It's almost as though I'm right when I say that making nouns of adjectives causes confusion. If we must have nouns from serverless, solar, and contactless, we're damn well going to get supersonic, too.
Anyone who has studied aerospace engineering in the last couple of decades was taught that the economics of supersonic travel are unworkable in an environment where fossil fuel energy costs what it does and is on the way out altogether. I was hoping Boom had cracked some constraint in that equation.
I havent spent much time digging into Booms plans before but its sort of wild that their secret weapon was just… nothing? We already know we have airframes that can achieve supersonic flight, so why wasnt the engine design the number one priority?
Noise is an issue for overland flying (which of course affects the economic viability of a supersonic aircraft).
But even if you assume there's a viable transatlantic market for supersonic flight, you probably can't charge all that huge a premium over business/first. If your premium has to be 2x to 3x, I doubt you have a market.
Handwaving away noise issues with supersonic flight over land gets you closer to something viable. But you still need economics that aren't that different from an all business-class subsonic. (And my understanding is that British Airways had trouble making all business work on the London to New York route.
>And my understanding is that British Airways had trouble making all business work on the London to New York route.
I don't know - the all-business class A318 service from London City to JFK ran from 2009 to 2020 and was up to two flights a day for a significant part of that time. I guess it was really Covid that killed it.
Their secret sauce, at least according to marketing was composite materials and high bypass turbofans, which combined could make a drastically more efficient plane than the Concorde.
I know nothing about Boom, but the "high bypass supersonic" thing raises the obvious question, how do they avoid the drag from the large (by definition) cross sectional area of the high-bypass fan?
> High bypass turbofans are the "engine" part we're talking about no body wanting to make for them. How saucy is an engine that doesn't exist?
The plane doesn't exist either, it was a plan.
> And composite materials like on the A350 and 787 have been around, see the A350 and 787
Their point of comparison is the Concorde. If they can make a plane that is significantly cheaper than the Concorde, thanks to the great tech that is now mainstream (composites, turbofans, CAD) but wasn't back then, it can be similar in cost to modern day business class, while still being supersonic. At least that was their marketing pitch, i don't see it taking off without an engine.
The economics of supersonic travel using a plane and engine designed in the 1960s (which had a massively upgraded newer version planned in the 1970-80s which was cancelled due to lack of interest) are unworkable. The Concorde was designed before CAD, high bypass turbofans, composite materials, so it isn't that easy to extrapolate to today.
Yes, but a modern CAD program can make the design faster (to design) and cheaper. Turbofans with high bypass ratios are more efficient than the engines the Concorde used.
Of course it would be less efficient than a subsonic jet, but they never claimed the opposite - the idea was for it to be faster, but not (much) more expensive than today's business class on subsonic jets.
>> "The faster you go in an atmosphere the more the atmosphere resists."
This is actually not even approximately true; like many aerodynamic phenomena, drag is super nonlinear in airspeed and not even monotonic, with a bunch of weird outcomes around mach 1. The first chapter of every aero textbook probably includes a variation of this famous chart [0], showing drag coefficient or sometimes drag force (estimated for some famous/classic airframe) as a function of mach number.
This is why prolonged supercruise can exist for airplanes without giant comical fuel tanks etc.
That said, your main point about CAD/physics definitely stands and is a good one; imho it would be unlikely to design and build e.g. a 10x better airplane than the Concorde today, even with all the fancy computers simulations etc.
You're conflating drag with drag coefficient. The plot you linked doesn't say anything about drag. Drag is more strongly proportional to speed than drag coefficient. That type of proportionality analysis is what's usually in the first chapter of aero textbooks.
Computers are great for marginal gains and saving labor costs, but they can't give a 10x improvement unless there's already a 9x improvement in materials and techniques. Small nit, but CAE is simulations, while CAD is just drafting.
Even if your drag coeficcient goes down from 0.3 to 0.25, doubling your velocity will still more than triple your fuel consumption over constant distance. Then the tradeoffs in airframe to make it not fall out of the sky in the transonic regime, then the loss of ISP from much lower bypass engines, then the smaller cabins, then carrying the extra fuel... you can carry far fewer passengers. Sure your drag went down substantially from mk 0.98, but noone is proposing doing a transonic trip because that would be insane.
You wind up using many times more energy per passenger, meaning you pretty much only have first class due to noone on a budget even considering paying 10x as much. Throw in the cost of SAF and you're looking at the price of a house per ticket in order to save 5 hours in the air from a total 15 hours travel/boarding/waiting time.
You are making two assumptions, one explicit and one implicit. That the cross-section area is constant (it’s not, it depends on the angle of attack, which is smaller at higher speeds) and that the air density is constant (it’s not, supersonic planes fly at much higher altitudes, where the air is thinner).
No. I was directly answering the assertion that the non-linearity of drag around the transonic regime somehow implied a supersonic craft would have lower drag than a subsonic one. The faster you move air to exert a force on yourself, the less energy efficient it is. KE=1/2 mv^2 and P=mv It is very simple physics.
You're making a similarly dishonest equivocation by carefully trying to frame the problem as if it were a mystery and the problem hadn't been reduced to lift/drag ratios 70 years ago. Which have an easily calculable upper bound for supersonic flight, by the way.
A supersonic craft has a much worse lift to drag ratio than a subsonic one. A supersonic craft even has a worse lift to drag ratio than the same supersonic craft at subsonic speed.
You can't even optimize your craft for that high altitude high speed regime because it still has to fly at lower speed and altitude and make it through the sound barrier without getting destroyed.
You will be using at least three times the fuel, so will need at least three times the ticket price. But that's not the only place a basic understanding of kinetic energy disqualifies the entire concept. Your engines/fans will also need at least double the effective exhaust velocity so their energy needs per unit of thrust will be doubled.
With this we can predict that all other things being equal, a supersonic craft will use about 6-10x the fuel per passenger mile as a subsonic one. A 747 has a bit over double the range and 4-6 times the passenger count as a concorde, so the naive approach got us in the ballpark.
Then for long haul flights (the only kind where supersonic will save time) existing airliners are almost half fuel by mass, which means you're in the regime of the rocket equation rather than having fuel scale linearly with distance. Then you can't offset business and first class with economy tickets and freight because noone is going to fly economy supersonic for 6-10x the cost or pay 6-10x the shipping for no perceptible time saving. With the previous in mind though, the supersonic craft is going to be limited to about 4 hours in the air before you start to lose passenger capacity to fuel. So it's not even great for long haul.
In short. Unless fuel prices drop dramatically ticket prices for a new supersonic craft would be commensurable with a new apartment for time savings of around 4 hours or at best 30% of the total door to door time.
At the altitude they used to fly at there wasn't much air resistance. I think it's more the acceleration and climb out phases when they are using the reheat (aka afterburner). Cruising at ~50-60000 feet, Concorde was pretty efficient, comparable fuel burn to a 747 from that era, but the engines were super inefficient in all the other phases of flight. I've heard it said that it used more fuel to taxi to the end of the runway at Heathrow than a modern A320 would use to fly London to Paris. (Someone else can google that to see if it's true! I can't be bothered.)
The taxiing was bad, but that wasn't the worst of it. To go from subsonic to mach 1.7 the Concorde used reheat ("afterburner") that just dumps fuel into the already hot exhaust. This is not particularly efficient. Then from 1.7 to mach 2 it didn't need reheat, and at mach 2 it was quite efficient of an engine design.
A 747 carries 500 passengers, Concorde carried 100. Your costs per seat mile are going to be at least 5x higher.
The Concorde engine was efficient at cruise - and pretty awful everywhere else. At cruise it was about 10% more efficient than a GE90. But the Concorde had 4 of them, and a 777 has 2 GE90s.
This is also why you don't see 4 engined planes anymore, except for the A380 and most people were hell bent on retiring during the pandemic until they couldn't get more 787s/A350s and the 777X is delayed.
The faster you go the higher in the atmosphere you can fly, therefore reducing drag (due to air being more rarefied). So it's not as simple as you're thinking.
High bypass turbofans have significance disadvantages in supersonic flight due to ram drag. It would require some additional breakthrough for that to make a difference.
The other stuff is incremental efficiencies, not enough to fundamentally change the very challenging math of supersonic flight efficiency.
Peeking at Boom's Wikipedia page - their 1/3 scale "technology demonstrator" test aircraft, which they originally said would fly in 2017, has been changed & pushed back & changed & pushed back... And it still has not managed to even taxi down a runway.
It doesn't much matter what is/isn't possible, or what could/couldn't be economical, if the company & engineers who say they are working to develop it...are not actually capable of shipping even a puny nerfed toy version of their supposed product.
My guess: the RR engineers concluded "maybe it's possible, but these idiots will never achieve it". Then quietly shared that with their colleagues at other engine makers.
My impression is that Boom was not looking to RR for engines for their demonstrator, but for their full-size production model. Those engines would have to be carefully designed & optimized for economic long-haul supersonic operation. (Vs. existing supersonic military jet engines are basically cost-no-object gas-guzzling hot rods.)
Boom did buy a current jet engine for the demonstrator, the GE J85. That engine is used on the T-38/F-5 so there are thousands of them on the market. The demonstrator is actually bad for Boom from a business analysis perspective because it is such an easy project that they have not been able to realize after hundreds of millions of dollars.
The "small supersonic aircraft" which is what the XB-1 is, is a solved problem. "Advanced composites" is irrelevant, any aerospace firm can make a supersonic-capable aircraft out of "advanced composites". Scaled Composites build SpaceShipOne in three years with about a hundred people in a hangar.
But Boom hasn't gotten the XB-1 into the air after five years and tons more cash.
Building a new supersonic airframe: easy
Building a new supersonic jet engine: hard
Literally and actually with no exceptions every single modest-sized aerospace firm can build a supersonic airframe. That problem is solved. Tens, if not hundreds, of thousands of supersonic aircraft have been built and many of them are capable of carrying passengers.
This is not an exaggeration. My employer isn't even in the supersonic aircraft business and we could build and fly a supersonic aircraft if some executive got a wild hair up his butt, in less time and money than Boom. Tiny and embargoed firms in a variety of foreign countries with small or non-existent aerospace industrial bases have done it.
The research into the aerodynamics and stresses on supersonic airframes is done.
Engines are hard. There are only a handful of companies with the expertise and cash needed to develop a supersonic jet engine, especially one that can super cruise.
Boom is saying "yah we're gonna build a supersonic passenger jet, uhhh, don't worry about the engine we'll figure that out later, give cash please".
What Boom is doing is functionally equivalent to an EV startup saying "Yeah we're going to design a car that can go 300mph (easy, individuals {Bob Dauernheim, for one} in garages have done it) that is powered by electric motors (hard) that don't exist yet and that someone else will design" and then getting hundreds of millions of dollars to design the chassis while negotiating with motor and battery suppliers to do the R&D into the hard bit at their own risk with the promise of profits from future sales to all of the people who want a 300mph EV.
If passenger density was comparable to a typical airliner, an intercontinental E2E flight should be roughly comparable to a subsonic flight. The supersonic flight would be substantially worse. Rockets have the advantage that they very rapidly get out of the dense part of the atmosphere.
In reality a Starship flight would probably sell few very expensive seats instead; just like Boom's aircraft only has 50 seats. Which would make it worse than subsonic flights in terms of fuel used, but still competitive with supersonic.
Starship's payload volume is around 1000 m ^3, which should be about the same as an A380 interior volume.
For a flight time between 20 (minimum) and 40 minutes (maximum) to anywhere on earth, this volume could comfortably fit 1000 passengers per flight.
At 2 or 3 times the price of a regular ticket, their offer would be a direct competitor against business class tickets, if they can reduce enough the risk, and handle logistics of rapid reuse.
Should be much better, you spend most of the time coasting and most of your acceleration in very thin atmosphere, vs a plane that has to cruise down in the soup.
Also, starship has more pressurized volume than a 747. You can fit a lot of people.
And don't forget the required pressure suits. You can't just to use simple masks like in airplanes, since cabin pressure loss at heights beyond 25km would make breathing using just oxygen masks impossible.
A "short boat ride" you say... Current exclusion zones and logistical requirements suggest otherwise.
Realistically, P2P using giant rockets is a nothing but a pipe dream. Just straight forward things like weather proof this. The latest F9 launch had to be scrubbed two times due to unfavourable weather at the launch site, for example.
Now multiply that just that weather-risk by two, since the landing site also requires good conditions at the same time.
Then there's the "little things" like airspace closures, launch permissions, boarding procedures, the requirement for personal pressure suits (simple masks won't do in case of cabin pressure loss), etc.
The idea sounds so easy on paper, but there's a lot of good reasons that in over 60 years of crewed space flight, the idea hasn't even been demonstrated.
F9's fineness ratio makes it very sensitive to weather. Soyuz rockets can launch in blizzards.
Starship should be weather insensitive as well.
Now for the launch platform, it will have to be built about 30km from shore, and could be accessed by high speed train, the travel time would be 15-20 minutes from the shore
Don't confuse satellite launches with crewed launches. Losing a satellite due to a failed launch is no big deal, risking the lives of potentially hundreds of passengers is a different story entirely.
Sorry, it took me a bit to reply to you on this censorship laden bullshit “you’re replying to fast by posting more than 3 times a day” website.
Fuck dang, time to cycle residential proxies.
That said, see sibling comments about fineness. In addition to being fine in the shiny variety, starship is a portly fellow. It will be able to land in anything less than a hurricane.
This basically boils down to ESG. With companies like Blackrock owned Morningstar rating companies on that kind of criteria, there's no way that a company is going to put themselves in a position to be providing engines for this sort of thing.
Yeah but doing important drug deals on zoom is a major no-no.
Seriously, we know for a fact that all internet communications have been completely compromised for a long time. If they have ever been safe. It makes plenty of sense if money is no object and certain things have to be discussed. That said, it's a massive waste. I wonder what happened to Musk's idea to have rockets fill that niche
Curve25519, ChaCha20, and plenty of other cryptographic primitives haven't been comprised (and there's a good chance they never will be). You can absolutely communicate over the internet without others reading your messages.
It has been a dumb idea from the start. In a nutshell, making the whole process secure to acceptable levels would slow things down to the point where it's the same time as a regular plane flight. Yet it would cost orders of magnitude more.
Edit: I'm commenting on Musk's rocket travel proposal
SpaceX announced the plan for cross-world rocket flights cheaper than a business class ticket in 2018, by 2028, and Musk doubled down on the timeframe in an interview in 2020. Boom doesnt have a chance of earning back its investment if it will only be able to operate for a few years before Musk comes through on his aggressive timeline. Passengers will need to be fitted for spacesuits and there is no launch abort system.
Musk’s service will never fly, it’s pure fantasy. There’s no way that governments are going to allow an ICBM through their airspace just because some businessman is willing to risk his life to get to a meeting on time. To say nothing of the environmental costs.
Yeah. People are obviously getting back to face-to-face meetings. But I'd at least like to think that jetting from NYC to London just to sign some documents or to shake hands on a deal over lunch is something we'll see less of.
If you're doing a longer road tour anyway, saving a few hours on the transatlantic legs doesn't really buy you a whole lot.
You save more time by flying a 'private plane' (with checking/security lines + it will fly at your preferred time) than flying a commercial supersonic jet
Oh this is absolutely another problem for supersonic time savings.
Supersonic flight over the continents is problematic, but not everyone lives on a coast. So many customers will have to take slow planes to aggregation hubs, which can easily add hours to an itinerary. Edit: And the aggregation hubs may not all serve the same destinations. Could easily see SF residents having to fly commercial to NYC to catch a Boom to London, even though there might be a Boom that flies SF-Tokyo.
Once you add up the fixed time costs of getting to the airport, security, flying to a supersonic hub, the percentage of time that can potentially be shaved off the itinerary dwindles.
Boom unfortunately does not have the range to make it transpacific nonstop either. Which is kind of a shame because 10+ hour Asia-NA flights would be a great nut to crack in terms of halving travel times.
I flew business multiple times, Frankfurt-SF (~14h), and it's a breeze if you can lie down and sleep. Not even boring. Jet lag is way worse than the flight itself.
JFK - HKG is 17h30. Even SFO to HKG is 12h30, and those are two cities on the coast in a middle position. (I'd rather pick Shanghai as a comparison but there are no direct flights at this time due to zero COVID so the info is hard to get.)
The longest scheduled flight right now is probably SIN to JFK at 18h30m. Qantas wants to do a 20h JFK-SYD route.
The point was that you get to bypass a lot of the usual airport routine with private and also have greater flexibility when you fly. (Though flight plans still need to be filed and airport runways can still be congested.)
And, yes, a private supersonic would be even faster but then it becomes even more of a question about the size of the market.
Hmm I’m not so sure. My sister used to be a project manager at an Enterprise software company. She lives in NL and was put on a project in Prague at some point. Think 10-20 engineers setting up some product at the customer site, ie it was worth tens of millions (licenses + consultancy fees).
After months of mostly living in a hotel, she got tired of it, told he boss she wanted to go back to basketball training in her home town so wanted a different project.
Her boss solved it by flying her to Prague and back every week so she could make basketball training on Thursday nights.
I think that if there was supersonic flight they’d happily have found her a project in New York next and foot the bill, twice a week, just so she could keep going to basketball training and still run the project in person.
Honestly that sounds exactly like the type of "small niche" of customers that GP talks about. There can't be too many megacorps willing to do this and I bet most project managers wouldn't go for it either.
Btw, that sounds like the worst solution your sister could have agreed to. She was tired of living in a hotel but is willing to keep living in an hotel and also fly back and forth between Prague and Amsterdam every week?
This is a dying niche (source: have worked in Enterprise software for 20 years, used to live on a plane like your sister) that is largely moving to cloud deployments run by remote teams (those teams may themselves be co-located). The other prevalent model is opening a satellite office on the customer's continent, so that staff can be semi-local with shorter commutes.
And even if she was a good representative, look at the ratio: 10-20 engineers to 1 project manager flying supersonic. I'm not sure that's a great market niche.
> if there was supersonic flight they’d happily have found her a project in New York next and foot the bill, twice a week
I do have to laugh at this, because there are numerous consultants who do this now, using our current planes.
Edit: Amsterdam<->NYC 4x monthly for business/first class (equivalent to Boom pricing) looks like it will shake out in the range of $30k monthly in airline tickets. Very few employees in a company will justify that kind of travel spend. (And still not fly on a corporate jet.)
Transatlantic is a bit of a special case as most corporate jets don’t have the range for that, without doing something extreme like going way out of their way and stopping in Iceland (and thus being even slower than commercial)
'Million miler' or 2M status meant something different twenty years ago than now. Now it means the person is unable to use communication tech and instead subjects themselves to invasive screening at airports.
It was unavoidable for some people twenty years ago. Now it is a badge of stupid.
Indeed. I never got to 2x/week, but in the late 1980s I was traveling about seven days a month. I switched jobs, and for a while would see jets heading in to the local airport and think how grateful I was not be on them.
I am not sure if you travel cross continent a lot. I live in India and for me to travel to the US for work takes 24 hours of continuous travel over multiple flights. If I can cut it down to 12 hrs, that would be a game changer for me.
This is a classic case of "supersonic is not the answer." Depending on the city pair, this is a ~15h nonstop on a commercial flight today. If an airline started serving your city pair, you would immediately save 9 hours.
Also keep in mind that supersonic won't help beyond the coasts due to noise/overflight rules that would require flights to slow down over the continents anyway.
One example of this is Los Angeles-Delhi. Probably possible with existing planes but would require cargo or passenger limits, which would make the route not profitable. No American airline is interested, given the connections available elsewhere, and Air India's (they've expressed interest in this pair before) habit of running routes at big losses will probably start to reduce now that they're privately owned. Airlines are perfectly happy to add more hops to your trip.
If there was a supersonic LAX-Singapore (I doubt India would allow supersonic planes), at least the longest leg of the trip is mostly over ocean, supersonic, and the Singapore-DEL flight is just a normal one.
Looks like United was running flights from SFO nonstop to Delhi until Russia closed their airspace to US flights. Looking at the list of longest nonstops, a hypothetical LA-Delhi, assuming usage of Russian airspace, flight would fit within the range of a couple of aircraft.
The JFK-Singapore direct would still be hundreds of km longer.
LAX-SIN is still more than 2x the best projected range of this plane.... Flying supersonic really guzzles gas, you're carrying gas to carry gas. Maybe if Boom added mid air refueling... but they'd have to slow down for an hour to do it.
But Supersonic is indeed AN answer. Delhi-Dubai takes 4 hrs. and if Dubai to NY could be done in 4 hours, I would very much prefer to buy that ticket - even if the fare prices are twice that of normal business class. Dubai-NY is a crowded route and there are plenty of very rich professionals who can take it on a regular basis.
And even for personal flights - considering that I have to travel only once a year between India and the US, I would very much welcome this option.
The current 24 hour long journey is just too brutal, and often time constraints mean that I can't break the journey into small hops over 3-4 days. And I shudder taking my family with me on such trips, given how much of a stress it causes.
Today's state of the art is what? a 2-hour flight from Delhi to Mumbai, then a 16-hour nonstop from Mumbai to Newark? 18 hours in the air. Versus a hypothetical 4 hour Delha-Dubai then 5 hour Dubai-NY for 9 hours total in the air.
So $1,100 for today vs $7,000 for supersonic (using business class fares as a proxy) to save 9 hours of flight time. My assertion is that there's relatively few people on any given route who have enough money and fly that route enough to make this a viable niche outside of a very limited set of routes.
> I shudder taking my family with me on such trips
I hear you on that! But also the notion of spending $7k for each of us is somehow worse.
Per Boom's website, they are targeting price points that would let businesses economically sell seats at normal business class fares. However, knowing airlines, I would be surprised if they sold tickets for less than (say) 1.5x the highest subsonic fare for the route.
Using the example above, that would put supersonic flights in the range of 10x economy, which feels about right for airline pricing. (At least until there are tons of supersonic flights to push down prices.)
DXB-JFK is over land almost 50% of the route, it will never make sense for Boom or anyone - you can fly subsonic to London and transfer to supersonic to shave a few hours off though - though shave off 45-60 minutes for transit buffer.
If they actually can get 4,250nm of usable range, you might be able to do something in Japan to SEA or maybe SFO, and that routing would make more sense probably.
But this is really really unlikely to ever fly - the physics and economics are so stacked against this until something really tectonic happens with how we store and use energy... but like not fossil fuels. It would need to be something that borders on "free", like if fusion existed, and was safe, easy and light.
The Concord practically defines "small niche." Entirely possible it made money, but less money than could be made charging Concorde fares for First Class seats on normal flights.
When you buy a plane for 1 pound/franc, and don't have to worry about paying any development or manufacturing costs, you should be able to make money. If you can't, it's a serious problem!
And I'm not sure that Air France was actually making money. The story I heard was that AF wanted to retire their fleet after the accident, because they hadn't made money on it. BA balked because they were making money but having to pay full costs of fleet maintenance equipment, rather than splitting those with AF, changed the numbers enough that BA would have lost money, so the whole fleet was retired.
> Rich/"important" enough to pay for business-class transcontinental flights
Business class from east to west (via emirates and qatar for example) can sometimes (more often pre-covid) be grabbed for $1000 above an economy ticket. The departing US business class ticket costs often seem very specific to our market. A lot of people on HN can bump up their tickets while flying outside the country even just for vacations.
The backlash only matters if you get caught. Low key charter is a luxury good. I've never done it, but I know a lot of younger co-workers who have "splurged" on chartering for destination vacations/weddings/etc. at $10k each or whatever.
That kind of diffuse luxe stuff will not get cleaned up by pushback.
Even if there was a business here, it is not a good _startup business_.
Startups, especially if any hardware is involved, mostly need to be companies that are leveraging an entire stack of off-the-shelf, on-the-market, mostly commodity components into a product or solution which is mostly, at least at first, a packaging exercise on the HW side and perhaps novel go to market (AAS, for example), UI/UX, etc. experience on the SW and solution side. Very few startups are going to work outside of these guide rails, and even when they do the exit/invested is pretty poor at this point and has been getting poorer for at least 20 years. You get to tweak the last 5-10% of your tech stack in HW and had better have something really compelling as a result.
There's probably _business_ in SST but between the tech stack, the dependencies, and just plain practical business issues like liability/etc. not a business that you get to as a startup.
By this token, we should never see fission and fusion startups. Yet NuScale is quite successful. They are now a publicly listed company (ticker SMR) with a market cap of more than half a billion dollars. Not quite a unicorn yet, but then they did not ship any reactor either. Once they do, their market cap will shoot up. Helion is the startup that Sam Altman is so happy to talk about (e.g. [1]). Maybe it will not succeed. Scratch that, most likely it will not succeed. But if it has a 1% chance to succeed, then Sam will see his investment go up by a factor of 10000, so in expected value it is a winner.
Boom is just the same. The chance it will fail is about 90%. But if it does succeed, it will return much, much more than 10x to their early investors.
You had it right at the first sentence. Becoming publicly listed at a time when total garbage was getting on the market via SPACs (which is what NuScale did) is not validation of anything.
Boom has a 99.999% chance of failing. Without an engine lined up, they aren't even in the business they're claiming they are, and haven't been for years.
It so happens that NuScale went public exactly 6 months ago. Since then S&P500 went down more than 15% while NuScale went up more than 30%.
As for Boom, I have to admit, they have a problem.
The problem is that companies like GE that make jet engines, can make quite some nice profits by selling to the military. The XA100 [1] most likely exceeds any requirements Boom can only dream of, but being military technology, it is off limits for them. If GE lands a fat contract to provide engines for the F35, then they'll sell thousands of engines, with very little uncertainty. Getting involved with Boom will only complicate their life. If they don't fully compartmentalize the two departments, they can get in trouble. If they do, there's no synergy. Plus, the doubts will always be there that they leak military technology to the civilian side.
That's a shame. GE makes some incredible jet engines.
Maybe the war in Ukraine will end and one day Putin won't be president anymore, and Russia won't be under sanctions. Then Boom could buy an engine from Saturn, such as [2], the engine that powers various Sukhois. The military-civilian tension will still be there, but Russia will need to export things, so maybe a deal could be made.
A military engine is unlikely to be the answer for Boom. They just won't be cost effective.
The math for efficiency and maintenance is just different for sovereign governments, maybe a derivative could be made more efficient with less maintenance required.
Fighter jets require like 6 hours of maintenance for every hour of flight - sure, it's not just the engines, but it's a big part of it.
The real problem boom has is the number of viable flights is _very_ low - really just the ones Concorde flew (NY-LON, NY-PAR), and Concorde never made money.
A couple comments up someone claimed DXB-NYC being a route - more than half of the great circle route is over land, and it's more than 50% longer than the rosy projections Boom put out. Realistically, they'll be lucky if they're within 10% of their stated range. But of course, not without an engine.
We also didn't care about being green back during the Concorde - but Supersonic flights will likely be 5x-10x worse on a per passenger seat mile basis for emissions. Really hard to get around wind resistance being a square of velocity.
> Really hard to get around wind resistance being a square of velocity.
That's a common misunderstanding. Very common.
In cruise mode Concorde was as efficient as a Boeing 747.
When you go faster, you do two things: 1. reduce the angle of attack, 2. fly higher. Concorde was flying twice as high as subsonic jets. The end result is that you still get increased drag, but much less than the square (or cube) of velocity would suggest.
Ok, but increased drag it is, right? Right, but you go faster. If your drag goes up by a factor of 2, but your speed by a factor of 4, then in the end you burn less fuel. It so happens that Concorde's drag went up virtually by the same factor as its speed.
The problem with Concorde was that it was horrible aerodynamics during the takeoff stage. At that point the plane is the heaviest (its has full fuel tanks), so the problem was compounded by some sort of "tyranny of the rocket equation".
Can Boom solve this problem? My guess is that this was their pitch to investors. In the 50+ years since Concorde was designed, both computers and computational fluid dynamics experienced huge advances. The computer I'm writing this on has probably performed more flops since I started writing this comment than the entire computational modeling for Concorde in its decade-long work.
As for military engines (and their maintenance) being expensive. F-35 is like a Formula 1 car, as USAF general Charles Brown once said. Its engines are pushed to the limit on a constant basis. A commercial jet is very different. It does not need to pull huge Gs. Its trajectory is very, very predictable. I'm sure a company like GE could make a very cost efficient jet engine for Boom. It's just that they have much better ROI if they build engines for F-35.
> In cruise mode Concorde was as efficient as a Boeing 747.
Yes - a plane that carries 550 passengers vs a plane carrying 100.
Also, the game has changed a fair bit - no one is building 4 engined planes anymore - because while it was about as efficient as a 747, it’s going to be less than half as efficient as a 777. That carries 400 passengers.
The wiki page I linked quotes an L/D ratio for Concorde (in cruise mode) of 7 to 7.5 and for Boeing 747 of 15.3 to 17.7. Taking the mid-points of 7.25 and 16.5 we get that the L/D ratio for Boeing is 2.275 higher than of Concorde. But Concorde's speed was 2.41 times higher than Boeing's (Mach 2.05 vs 0.85).
There are 2 things to go from here to actual fuel per passenger*mile. How much fuel do you need to produce the same thrust, and how much aircraft do you need to carry a passenger. On both counts, supersonic airplanes have a problem: supersonic engines have a lower bypass ratio, so they are inherently less efficient, and supersonic planes need to be sturdier, and therefore heavier than subsonic ones.
These problems are hard.
But the difficulty of building a supersonic aircraft does not come from the air resistance being the square of the speed.
By the way, the L/D ratio decreases with the speed, but it does not tend to zero in the limit. This fact is actually stunning, if you think of it. As the speed goes up, at some point the L/D ratio stops decreasing, so you end up burning significantly less fuel per mile. That's the reason some militarizes invest in hypersonic missiles: they have much longer range than their size alone would make you think.
Lift to drag is interesting - but without dividing by seats or tons is incomplete. You’re not really measuring work being done (actually transporting goods or people).
These problems are hard.
Lift induced drag goes down as velocity decreases, parasitic drag goes up as velocity increases. There’s there’s wave drag to contend with. Yes there’s weird places where going faster is helpful, but I doubt we’re going to see real net efficiency gains going faster than Mach .8-9 anytime soon.
So, can Boom compete with subsonic airplanes. Where can they have an edge?
They have two actually:
1. they are a startup. Boeing and Airbus are old and ossified. Smaller manufacturers are probably not as ossified, but they already have a niche, so their risk appetite is different: they prefer to put their research money to work towards incrementally improving their current designs. Boom is in a life and death situation, they have a huge fire under their feet, and so they'll get more research done for the same amount of dollars
2. Clean slate. All current civilian airplanes are cylinders with flat wings. It's a proven formula. Manufacturers don't want to move too much from a proven formula. But Boom does not have this type of fetters. In particular, they can design a body that follow the Whitcomb area rule [1]. Which is what they are actually doing [2]:
Contoured fuselage: According to the principle of area-ruling, Overture’s fuselage has a larger diameter toward the front of the aircraft and a smaller diameter toward the rear. Boom has applied this design technique to minimize drag and maximize fuel efficiency at supersonic speeds.
In addition to that, Boom plans to use wings that are not flat (they call them gullwings). Presumably, they know what they are doing, they say they used 26 million-core hours of compute between the first and the second iteration of their Ouverture.
Will the manufacturing costs explode? I guess they should be higher than for traditional geometries. But that works to their advantage: it keeps the current manufacturers from trying these non-standard geometries, and keeps them in a local optimum from which they find it harder to move. But it won't be a dealbreaker for a premium aircraft. That's basically the Tesla Roadster gameplan.
Even if there was a business case, the bigger issue with Concorde was the sonic boom. This seriously limits the number of routes for any supersonic plane, essentially limiting it to NYC-London. Building a plane for one route is never going to make any sense. Boom never had any real plans that I know of to fix the… boom
Boom hasn't solved the shockwave issue, have they? The Concorde didn't do overland routes over populated areas because of this. For example the NYC <-> Mexico City route overflew Florida for a time, and it would slow down to subsonic speeds over land. So even if Boom launches you likely wouldn't get cross-Europe routes.
One issue they face here is that for most flights, the time wasters aren't what happens once you are in the seat of the plane. It's everything that happens before that at the airport.
Usually, I breeze through with TSA Pre but neither myself nor my car service likes to bank on that. (Also slowdowns on my >1 hour drive to the airport.) To your point, even if it's not security, there's a certain amount of overhead and buffer for a lot of people going to the airport for a flight.
Yeah, that does seem like a massive drawback. Even hypothetically with SAF (Sustainable Aviation Fuel) from carbon capture that they’re spruiking, that’s still a huge amount of energy that could be used far more efficiently by not flying supersonic…
If it was more like 3x, that might make it work on a cost benefit in certain cases, but physics makes fools of us all it seems…
The part of Boom's argument that makes absolutely no sense to me -- their argument about how they will be "sustainable" because they will burn SAF -- is that the same argument could be applied to traditional commercial subsonic jet aircraft.
This company is the next Theranos, and I don't think it's even that bold of a statement to say.
They don't have an engine for a plane that they have yet to fly, for a concept that has limited commercial viability in the first place. We will look at companies like United and American Airlines that signed letters of intent to purchase these as foolish idiots.
In the day and age of remote meetings, there is nearly no alpha in being able to be in London three hours earlier from NYC. You would simply hop on a Zoom call if it were that urgent. Nobody is going to pay up for the cost if they are flying for leisure. There are limited viable routes in in the first place.
LOIs are nearly free. They're basically securing a spot at the front of the line just in case Boom manages to deliver.
Unlike Theranos, supersonic engines already exist and they are regularly used by the military. The issue is that none of the big boys are willing to pony up a lot of money to build, test and certify one for civilian use unless they can definitely get paid for their effort.
And yes, there are willing buyers who will pay ludicrous amounts for comfort or speed, as the increasingly elaborate arms race in first class (eg. multi-room suites a la Etihad's Residence) and the entire private jet market demonstrate. The Concorde was profitable towards the end of its life despite mind-bogglingly high fuel costs, so there's definitely a market if -- and it's a big if -- Boom can pull it off.
> This company is the next Theranos, and I don't think it's even that bold of a statement to say.
It’s a very bold statement to say when you have no evidence that Boom would or even could ship an airplane that would put people’s lives in danger.
Theranos was not simply a company that made large promises that required leaps in technology and then lied repeatedly about having succeeded in making those leaps. They risked patient safety by providing phony blood test results. It’s important not throw around that epithet unless it’s earned.
> They don't have an engine for a plane that they have yet to fly
To really be Theranos-tier, they'd have lied about having the engine already. They didn't go that far, they never claimed to have the engine already. Nor is the engine they desire one that's actually impossible, as Therano's vision was.
> Boom’s other partners include Safran Landing Systems, Collins Aerospace, fuel-system company Eaton and Northrop Grumman, which is helping with a military variant.
Does anybody know more about this "military variant"?
If it costs in the same ballpark per seat as a long range private jet, then for nearly all city pairs under roughly 5000km it's difficult to find an economic justification.
Especially if the plane needs long runways to takeoff.
Due to the travel times others have touched on to the major airports in nearly all big cities.
Lighter private jets have a huge advantage in travel time of being able to take off from the closest small airports.
If it's a really long route, like Sydney to London, then it would start making sense. But this could not support the thousands of engines needed to break even on R&D costs.
It's amazing how much of end-to-end travel time is NOT the plane flying. It would be much more cost-effective to optimize everything besides the actual flight time for almost all flights. Things like:
* Airport-to-city travel time
* Airport security time
* Optimize boarding (very straightforward solutions but require passenger education)
* Speeding up taxiing / takeoff sequencing (not sure how but there's gotta be a better way than what we do now)
Each of those are challenging but would be more impactful (and more solvable?) than supersonic flight time!
it also solves the 4th, since you typically are going to land your private jet at Teterboro instead of JFK or LGA (i.e. small fields without a lot of taxiing, or more importantly in NY, queuing for a runway (I've heard that we're 23rd in line for takeoff more times than I can count)).
I think the reality is that aerospace engineering is literal magic - the amount of resources, facilities, time and brainpower is absolutely it takes to develop anything approaching modern military hardware in performance makes it prohibitively expensive to fund the development on market terms.
Developing a jet engine that could allow Boom to meet its performance targets is a nation-state level endeavor.
Depends. If (and that's a mighty big "if") the fuel situation could be sorted out in terms of being able to produce it in a sustainable way, the footprint would be quite minimal compared most other modes of transportation.
You also wouldn't need to add any additional infrastructure as opposed to ideas like vac-trains or MAGLEV in general.
> You also wouldn't need to add any additional infrastructure as opposed to ideas like vac-trains or MAGLEV in general.
You still need one of the most expensive parts of that infrastructure which is the rights of way, stations/highway interchanges and a transport corridor from the city to an airport (which can't be as close as a conventional airport due to 5x the flight volume, louder engines and sonic booms).
The 900km of a rail corridor in the low population regions doesn't cost as much as that 30km of highway or metro tunnel directly under the CBD and 70km of arterials, onramps and interchanges.
Boom is basically a scaled down Concorde when you look at it from a distance. They've reduced the speed somewhat to keep the fuel burn within certain limits, but it has the same drawbacks that Concorde had: a supersonic boom and enormous fuel burn per passenger. In this day an age of Climate Hysteria this simply won't fly.
I foresee the failure of all supersonic airplane ventures until NASA comes up with a viable sonic-boom free design. Even then, the fuel burn could still make it unsalable.
I thought Boom had a smaller plane in the works. Trying to design a big 4 engine plane sounds daunting to me. A smaller craft with two engines sounds somewhat easier. Something able to transport 25 people maybe.
This article is a bit fallacious/misleading: I have no clue wether Boom design is vaporware or serious engineering but: 1) The initial premise, that there is a costly need to design a new engine is meta-unecessary AKA not necessarily necessary. The article raise 2 reasons for a new engine: fuel efficiency and noise reduction. I'd argue the concorde engine (the Rolls-Royce/Snecma Olympus 593) is excellent regarding efficiency -> The overall thermal efficiency of the engine in supersonic cruising flight (supercruise) was about 43%, which at the time was the highest figure recorded for any normal thermodynamic machine.[3]
I don't know for sure what is the SOTA efficiency nowadays but IIRC last generations engines are ~10% more fuel efficient than the ones from the 80s, which where at the time behing the Rolls-royce engine hence I even doubt modern engine have better thermal efficiency than aforementioned 43%. Regarding the topic of thermal efficiency, engines are not supposed to reach 43% without being supercritical, did Rolls-royce bypass physics laws? There must be something I ignore here. Anyway even if (?) we could design supercritical jet engines the best possible thermal efficiency would be 46-7% AKA a minor improvement.
Boom can increase fuel efficiency via the airplane architecture with e.g. composites. The near commercialisation new civil aircraft from china achieved a 10% reduction doing so. The same can be said for noise reduction. Hence what Boom should do is simply to order Rolls royce to produce the same engines again. However one should know that R&D for the successor of the concorde engine has already been spent and such engine has been designed. Unfortunately the U.S imperialist oppressive bans killed the concorde economics before the production of said engine, cf: https://en.wikipedia.org/wiki/Rolls-Royce/Snecma_Olympus_593....
Now about the noise levels let's adress the fact that it is a non-issue. 1) If you look at the empirical scientific comparisons, the mean noise of the concorde is significantly lower than many civil airplanes, especially the ones with 4 engines. 2) The boom while intense, is very transient. It is not heard from people inside the airplane. It is a non-problem for the obvious reason that your jet does not need to be supersonic for 100% of the trajectory, therefore a plane can and should go to very high altitude (already a supersonic requirement) and/or above low density population (rural, ocean) and only then bypass the speed of sound, making the noise boom a moot problem. While this solution is trivial, political bans and people hysteria isn't.
What is at stakes? A lot of things, supersonics isn't just cool, it is a life saving technology that can allow the transfer of key people in records time (expert surgeon in niche disease emergency for example) which can have very high utilitaristic value. It can also make it much more pratical for key people to meet physically (e.g. key academicians for a symposium about advancing the state of the art in a topic) which is high impact considering cognitive biases regarding human agency.
Note however there are other supersonic engine makers than rolls royce, for example any country that makes supersonic military jets can obtain such engines. It is easy to forget that the first commercial supersonic engine was not the concorde but a russian tupolev. While the tupolev has reliability issue, few know they had an alternative engine (likely more reliable). In addition to the tupolev engines, I would look into the state of the art https://en.wikipedia.org/wiki/Saturn_AL-31 Regarding SOTA civilian turbofan there is the https://en.wikipedia.org/wiki/Aviadvigatel_PD-14#PD-35 in development, although it can power an antonov (!) and seems very versatile I wonder if (not a turbojet) it can perform supersonicity without afterburners.
regarding those options however, russia bad, china bad.
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