Comment by Aurornis
21 hours ago
> XB-1 is the world’s first independently-developed supersonic jet, breaking the sound barrier for the first time in January, 2025. It was designed, built, and flown successfully by a team of just 50 people
This is a great headline and very impressive. However, it’s also somewhat puzzling to see the company spend so much investment money to build a small prototype plane that doesn’t resemble a commercial airliner in any way, break the sound barrier 6 times, retire it, and then conclude they’re on their way to delivering commercial supersonic passenger planes in five years
Boom Aero is one of those companies I want to see succeed, but everything I read about them tickles my vaporware senses. Snowing off a one-off prototype that doesn’t resemble the final product in any way (other than speed) is a classic sign of a company spending money to appeal to investors.
Retiring the plane after only a few flights is also a puzzling move. Wouldn’t they be making changes and collecting data as much as possible on their one prototype?
I work in aerospace and I don't find this development strategy unusual prima facie. I don't know if Boom is explicitly doing rapid spiral development, but this is what it would look like from the outside - a development vehicle that doesn't resemble the final vehicle design in many ways, but does have strategically selected commonality to validate and buy down risk on specific subsystems and operational concepts. They may be retiring XB-1 simply because they got the data they needed.
That being said, I share your skepticism of Boom as a company. As far as I know, they still don't have an engine for their production aircraft design.
Yeah.
The demonstrator was to validate some basic concepts they were promoting about being able to achieve supersonic flight without supersonic booms. It achieved that at relatively low cost, and gave them something to brag about, an indication of baseline competence at certifying airframes and possibly ticked off some investor boxes. There wasn't much more to be learned about large passenger jets using their intended custom engines from a small GEJ85 powered platform, so its not surprising they haven't gone to the expense of continuing to fly it. It's not going to be useful for most other stuff they might want to test, apart from perhaps their intended custom engines which are probably years away from being certified for flight tests, never mind hitting performance and reliability targets.
I wonder what kind of liability it would be to sell a one-off prototype plane like that. Guessing it would also have more value has a model in the lobby or on a pole outside headquarters one day than they would earn in selling it.
> There wasn't much more to be learned about large passenger jets using their intended custom engines from a small GEJ85 powered platform,
This is key to me.
I'm a layman in Aviation, so I'll unpack that.
The Boom XB-1 demonstrator (1) uses GEJ85: the General Electric J85 engines, as seen on military jets (2).
This is not the desired production jet's "Symphony" engine (3), which at a guess has to be both larger and more efficient?
So whatever is to be learned from the demonstrator, it doesn't tell us much about the final engine design.
In fact, all I know about this desired engine, is that Rolls-Royce isn't making it. (4)
Are they still planning to design the engines in-house? If they're making good progress, why are we hearing about how they're replacing excel as a design tool.
As I said in the other comment:
I'm not an expert, but this seems like the engine is on the critical path to success, and also high chance of failure. i.e. Without engines, they have nothing but a glider.
And if Rolls-Royce thinks that it's either not technically or commercially feasible, then who can do it?
1) https://en.wikipedia.org/wiki/Boom_XB-1
2) https://en.wikipedia.org/wiki/General_Electric_J85
3) https://en.wikipedia.org/wiki/Boom_Symphony
4) https://www.space.com/boom-supersonic-rolls-royce-engine-spl...
The HP.115 [1] and BAC 221 [2] were not exact scale replicas of Concorde.
[1] https://en.wikipedia.org/wiki/Handley_Page_HP.115 [2] https://en.wikipedia.org/wiki/Fairey_Delta_2#BAC_221
My take is that they felt like they were already pushing their luck with the prototype and didn't want to scare investors away when it inevitably crashed.
I share your skepticism, especially with their timeline. It has been some time since I looked at them closely, but they originally pitched developing their own supersonic capable turbofan to power their eventual production model. Especially with such a small team that seemed overly ambitious to me.
Hah.... in the back of my mind: announce they're going to crash it before the fly it.
"This flight we're validating our model by pushing the real world to the limit. It should explode about 38s into the test and crash. We've cleared the expected area"
Hopefully the plane is autonomous
The market for Boom is not commercial passenger flights. So much time is wasted with security, boarding, taxi-ing, waiting at the destination for a gate to unload, etc. that the flight speed is not a big deal. Existing commercial passenger jets could already go faster without going supersonic and save some time, but it doesn't matter. Even if you fly commercial passenger jets at the absolutely face-melting Mach 3.3 of the SR-71, you don't really save enough time to matter. The maximum speed in flight doesn't do anything to address ground delays.
> time is wasted with security, boarding, taxi-ing, waiting at the destination for a gate to unload, etc.
Airlines can optimise for this. Digital ID virtually eliminates security lines. Paying up for gate, t/o and landing spots takes care of the latter. There is a cost tradeoff for service in the airline business. An all-business airline flying Booms would almost necessarily have to pay up to negate these issues. (That or fly out of the FBO terminal.)
Airlines do not dictate airport security.
You cannot simply add gates to airports with even an infinite pile of money. It doesn't matter, unless you're going to make flights from nowhere to nowhere. Doesn't sound like a business strategy to me.
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That may be true for domestic coast-to-coast flights, but not for transoceanic ones across the Atlantic, or especially the Pacific, or north-south across hemispheres, that can take 8+ hours. Flight time is a higher portion of the total travel time in those cases, and seems like the main market for Boom, especially if they initially target Business Class flyers who do those kinds of trips regularly.
Boom XB-1 did 750 mph air speed. If I've got an 8 hour flight at 561 mph in an A380 that's a reduction to 5.984 hours when I move to the Boom XB-1. Who cares about saving 1.1 hours on a transatlantic flight. There is a reason why Concorde's cruise speed was 1,341 mph.
So when Boom makes a commercial airliner that hits 1000+ mph with the same availability and turnaround time as a typical passenger plane then I'll pay attention. Until then, it's for rich people who can buy their own plane.
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Not disagreeing with you at all.
What is the market for Boom?
I see you never flew from LAX to ICN.
I think part of it was that they were testing a new aerodynamic design that eliminates or minimizes sonic boom, so they can go supersonic over land almost immediately after takeoff, and operate over populated land routes. It makes sense to test that kind of thing with the smallest possible model first, then see if you can scale it up to passenger size without losing that quiet acceleration. Their timeline for doing that may be optimistic, but what they're doing makes sense.
The XB-1 doesn't have any boom reduction shaping. That's the NASA X-59, though that aircraft is pretty much a dead-end in that it's not scalable to a passenger configuration.
The XB-1 made use of an atmospheric trick to minimise boom propagation to ground level on one test flight, so well-known in fact that Concorde sometimes used it to accelerate as it coasted-out without an audible ground-level boom. Unfortunately that trick runs out at about M1.17.
It's also largely PR guff. The first privately-developed supersonic aircraft was the Northrop N-156F, forerunner of the F-5, that first flew in 1959. Funded entirely from company funds with no military contract. And it went supersonic in its first flight with no drama.
In fact the chase plane for the Boom XB-1 is a T-38, derived from the N-156F. It can outrun the XB-1.
I'm not sure how strictly privately developed the N-156F is given you could easily argue that reuse of design, knowledge and relationships from existing contracts saved them a lot of money.
Their immediate goal is to get the next round of funding. Viewed from this lense it makes a little more sense.