The engine that does this (except using a fixed inlet instead of a multi-chock inlet) is the GE Affinity. It flies between M0 and 1.4. The problem for the Boom project is its leaders who didn't know better put the bar at 10% faster than the Concorde, that had the luxury of a straight jet (and the consequential take-off noise). You can't handle the Ram drag at M2 unless you can limit the amount of air mass that enters the engine. It's physics, every engine designer knows about it. This is why the Tu-144 changed from a bypass engine to a straight jet during its development.https://paxex.aero/2020/07/boom-supersonic-rolls-royce-engine-partnership/
It is not a new technology engine, it is a new design engine. You’ve got knobs on an engine like bypass ratio and pressure ratio and they’re set in certain places for the 787 and you want to set them in different places for this airplane. It is moving the knobs, it is not let’s invent variable cycle or something that’s never been certified before.
Now, it's possible as the article says, that this will turn out to be impossible. But for right now, Boom definitely seems the possibility of something a lot less demanding that a new core and a variable cycle engine. A lot can be done with inlet and nacelle design, especially since they are really only trying to optimize for a single point performance, unlike the multiple points where military engines are trying to work. Having lots of excess thrust so they can take off at partial power seems like a simpler, if less efficient, solution.
The engine that does this (except using a fixed inlet instead of a multi-chock inlet) is the GE Affinity. It flies between M0 and 1.4. The problem for the Boom project is its leaders who didn't know better put the bar at 10% faster than the Concorde, that had the luxury of a straight jet (and the consequential take-off noise). You can't handle the Ram drag at M2 unless you can limit the amount of air mass that enters the engine. It's physics, every engine designer knows about it. This is why the Tu-144 changed from a bypass engine to a straight jet during its development.https://paxex.aero/2020/07/boom-supersonic-rolls-royce-engine-partnership/
It is not a new technology engine, it is a new design engine. You’ve got knobs on an engine like bypass ratio and pressure ratio and they’re set in certain places for the 787 and you want to set them in different places for this airplane. It is moving the knobs, it is not let’s invent variable cycle or something that’s never been certified before.
Now, it's possible as the article says, that this will turn out to be impossible. But for right now, Boom definitely seems the possibility of something a lot less demanding that a new core and a variable cycle engine. A lot can be done with inlet and nacelle design, especially since they are really only trying to optimize for a single point performance, unlike the multiple points where military engines are trying to work. Having lots of excess thrust so they can take off at partial power seems like a simpler, if less efficient, solution.
The engine is the key problem for an SST, especially if you want to go above M1.6. This is where fixed inlets don't work anymore and you have a real problem with normal cores, let alone a non-military low-pressure system. Boom has been at it for four years now and has made progress on every other account. On the engine side, they are still "studying possible solutions, and if an existing core can be used". The reason is what every serious engine designer knows, you can't solve it with a fixed design. Not today with the noise standard we have.
Speaking as a sometime professional electromagnetics engineer specialising (among other things) in plasma systems, I hate to disillusion you or anybody reading this thread, but that is just absurd sci-fi fantasy. There is so much about the real engineering which makes it grossly impracticable, I can't be bothered to start.The second generation of Boom will probably have electro-magnetic, plasma systems to steer air away from the compressor face.
The engine that does this (except using a fixed inlet instead of a multi-chock inlet) is the GE Affinity. It flies between M0 and 1.4. The problem for the Boom project is its leaders who didn't know better put the bar at 10% faster than the Concorde, that had the luxury of a straight jet (and the consequential take-off noise). You can't handle the Ram drag at M2 unless you can limit the amount of air mass that enters the engine. It's physics, every engine designer knows about it. This is why the Tu-144 changed from a bypass engine to a straight jet during its development.
The engine is the key problem for an SST, especially if you want to go above M1.6. This is where fixed inlets don't work anymore and you have a real problem with normal cores, let alone a non-military low-pressure system. Boom has been at it for four years now and has made progress on every other account. On the engine side, they are still "studying possible solutions, and if an existing core can be used". The reason is what every serious engine designer knows, you can't solve it with a fixed design. Not today with the noise standard we have.
A remarquable and extremely interesting post !
Let me add my 2cts to it... Dassault. SSBJ. 1999. I red a very good article back then which explained why Dassault, of all aerospace companies having one foot in supersonic combat aircraft, and the other foot, solidly into bizjets since 1963; couldn't get their SSBJ off the ground - off the drawing board.
Surprise, surprise: it was a matter of engine ! Dassault initially started the SSBJ hoping the M88 or F414 could be the basis of a supersonic business jet viable engine.
Well...
NO.
They found they were trapped into some kind of "catch 22" : the military engines failed on noise and fuel consumption and also... they are like Formula 1 engines. An exciting, but quite short life on the edge. As far as maintenance go, they are not at the level of civilian engines.
As for starting from a civilian core... Boeing or Airbus engines are not only way too large, but they are optimized for turbofan, subsonic cruise at Mach 0.85.
How about a custom build engine then ? technically, it could be done. Economically... it could not.
Even twenty years ago the SSBJ market was already narrow, perhaps some hundreds aircraft. 500 at best. And that was a decade before the "2010 supersonic bizjet craze" with Aerion and Boom and all the others.
Dassault concluded they could not afford the cost of a custom-build engine for the SSBJ.
So all three options to get a viable engine had failed - military, airliner, or custom-build.
Dassault tried for two years but, by 2001 they threw the towel. They haven't tried again. But their tri-jet SSBJ design is certainly stored on a computer somewhere...
“The United States Air Force is constantly looking for technological opportunities to disrupt the balance of our adversaries,” said Brigadier Gen. Ryan Britton, program executive officer for the Presidential & Executive Airlift Directorate, in a statement. “Boom is an example of the American ingenuity that drives the economy forward through technological advances.”
Along with Boom, the federal government contracted with startups Exosonic and Hermeus to develop supersonic aircraft for VIP transport, as well.
Philip Condit get one more chance to raise an SST out of the drawing board:
Go Phil !Boom Supersonic Adds Former Boeing CEO As Advisor
Denver-based startup Boom Supersonic has made multiple high-profile additions to its advisory council this week. The company, which…simpleflying.com
Hummm... Dassault won't move on that sector before it has proved itself stable and large enough for a full industrial to move on.
It's something to move a startup to work on an innovative product while taking risks from a rented office and working with contractors. It's another one to do that while also keeping your core business profitable.
Moreover, Dassault, like others big name, are probably confidents that once they will move on, the market will have a preference for brands.
It's a risk also. But financially less exposed than the one above.
Regarding the 10X, it's probably what the market want today with the segregation of first class and economy into business jets (taller (headroom), larger (shoulder), longer (ranged) and accessibility (short landing)).
The only drawback to me is the high power of their engines (as much as a 1980 fighter jet each !). But we live the space age where power has become a commodity. What matters obviously is specific consumption.
Hummm... Dassault won't move on that sector before it has proved itself stable and large enough for a full industrial to move on.
It's something to move a startup to work on an innovative product while taking risks from a rented office and working with contractors. It's another one to do that while also keeping your core business profitable.
Moreover, Dassault, like others big name, are probably confidents that once they will move on, the market will have a preference for brands.
It's a risk also. But financially less exposed than the one above.
Regarding the 10X, it's probably what the market want today with the segregation of first class and economy into business jets (taller (headroom), larger (shoulder), longer (ranged) and accessibility (short landing)).
The only drawback to me is the high power of their engines (as much as a 1980 fighter jet each !). But we live the space age where power has become a commodity. What matters obviously is specific consumption.
In a word, not economically, no. Apart from anything else the frontal area of the high-bypass fans would carry a vicious drag penalty in supersonic cruise. You'd need bigger cruise engines and a bigger aircraft to carry all the extra weight.Could a bizjet design survive the resulting weight penalty?
The revolution comes principally from the lightweight design: several dozen of engineers design an airframe that have a much less than 50% empty weight ratio with a parts count reduced by a order of magnitude. That airframe is then built by a 3rd or less of the manpower in non-proprietary manufacturing sites that are shutdown right after.Another pump and dump scheme. Or strip and flip. The passenger version is never going to be built. US hasn`t been able to build a commercial supersonic passenger aircraft since 60ies( and they never did), when they thought it could be done. Decade after decade it had never been a financially viable option. And it is not now. Let me repeat- I guarantee that the full scale passenger supersonic jet as advertised here will not be built. Ever.
The revolution comes principally from the lightweight design: several dozen of engineers design an airframe that have a much less than 50% empty weight ratio with a parts count reduced by a order of magnitude. That airframe is then built by a 3rd or less of the manpower in non-proprietary manufacturing sites that are shutdown right after.