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A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

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Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#41

Post by Nesco »

deadbabe wrote: post #37
rdl wrote: post #28

Earlier quoted context omitted.

Vastly more favorable today than it was when Concorde flew. 1) Rich people are WAY richer, and time is even more valuable 2) Businesses have some very important employees and "2 day trip" vs "3-4 day trip" is worth $50-100k 3) Larger population of people able to pay $20-30k for a flight than ever before. The biggest practical impact is there's probably going to be a private jet version instead of just a commercial on…

What are some examples of employees so important you would pay $100k to get them somewhere immediately?

American execs negotiating memory two months ago in Korea?

Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#42

Post by nine_k »

kelseyfrog wrote: post #31
rbanffy wrote: post #2

People say this like it's a simple engineering problem. No. By itself, a new hypersonic engine can't make 2-hour flights between Japan and the US a reality. We are not even close to being able to build an aircraft that can do that - we don't even have the materials for that. What seems "easier" (as in "less impossible") is a hypersonic glider design that enters a suborbital trajectory and does shuttle-like aerobrakin…

How long of a weightlessness period does this entail?

Maybe not complete weightlessness, because at 80-90 km the atmospheric drag is still noticeable. But it should be enough of a unique experience.

Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#43

Post by infecto »

deadbabe wrote: post #37
rdl wrote: post #28

Earlier quoted context omitted.

Vastly more favorable today than it was when Concorde flew. 1) Rich people are WAY richer, and time is even more valuable 2) Businesses have some very important employees and "2 day trip" vs "3-4 day trip" is worth $50-100k 3) Larger population of people able to pay $20-30k for a flight than ever before. The biggest practical impact is there's probably going to be a private jet version instead of just a commercial on…

What are some examples of employees so important you would pay $100k to get them somewhere immediately?

You are not thinking high enough the food chain. I mean heck you have tenured SV engineers cracking $1mm with RSUs. It’s not rare in finance for folks to be hitting $3-5mm with bonus. So that’s what $19k comp a day. If that individual is making $5mm they are more than likely making a multiple of that for the organization.

Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#44

Post by pdonis »

BurningFrog wrote: post #40
Padriac wrote: post #30

I imagine passengers will be exposed to very high noise levels during flight.

I don't have a good intuitive feel for that. At 25km altitude, with 1% of normal atmosphere, maybe you're close enough to vacuum that it can get really quiet?

The engine noise can still be conducted through the body of the plane. With the kind of ramjet being talked about, I think that's still likely to be significant even at very high altitude.

Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#45

Post by bobthepanda »

infecto wrote: post #43
deadbabe wrote: post #37

Earlier quoted context omitted.

What are some examples of employees so important you would pay $100k to get them somewhere immediately?

You are not thinking high enough the food chain. I mean heck you have tenured SV engineers cracking $1mm with RSUs. It’s not rare in finance for folks to be hitting $3-5mm with bonus. So that’s what $19k comp a day. If that individual is making $5mm they are more than likely making a multiple of that for the organization.

Even these days, a lot of retailers operate fleets of private jets even for district or regional managers, because it saves somebody like Walmart a lot of paid hours to fly someone from rural town A to rural town B rather than potentially deal with the hassle of an overnight booking at an airport hub.

Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#46

Post by bigfatkitten »

nine_k wrote: post #32
HNisCIS wrote: post #20

Earlier quoted context omitted.

For pure generic full-stack-whatever devs yes. For EEs, embedded, FPGA, RF, etc you can pull waaaaay more in the defense world, especially if you're willing to do cleared work.

But if you need clearance to do your work, how can it be bait-and-switch? You need to hire people who are able and willing to obtain a clearance.

And have work that allows employees to keep their existing clearances active.

Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#47

Post by bigfatkitten »

nine_k wrote: post #34
Seattle3503 wrote: post #13

Earlier quoted context omitted.

What companies are examples of that bait and switch strategy?

Google tried to become a national security contractor, and the backlash among the engineers was very intense.

Google already does national security work.

https://cloud.google.com/distributed-cloud-air-gapped

https://www.defence.gov.au/news-events/releases/2025-12-19/d...

Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#48

Post by stouset »

wat10000 wrote: post #36
hdndjsbbs wrote: post #21

Earlier quoted context omitted.

I think a lot of the Concorde failure is tied to its status as a British-French project. Trans-Pacific flights are much longer and there's a lot of money in PEK -> LAX than in JFK -> LHR. Qantas wanted to offer London to Sydney, but they couldn't fly supersonic over land. Mainland China or Japan to Australia is a feasible route for high-margin, low-capacity supersonic flights. If you could make the flight from Beijin…

Everyone thought SSTs were going to be the next big thing. Both the US and USSR had projects. The 747 got a hump so it could easily be converted to a freighter once it was made obsolete by supersonic passenger planes. Despite two superpowers making the attempt, and plenty of time for more tries since then, Concorde is the only one that came even remotely close to something commercially viable. I’m sure there’s a mark…

You’re hinting at another huge part of the issue.

There are no economies of scale to be had here. If there are only a handful of plausible economically-profitable routes, all of the expenditures on R&D, testing, certification, and production facilities can only be amortized across a handful of aircraft.

Once you’ve built a dozen or two of them and a handful of extra engines and spare parts… what then? There’s no point in keeping the production lines open.

From an airline’s perspective, they have to now have an entire separate chain of employees (pilots, mechanics) dedicated to another airframe that barely makes up a fraction of their fleet. That’s a lot of overhead for two or three routes.

Those are some pretty big structural disadvantages that need to be overcome in order to make a boutique supersonic route appealing.

Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#49

Post by amanaplanacanal »

darkteflon wrote: post #6

Cool science. But the article fails to take even a cursory stab at contextualising the plan against the economic, environmental and political backdrop - doesn’t even mention that there’s already been one failed supersonic commercial flight programme. This is as pie-in-the-sky as it gets.

I think the SpaceX plan for point to point travel might be even more pie in the sky. Or maybe a tie.

Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft

#50

Post by mckn1ght »

bobthepanda wrote: post #33
decimalenough wrote: post #25

Earlier quoted context omitted.

There is a lot of money in NYC-LHR, that's why Concorde continued to fly that route and profitably too, once they realized how high they could yank the prices and still fill the plane. Also, Concorde's maximum range was 4,488 mi, which was calibrated to allow trans-Atlantic but not much more. Trans-Pac was not an option and even Australia to North Asia would be a stretch.

I think they are agreeing with you re: the range. There is money in NYC-LHR (it brings BA alone $1B in revenue annually) but the market for supersonic basically vanished. In the 70s when Concorde started flying, it was certainly a step up. However, the market niche basically disappeared when the lie flat seat was developed; for a lot cheaper, you could have a sleep for six hours in a really cushy lie flat, or you cou…

You can also essentially work remotely in an airplane now. I haven’t tried videoconferencing, but I easily do all my other software work on trips. So a couple extra hours might even be a benefit: more time with no distractions to wrap up that slide deck, maybe a 1:1 or two, get your free drinks from premium/business class, doze off to a movie, wake up for an early start at your destination.
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