Scramjet reaches Mach 7.6

The linked article describes the outcome of a test of a new scramjet a few months ago.

It includes a claim that a jet travlling at this speed would run from Sydney to London in under three hours.

My question is, what are the implications of this? Are we likely to see this used in commercial jets any time in the forseeable future?

[and if someone could tell me how to do those tricky links where you put your own heading over the hotlink rather than the whole URL, I’d be grateful]

Sure. Click on the Quote button in the bottom-right-hand corner of this post to see the coding.

Researchers label scramjet a success…Rest of world not convinced.

Er, I see a couple of problems with real-life applications, here–

–and here–

You have to be launched on the back of a rocket, and it burns up upon reentry? I don’t think the Business class of travelers in general will be too thrilled. It’s so difficult to talk on a cell phone while you’re hanging upside-down, strapped into a harness… :smiley:

How to disguise a url
Type it in like this:
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Except that you should use square brackets instead of the curly brackets { } used here. The hamsters won’t let me post examples of square bracket code without turning it into an actual link.

Also, check out the vB Code help link on the page.

As for the actual OP topic, I suspect we won’t see this type of hypersonic or suborbital vehicles used for commercial flights for some time. They’ll be military first.

NASA also has their own experiment program, the Hyper-X (aka X-43). Not much luck there though - the X-43 vehicle is designed to fly on a Pegasus rocket, but the rocket failed on the first flight.

That’s where current scramjet technology is at - accelerating prototype engines using rockets and observing how it behaves in flight. I want to say it will be practical in 10 years, but people have been saying that for the past 10 years so I wouldn’t hold my breath. It’s still an important basic research though.

At the very least, I can picture the U.S. Air Force and CIA creating disposable scramjets that fly over enemy areas, take a billion pictures for transmission back to Washington, and then splash in the ocean. Sort of a one-shot SR-71 Blackbird.

It would be ridiculously expensive, but when did that ever stop them?


The only commercially operated supersonic aircraft is the Concorde, which continues to operate out of British and French national pride since it has never turned a profit.

Apparently, people just don’t need to move that fast. Or else they can’t afford it. Or both. A scramjet would undoubtably be even more expensive to run.

This sort of thing is done as research, pure and simple, with perhaps some military application down the line. At least for the foreseeable future.

Broomstick & Sunspace’s points about the military use is well taken. The Russians are already attempting/testing Scramjet technology as an end stage ICBM, as a way to potentially defeat a missile defense system.

BTW, not that anyone said anything different, but to be clear it seems likely that the X-43A failed not because of the scramjet itself, but because of a failure in the booster rocket control area. Or at least that is the current thinking.

Scramjet technology is aimed at launching “light” satellites and payloads into orbit. Or at least thats what the company wants to do in Australia, its not aimed at commercial passenger jets.

The OP asks about commercial applications. This technology is quite old as aircraft technology goes - Ramjets were first used by the Germans in WW2, and I suspect the technology is older.

The technique is good for travelling at high speed, but not much good for getting up to it, or slowing down, so that is an extra complication.

The first commercial proposal I know of for ScramJet use was in conjunction with WaveRider technology, which was invented in Britain in the early 50’s. Then the aim was for rapid travel between places in the Empire, so you can see how old the ideas are. The Concorde is one end result of that research thrust. Here is a link to some of the history:
Though ScramJets are quite simple, and do not seem to be difficult to make work, the real technological problem is the fluid mechanics of flying at these speeds. Air friction at low altitudes limits aircraft to below about 2k - beyond this you gain more heat than you loose, and you cook. So travelling at hypersonic speeds needs to be done at the edge of the atmosphere, which might make the shock-waves easier to minimise. These are the reason the Concorde is so limited in where it can fly.