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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

#151

Post by octaane »

fancyfredbot wrote: post #126

For many many reasons this engine only has one economic application - delivery of a nuclear payload in a way which is very hard for missile defences to stop. ICBMs can go faster than this already but as I understand it they go higher allowing for earlier detection and they follow a more predictable trajectory which makes interception more realistic. I find super fast missiles far scarier than advanced AI. I suppose t…

My take is also a missile, but as an interceptor, not offensive purposes. North Korea has shown that they can deliver a payload to Japan if they want. If the NKs do decide to launch something at Japan, it's not going to be tipped with conventional explosives. It'll be a nuke. Hypersonic interceptor seems the more likely application is this tech to me.

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

#152

Post by eagleal »

phire wrote: post #110

Is a Mach-5 passenger aircraft actually the goal of this project? Seems more likely that Japan is designing this engine for a hypersonic cruise missile program, and the passenger aircraft concept is somewhat of a cover. IMO, there is no point in a Mach-5 Aircraft (other than cruise missiles). There is potentially some point in Mach 2-3 aircraft, (not that we have ever made them commercially viable) but at the boundar…

Japan, Italy and UK have a program for a competing F35 design, GCAP. And Japan is focusing mainly on the engines.

Given there will at some point be the need to deliver competing cruise missiles for this platform, and after the crisis of the US not being able to keep demand with Israel's and Ukraine's orders they greenlighted SK and Japan to enter the European defense market, to answer your question yes, this is of course a defense related project.

There's been an industry request to develop native defense components on these matters within the EU following pressures and contrasts with the US (on a report to the EC for the ReArm campaign, EU's biggest playes of aerespace industry made a joint report estimating 60-80% of their components and tech are sourced from the US).

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

#153

Post by throwaway2037 »

emptyfile wrote: post #130
fancyfredbot wrote: post #126

For many many reasons this engine only has one economic application - delivery of a nuclear payload in a way which is very hard for missile defences to stop. ICBMs can go faster than this already but as I understand it they go higher allowing for earlier detection and they follow a more predictable trajectory which makes interception more realistic. I find super fast missiles far scarier than advanced AI. I suppose t…

Well here's an economic application without nuclear tipped warheads. https://en.wikipedia.org/wiki/Meteor_(missile)

The Wiki pages says top speed is about Mach 4. There are already multiple rockets from US, Russia, and China that can achieve the same (or more) but with a solid-fuel rocket motor. What is the advantage of a ramjet here? It just seems way more complex and much less well tested (in labs and in combat). Also, has this missile (Meteor) been used in any combat scenarios? To be clear, the max speed for any fighter jet is about 2.5 Mach. Once one (or two) of these missiles has locked on, you are done. I read some funny commentary once about how to shoot down a modern fighter jet: Two missiles. They can dodge the first one, but sacrifice so much speed, that the second one can easily find its target.

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

#154

Post by RicardoLuis0 »

b65e8bee43c2ed0 wrote: post #145
fancyfredbot wrote: post #126

For many many reasons this engine only has one economic application - delivery of a nuclear payload in a way which is very hard for missile defences to stop. ICBMs can go faster than this already but as I understand it they go higher allowing for earlier detection and they follow a more predictable trajectory which makes interception more realistic. I find super fast missiles far scarier than advanced AI. I suppose t…

judging by what we saw so far in Russia, Ukraine, and Israel, defensive missiles don't require particularly sophisticated offensive missiles to overwhelm.

yeah, but those are using conventional explosives, only countries like the US and Russia have enough nukes to do the same with nuclear explosives, a country like japan would need a sophisticated missile instead

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

#155

Post by api »

I kind of think today's air travel is in an uncanny valley.

I'd prefer either: just as uncomfortable or even more so but very fast, like multiple mach numbers fast. I live in the Midwest and go to the West Coast often, and it usually takes 5 hours -- I'd cram into a less comfortable seat for 2 hours instead to get there at mach 2.5.

OR... airships. Big cushy seats. A lounge with fast wifi and desks. A coffee shop. You can walk around. The trip takes all day, or overnight with a sleeping cabin. Trains could fill this niche too, but airships could go overseas.

Go faster or go roomier.

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

#156

Post by throwaway2037 »

abbadadda wrote: post #129

I actually learned about what a ramjet is after looking up the definition of “scramjet” when watching the _Top Gun: Maverick_ movie with my son. This is at the beginning of the movie when he is flying the Dark Star plane designed in conjunction with Skunk Works from Lockheed Martin. Well, we are obviously a ways away from Mach 10 reached in the film by the SR-71 Blackbird descendant, the new technology pushing Mach 5…

As I understand, the problem with anything over Mach 4 (or 5), the metal begins to disintegrate. It is fine for a one way missile, but not a reusuable aircraft. Without some alien tech (see 1990s game "X-Com 2"), I cannot believe that we can build a reusuable aircraft that can reliably and safely fly for long periods over Mach 5.

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

#157

Post by airstrike »

loloquwowndueo wrote: post #141
newsclues wrote: post #139

Earlier quoted context omitted.

I find fast missiles with AI to be pretty scary. Heck a slow drone with AI targeting chasing me is bad enough...

You only need to draw a fake moustache on yourself to fool it, or something.

like a backpack from which a cardboard version of a soldier springs out, with the operator being shielded with an aluminum foil pane

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

#158

Post by throwaway2037 »

fragmede wrote: post #68
XorNot wrote: post #58

Earlier quoted context omitted.

12 hours on a plane is 12 hours on a plane. And there's currently no amount of ticket money that can make that shorter.

Shorter, no, but having a private cabin with a shower, and a lounge with a bartender on the plane, not to mention Starlink, would make those 12 hours a lot more bearable vs 12 in an economy seat.

    > having a private cabin with a shower
AFAIK: Showers are only available to first class customers flying via the major Gulf carriers. I checked Google flights for business class and first class tickets between Tokyo and London. Business is about 5,000 USD and first class is about 10,000 USD. Assuming that we are talking about first class here (to satisfy your shower requirement), what kind of developer is hacking code at 10,000 meters in first class... except... hmm... Mitchell Hashimoto?

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

#159

Post by ranger207 »

throwaway2037 wrote: post #153
emptyfile wrote: post #130

Earlier quoted context omitted.

Well here's an economic application without nuclear tipped warheads. https://en.wikipedia.org/wiki/Meteor_(missile)

The Wiki pages says top speed is about Mach 4. There are already multiple rockets from US, Russia, and China that can achieve the same (or more) but with a solid-fuel rocket motor. What is the advantage of a ramjet here? It just seems way more complex and much less well tested (in labs and in combat). Also, has this missile (Meteor) been used in any combat scenarios? To be clear, the max speed for any fighter jet is…

Missiles versus aircraft is a fight between very high kinetic energy in the missile, and relatively low kinetic energy in the plane, but with the ability to generate more kinetic energy. Missiles don't have a lot of fuel, so they need to generate a lot of kinetic energy to still be effective by the time they reach the target. Typically a missile will accelerate to its top speed in the first few seconds of flight and coast the rest of the way. At very long ranges, all the energy generated when launched has bled off, so there's two common solutions for long-range missiles to generate more energy: a "dual pulse" motor is basically a second rocket motor that fires later in the course; or a ramjet, which can be throttled up and down and is more fuel efficient than a rocket engine.

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

#160

Post by ses1984 »

RicardoLuis0 wrote: post #154
b65e8bee43c2ed0 wrote: post #145

Earlier quoted context omitted.

judging by what we saw so far in Russia, Ukraine, and Israel, defensive missiles don't require particularly sophisticated offensive missiles to overwhelm.

yeah, but those are using conventional explosives, only countries like the US and Russia have enough nukes to do the same with nuclear explosives, a country like japan would need a sophisticated missile instead

You can fire a lot of decoys and one nuke.
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