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

rbanffy

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 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?

holoduke

What would a ticket cost like? 50k? Aren't those people in their own fancy private jet with whiskey, massages and party?

atoav

The actual time to skim off IMO is all the airport procedures.

superkuh

>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.

darkteflon

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.

domoregood

Ahh, but can it run DOOM...?

Padriac

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

nubinetwork

I've always wanted someone to bring back the Avro Arrow to use the Iroquois engine for freight, but I don't think anyone has the knowledge to even pull it off anymore.

laughing_man

Boy, that's an evergreen headline.

brandelune

Two news items in one : Japan is getting ready for hypersonic missiles, and Japan’s elite does not give a damn about global warming.

MarxOk

As a Canadian who travels to Europe about once per month I am very excited for this :D

belviewreview

Interesting, but assuming they can get the engine to work as intended, the question still remains how the passenger jet would get up to Mach 5 so the engine can start working. A solid-fuel rocket booster that would then drop off?

Ngraph

First time I heard the word "ramjet" was as a kid watching the Goliath episode of Knight Rider. Definitely not a documentary, but the word stuck. Then the Blackbird showed up in some plane book, and that was that. Ramjets back in the news. Kid me is having a great morning.

rusk

We had Concorde - it was too expensive to operate safely.