear reactors.
Edit: There are private groups that own supersonic aircraft and maintain them. EG:
https://en.wikipedia.org/wiki/Draken_International
They can get a hold of existing models and diagrams to produce their own copies since the patents have long since passed and been declassified for decades.
I think this is almost crucial. Airlines are not going to line up to buy non-renewable, fuel-guzzling, net CO2-gushing supersonic jets for use over the next couple decades.
Of course, this is nothing new: noise abatement effectively banned a whole lot of engines, too.