Oxygen-Powered Jet Travels The World In 4 Hours | Hacker News Reader

Oxygen-Powered Jet Travels The World In 4 Hours

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6 pointsyottoy9 comments

The article title is misleading. An oxygen powered jet did not travel the world in 4 hours. An oxygen powered jet did not travel at all. An oxygen powered jet does not exist.

But someday, using this new engine technology, it might be possible.

"An oxygen powered jet did not travel the world in 4 hours" - TRUE, as I know of no aircraft that can carry a human at mach 9.

But without an oxidizer combustion is not possible. I don't know of any airplane (jet or propeller) that uses anything but oxygen as it's oxidizer.

Oxygen-Powered Jet Might Someday Travel The World In 4 Hours If Technology Proves Viable And Meets Actual Market Demand At Acceptable Cost

Near as I can tell, the article is mixing up two different things. SABRE is being tested as a rocket engine - it recently got some press on here because they had a successful heat exchanger test which, while pretty cool, does not an engine make. As I understand it since that test the ESA has given the nod to SABRE and believes there isn't any technical reason why the engine won't work.

The article mentions that the main advantage will be that "aircrafts can carry less load in terms of on-board liquid oxygen". This is presumably actually referring to rockets, not aircraft, since conventional jet aircraft already use regular old air. "massive throw-away first stages", again, hopefully refers to rockets, otherwise there might be some expensive property damage when your passenger jet drops its first stage on La Guardia.

There is an actual passenger jet piece, though. A separate initiative called the A2, a hypersonic passenger jet based on a derivative of SABRE. If built, it could apparently travel at Mach 5 and take you halfway around the world in something like 4.6 hours, which is pretty close to 4 if you squint.

All of this stuff is being planned by the same company, and Wikipedia says the plane's coming within 25 years "if there is market demand" - so although this all sounds good, and it's nice they've had a successful test, I think it's safe for now to treat this new oxygen-powered jet as vapourware.

(sorry)

The wikipedia article[1] is about 100 times as informative as this article. Apparently the technology was conceived of in the 50s, and it looks like basic hardware testing took place earlier this year.

I have no aerospace background but this reminds me of ramjets, which have been flying since the 40s but aren't used to transport people.

[1] http://en.wikipedia.org/wiki/SABRE_(rocket_engine)

This has a far better explanation of what the engine is about: http://www.bbc.co.uk/news/science-environment-20510112

There's also a documentary on the developers: http://www.youtube.com/watch?v=vZ_a21fPkYM

How is the SABRE engine any more oxygen powered than any other jet engine in air breathing mode?

From what I can grok from the article, the engine isn't interesting because it is an air-breathing jet engine, but rather because it is an air-breathing rocket engine. "Oxygen powered" seems to just be confused reporting.

Isn't "air-breathing rocket engine" a misnomer? A rocket is a jet engine that carries all of its propellant (fuel + oxidizer) on board, right?

From looking at the info posted, this thing appears to have two modes: jet (air-breathing) and rocket (non-air-breathing). It smells like they came up with the name first, then figured out an acronym to fit. :-)

If the load is lighter because the aircraft doesn't need to carry liquid oxygen, then does that mean it requires less fuel?

Or does oxygen-powered mean it requires no fuel?

I'm a bit confused by the brevity of the article...

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