Boom Technology Overture M2.2 SST

[TomcatViP]

3D printed parts

 

[riggerrob]

We wonder whether they are using 3D Printing because of cost of materials (titanium) or whether they want to build components that are impossible (e.g. hollow) with conventional tooling.

 

[TomcatViP]

@riggerrob : Each assembly asks for components design, manufacturing drawings, detailled instructions and quality control.
3D printing helps to drive down cost canceling small elementary parts costs that otherwise would still need to be fully processed.
That also reduces iterating cost b/w R&D and production. For example when the CFD team makes a slight modification, the only thing that has to be incremented is the assembly itself. Not all the subcomponents.

In the past, machining was extensively used during prototyping to cut part nbr the same way.

It's still possible that during production they search for an alternative, looking for subcontractors that will produce the parts at a lower cost or better quality.

 

[TomcatViP]

Time to dust-off your CV, Boom is on the hunt for big names:

Boom Supersonic Begins 2021 with Addition of Senior Executives and New Board Members

/PRNewswire/ -- Boom Supersonic, the aerospace company building the world's fastest airliner, today announced that it has welcomed two new senior leaders to...

www.prnewswire.com

 

[Archibald]

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.

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...

 

[steelpillow]

The second generation of Boom will probably have electro-magnetic, plasma systems to steer air away from the compressor face.

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.

 

[AGS-1787]

Sukhoi also had a project or idea but it never got out, it kinda looked like an enlarged flanker with no tailerons.

 

[Zoo Tycoon]

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...

Over the last 20-30years I’ve attended quite a few lectures given by the genius’s from both sides the channel behind Concorde. A common theme is the choice of a pure turbojet behind a variable geometry inlet was instrumental to the project success. The reheat was only required for take off and breaching the Mach drag rise. I recall quite a bit of speculation as to if a slightly larger turbojet, combined with leading edge slats could be made to work without the reheat, which would reduce take off noise.

To go above Mach 2, Ted Talbot tended towards the Turbo ramjet of the SR71 as the best solution although he wouldn’t recommend a VG conical aerospike inlet.

 

[Archibald]

But if you use "straight turbojet" then both noise and fuel consumption kills you...
I remember many years ago Aerion (in a move I found quite desperate !) expressedly picked JT-8D for Aerion...because it was a very early turbofan thus pretty close from a turbojet !
Also, considering how dumb mankind tend to become, there is a small but real risk that we have forgotten how to make civilian turbojets since they faded away in the 70's...

Concorde engines were truly remarquable. Even more considering the fact they derived from the Olympus, a turbojet already with quite a long career before Concorde.
And Concorde B engine would have been even better - Olympus beyond 610 and up to 625, I found bits of information through Google books.

About intake ramps: note that Concorde had some very difficult moments between 1969 and 1976 with its ramps and their control systems. French pilots remember a memorable event where a ramp broke free... with the French Président Valérie Giscard d'Estaing onboard, returning from a meeting I can't remember where. The pilots very much exhausted their stock of adrenalin.

That's what happens when national prestige mandates turning a non-operational aircraft into a glamourous AF1. Pompidou did that, too, in the Azores in December 1971. Nixon was quite pissed off and nearly brought back Boeing SST from the grave out of frustration.

 

[Zoo Tycoon]

A straight turbojet’s fuel consumption can be ok, as Concorde proved with a cycle of around 40%. But achieving this was a massive effort and the thing became incredibly single point optimised. It was finely tuned for flights between the very Western Europe to very Eastern US seaboard and not much else;- Paris to New York could only be done by pressure filling the tanks, thus ballooning them out to gain that little bit more volume, towing it out to the runway to save taxing fuel burn, and routinely declaring Shannon as flight destination, only to then divert to JFK if fuel state at a mid point was satisfactory. This kind of stuff is no good for a business jet so the key is can you make the route. After all if you’re a billionaire with more money than you can spend in a lifetime, are you really worried about an extra ton or two of fuel?

Yes, Concorde’s intake ramps fell to pieces several times during flight test, the flying risk mitigation worked, the engineers looked at the data/broken bits, found the problems root cause and fixed it. It all cost money and took time. I think for niche technology areas such as these there’s now over reliance on computer modelling ability to solve these problems during the pre flying program phase. Musk knows this but most investors don’t. Also there’s an illusion that these niche technologies have benefited from 40years of progress, well no;- progress only happens when money is spent to put clever guys working problems and fixing broken bits. No one has spent a penny on this since the mid seventies. Worse than that and as you point out, a lot of the deep learning from the pre seventies has been lost. It’ll come back but only with money, time and broken bits.

A Turbojet Achilles heel is its noise;- Noise is fundamentally energetic air which is inherent in a high gas velocity jet. I reckon a few eVTOL guys are discovering you cannot change the laws of physics no matter how much of a billionaire’s fortune you spend.

 

[TomcatViP]

Philip Condit get one more chance to raise an SST out of the drawing board:

Boom Supersonic Adds Former Boeing CEO As Advisor - Simple Flying

Denver-based startup Boom Supersonic has made multiple high-profile additions to its advisory council this week. The company, which…

simpleflying.com

Go Phil !

 

[Grey Havoc]

From back in November:

A Supersonic Air Force One? - Blue Sky PIT News Site

Carnegie Mellon University grads involved in project to develop presidential jet faster than the speed of sound

blueskypit.com

“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.

 

[Grey Havoc]

View: https://www.youtube.com/watch?v=4p0fRlCHYyg

 

[LowObservable]

If I was invested in SBJs, I would not see Falcon 10X as good news. Dassault thinks it's a good investment of a lot of money to become a third producer of ultra-luxe 7500 nm-range subsonics that can avoid the seething throngs by landing on 6000-foot runways with minimal navaids.

 

[TomcatViP]

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.

 

[Archibald]

Philip Condit get one more chance to raise an SST out of the drawing board:

Boom Supersonic Adds Former Boeing CEO As Advisor - Simple Flying

Denver-based startup Boom Supersonic has made multiple high-profile additions to its advisory council this week. The company, which…

simpleflying.com

Go Phil !

I remember back in the days of the Sonic Cruiser, another Boeing man involved into it had the name of Walt Gillette. The joke was, back then Gillette had a brand of razors called "Mach 3".

Even the very serious Air&Cosmos couldn't resist the (lame) joke...
"With such a name, Walt Gillette should have worked on a Mach 3 airliner, but Boeing goal with Sonic Cruiser is more modest..." (facepalm)

 

[Archibald]

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.

Dassault has been a little burned with their SST atempt more than 20 years ago (see my posts above). Main problem remain the engine - one has to be created from zero, and that's a huge investment for a niche market of 500 to 1000 aircraft... Dassault don't want to try again. OR maybe they are waiting for the others to
a) pay for the engine, and then they will put it on a dusted off SSBJ
b) crash and burn for the same reasons as the SSBJ in 1999...

 

[Archibald]

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.

The laws of physics haven't changed since the late Chuck Yeager broke the sound barrier...

Above Mach 0.92 and up to mach 1.4 is a truly awful zone.
Supersonic flight is hard, but transonic flight is just horrible - economically at least.
Even Boeing couldn't pull a decent design a Mach 0.98 with the Sonic Cruiser... the economic case of flying a little faster never closed.

There are very good reasons Cessna stopped at Mach 0.92 with the Citation X, and also Convair with the CV-880, the 990 being even a little slower.

Coincidentally, just like the Cessna, Dassault new bizjet will cruise at mach 0.92... and no faster.

Compare a Sonic Cruiser at mach 0.98 with a CV-880 at mach 0.92: massive change in wind shape just to get closer from mach 1...

 

[steelpillow]

The optimum cruise speed is also complicated by altitude. The higher you go, the less your form and skin drag matter and the faster you fly to obtain the same lift and induced drag. But air temperature falls sharply up to around 35,000 ft and that is accompanied by a slowing in the speed of sound, i.e. Mach 1 at 35,000 ft is about 100 mph slower than Mach 1 at sea level. You have to get above 50,000 ft before the temperature and Mach 1 start rising again, and they don't rise as sharply as they fell. Your average airliner flies right in the low-Mach zone. So if you just want to scrounge a few more percent on the actual airspeed of your Mach 0.9X, it can pay to review your cruise altitude and wing area, rather than your Mach number.

The Mach 2 Concorde cruised at 60,000 ft for a reason, and I imagine that Boom will be aiming at least as high.

 

[Archibald]

Took me a long time to realize the sound barrier could vary from 1061 kph to 1235 kph... as you say, according to altitude and temperature... because temperature varies according to altitude ! Pretty weird to think about that fluctuation between 35 000 feet and 50 000 feet.
It just feels like the rocket equation applied to Earth: as if it wasn't tedious enough, plus chemical rockets, planet Earth makes it even more of a PITA !
Musk is kind of right when he says we are living on the "wrong" planet. For aerospace at least - as a human being I wouldn't swap it for Venus...

 

[TomcatViP]

Isa standard atmosphere.
Notice from 36 to 65kft (11 to 20km), T and Mach are cte.

 

[Archibald]

Very useful, thank you !

 

[jeffb]

Please excuse if this is a silly question but couldn't you build an SSBJ with both types of engine? Hi bypass engines for take off and climb and turbojets for the supersonic cruise phase? Could a bizjet design survive the resulting weight penalty?

 

[steelpillow]

Could a bizjet design survive the resulting weight penalty?

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.

Some motor gliders have folding propellers, which might be a way forward. But they'd surely be driven off the main supersonic jet engines as hybrid turboprops and not have extra ones for themselves alone. H'mm maybe I should patent that.

 

[Trident]

Tilt the lift fan on the STOVL F135 over by 90°...

 

[aonestudio]

https://twitter.com/i/web/status/1400406948546220036

View: https://twitter.com/boomaero/status/1400406948546220036

https://twitter.com/i/web/status/1400407090192125952

View: https://twitter.com/united/status/1400407090192125952

https://hub.united.com/2021-06-03-united-adding-supersonic-speeds-with-new-agreement-to-buy-aircraft-from-boom-supersonic-2653216403.html

 

[Archibald]

It will be interesting to see if Boom "bet" is paying or not. They chose to move away from the supersonic bizjet crowd and instead start the largest civilian supersonic aircraft since... Concorde ?
If that thing fly it will be rather unique in its market
- Concorde speed
- ERJ & CRJ passenger capacity (55 pax)
- but Bizjet range (4500 nm)

I wonder if there is a niche market hidden there ? Above 19 seats they can target airlines rather than businessmen, but 55 passengers is a rather odd number - see above, the only civilian jetliners left with that seating are the Embraers and Bombardiers; but I agree its the one and only thing they have in common.

How do they plan to fill those 55 seats ? some kind of "first class only aircraft" except at twice the speed ? I have suspicion the "Concorde nostalgia" is strong with that one.

If that work, then they could target the bizjet market " from above" a bit like Airbus and Boeing turning airliners into "ultra large bizjets" (A319CJ, Boeing BBJ) - 20 people in a space cut for 150, kind of.

A bizjet variant of the Boom would certainly offer a lot of room for 10 passengers in a cabin volume designed for 55...

 

[TomcatViP]

55 is a good average number for business seats in a transatlantic typical configuration.

 

[Archibald]

I think I guessed what they have a mind: trying to start again from the exact point where Concorde stopped back in 2000-2003.
That is
- New York to Paris / London and back (or a little farther into Europe thanks to better range)
- Trans-atlantic flights were tolerated back then for the antiquated Concorde, so what ?
- as long as they stick with that transatlantic flight profile, the boom is not an issue (no need for ugly low-boom designs)
- First-class business for the very rich, obviously - remember Air France and B.A flights ? champaign, caviar and hot stewardess.

Shrinking the Atlantic for the "upper class", Concorde style with an aircraft that, while half-smaller in Pax seating, will be 100 times more modern than Concorde at every level: noise, fuel consumption, range.

And they know a business case exists even if it stopped nearly 20 years ago (can't believe I'm typing this !): the said business case hold its ground for 25 years (1976-2001) with an aircraft that wasn't build for the job in the first place and thus while magnificent had some serious flaws (range, safety as tragically proven a day of July 2000, and noise).

Not the silliest business case, when you think about it !

 

[Josh_TN]

Having your travel time cut in half is the ultimate luxury, even if the seating was more cramped than biz class. I think the main problem will be locating a suitable engine for efficient super sonic speed.

 

[TomcatViP]

Seating is planned to be up to 50% less cramped (see how pitch seating is increased).


(from the link below)

 

[Flyaway]

 

[ADVANCEDBOY]

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.

 

[Archibald]

Perhaps they should try Aerion original JT8D idea. Early generation turbofans were faster because they derived from engines like J79. Noise and pollution however were less an issue back then...

 

[TomcatViP]

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.

Aerion promoted something on the opposite range of the design philosophy: expensively designed (at least that's what it should have been, hence, my opinion only, their last attempt to fish out something out of the design portfolio of Boeing and Lockheed), very complicated (see the design numerous Quirks (probably that Doug de Muro would have been their prototype customer)) and built inside purposely erected and grandiose manufacturing sites...

 

[Zoo Tycoon]

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.

Having seen some real world CFRP certified class 1 parts, I’m afraid I beg to differ. Although the promise is there, and indeed has always been there, to the best of my knowledge nobodies has been able to realise anything close to the publicity figures. A while back I saw a CFRP fuselage for a Biz jet which was to have been 20% lighter and cheaper than its aluminium equivalent. Only it didn’t turn out like that and not for the want of a lot of effort. The problem comes when you have to certify the thing you’re designing and the weight just keeps going in. Take for example conductivity, aluminium is and CFRP isn’t. So on the Ali fuse it’s inherently an earth return and lightening screened. But CRFP needs a remarkable amount of metal to provide the same functionality. When the magic -20% figure is banded about its a straightforward ratio of mass specific strength but the problem is designing something that works is anything but straightforward.

 

[Archibald]

Even Elon Musk dropped 21th Century composites for plain old steel, to build Starship...

 

[TomcatViP]

Nobody says that it's all about CFRP. For example if I take two large extruded or casted body panels and glue them together with high Mega Pascal glue, my part counts just dropped from a hundred to... 3 (two panels plus a tube of glue)...

 

[trose213]

Even Elon Musk dropped 21th Century composites for plain old steel, to build Starship...

That's due to stainless steel's unique properties.

 

[AeroFranz]

It's a bit frustrating to read posts that would make you believe that the workforce of aerospace companies is entirely made up of idiots.