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
#2People 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 aerobraking while it glides to its destination, before reengaging propulsion prior to landing on an airstrip (because passenger planes need to be able to abort landings and do multiple attempts). Not sure how reverse thrust would work there - variable geometry rocket bells?
Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft
#3What would a ticket cost like? 50k? Aren't those people in their own fancy private jet with whiskey, massages and party?
Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft
#4The actual time to skim off IMO is all the airport procedures.
Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft
#5>At that elevation at Mach‑5, air around the nose and leading edges can reach temperatures exceeding 1,000 degrees Celsius (1,832°F), a challenge...
It is not the conical nose or leading edges that are the show stopper problem(s). There the shockwave generally does not touch the craft. The internal shockwaves that touch the walls of the engine ducting are. The heat loading and heat soak ability on those shockwave impingement sites will limit the duration of hypersonic travel.
Hypersonic travel through the atmosphere is easy, a problem solved in the 1950s. Be conical and carry your oxygen internally. Hypersonic travel that is air-breathing is an entirely different class of problem and I don't think it is anywhere near to being solved.
The only silver lining is that at hypersonic speeds you don't need to be propulsive for very long to get anywhere.
Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft
#6Cool 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.
Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft
#7What would a ticket cost like? 50k? Aren't those people in their own fancy private jet with whiskey, massages and party?
Or have their own room in first class... Maybe time trade off isn't worth it for most of the people who can afford it at that point.
Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft
#8People 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…
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Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft
#9Cool 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.
Whenever you look at supersonic or hypersonic commercial aircraft plans you should assume one of two things.
A. It's a bait and switch by a founder who wants to pivot to weapons/military aircraft but wants to be able to hire high grade talent without paying the "we're gonna kill people" premium, can pivot once a good chunk of the workforce is complacent with a paycheck. You laugh but this happens SO FUCKING MUCH.
B. It's for business jet scale operations for billionaires. There are >3000 billionaires and however many corporate aviation departments and if you can build a super/hypersonic private jet that's not horribly expensive to operate the "time savings"* for that class of person will demand they buy one.
* when I say time savings I mean dick measuring contest
Re: A successful Japanese trial of a ramjet engine designed for Mach‑5 aircraft
#10What would a ticket cost like? 50k? Aren't those people in their own fancy private jet with whiskey, massages and party?
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