Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

British aerospace company claims biggest engine advance since the jet

uk.reuters.com

Post reply on HN
Print view View original

41–50 of 109 posts

Re: British aerospace company claims biggest engine advance since the jet

#41

Post by robomartin »

The MAGLEV Launcher.

http://en.wikipedia.org/wiki/Rocket_sled_launch

http://www.reallyrocketscience.com/node/2393

Using MAGLEV as a launch assist technology to offset the amount of energy derived from burning tons and tons of fuel. Some of the articles estimate a potential to increase payload by 80% compared to a conventionally launched rocket.

If you want to get a little deeper into it, this is a good read:

http://upload.wikimedia.org/wikipedia/commons/5/58/Maglifter...

Some fun data points:

    Power for large scale system: 10GW for 20 seconds. 
    Thermal Management system capable of dissipating 40GJ.
What's the probability of this ever being built? In the US, my guess is zero. I could see the Chinese throwing money behind such a crazy project if the numbers make any sense at all. If a system like this can significantly reduce cost to orbit it could represent a huge competitive advantage.

Re: British aerospace company claims biggest engine advance since the jet

#42

Post by schiffern »

tzs wrote: post #34

> This core piece of technology solves one of the constraints that limit jet engines to a top speed of about 2.5 times the speed of sound, which Reaction Engines believes it could double Is that 2.5 times the speed of sound limit just for jets at low altitude? At high altitude it is certainly not true. Both the SR-71 and MiG 25 did well over Mach 3.

They mean turbojets ("conventional" jet engines). The SR-71 doesn't use a conventional jet engine.

http://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Engine...

>A unique hybrid, the engine can be thought of as a turbojet inside a ramjet. At lower speeds, the turbojet provided most of the compression and most of the energy from fuel combustion. At higher speeds, the turbojet largely ceased to provide thrust; instead, air was compressed by the shock cones and fuel burned in the afterburner.

Re: British aerospace company claims biggest engine advance since the jet

#43

Post by schiffern »

robomartin wrote: post #41

The MAGLEV Launcher. http://en.wikipedia.org/wiki/Rocket_sled_launch http://www.reallyrocketscience.com/node/2393 Using MAGLEV as a launch assist technology to offset the amount of energy derived from burning tons and tons of fuel. Some of the articles estimate a potential to increase payload by 80% compared to a conventionally launched rocket. If you want to get a little deeper into it, this is a good read: http://u…

The payoff would be immense though. At datacenter electricity prices, the fundamental energy cost to LEO is about 50¢/kg.

Re: British aerospace company claims biggest engine advance since the jet

#44

Post by schiffern »

Osmium wrote: post #24
mtgx wrote: post #5

Elon Musk was specifically asked about this technology when he was at Martin School last week. He didn't hear about it, but he seemed skeptical that it would work better than rockets. His response here: http://youtu.be/c1HZIQliuoA?t=48m55s SpaceX might still be the first one with a re-usable rocket if they finish the Raptor engine in 3 years. Plus, his could actually be used to land on Mars, while this can only be us…

SpaceX are absolutely right to be using tried-and-tested technology in their rockets, and so Elon Musk's scepticism is sensible in context of what they're trying to achieve. The technology mentioned in this article is more applicable 10, 20 years down the line; the R&D costs would be prohibitive to make it cost-effective to be used by SpaceX now, even if they could get it to work reliably and secure the IP rights.

>tried-and-tested technology

His objection isn't based on technology though. It's based on physically enveloping the problem and comparing the two cases.

His assumptions seem to be: LOX will remain cheap. The atmosphere will still have 21% oxygen. Your technology can't separate the N2 from the O2 before ingestion.

Elon says that the braking effect of ingesting that nitrogen vastly overwhelms the small benefit of having a smaller O2 tank. That's it.

This argument doesn't rely on the air-breathing stuff being more complicated or expensive or heavy (though it will be). Technology might fix those problems, but that simple kinematic fact is enough.

Re: British aerospace company claims biggest engine advance since the jet

#46

Post by geori »

robomartin wrote: post #41

The MAGLEV Launcher. http://en.wikipedia.org/wiki/Rocket_sled_launch http://www.reallyrocketscience.com/node/2393 Using MAGLEV as a launch assist technology to offset the amount of energy derived from burning tons and tons of fuel. Some of the articles estimate a potential to increase payload by 80% compared to a conventionally launched rocket. If you want to get a little deeper into it, this is a good read: http://u…

Elon might build it for the Hyperloop, if you believe the speculation on the hyperloop blog posts last week.

Re: British aerospace company claims biggest engine advance since the jet

#47

Post by east2west »

I wonder how this will impact air travel. It is a real shame that after Concord retired there is no supersonic jetliner in service, which at least kept the dream alive even if Concord is expensive and short legged. I believe no viable program exists right now for supersonic jetliners. The problem, if I recall correctly from my aerospace professor, is not the jet engine's thrust but heat generated from friction with air. If this Sabre engine can get the airplane mostly out of atmosphere cheaply, heat problem can be alleviated. I don't know how practical my guess is, but if it works, the market potential is immense.

Re: British aerospace company claims biggest engine advance since the jet

#48

Post by stcredzero »

schiffern wrote: post #43
robomartin wrote: post #41

The MAGLEV Launcher. http://en.wikipedia.org/wiki/Rocket_sled_launch http://www.reallyrocketscience.com/node/2393 Using MAGLEV as a launch assist technology to offset the amount of energy derived from burning tons and tons of fuel. Some of the articles estimate a potential to increase payload by 80% compared to a conventionally launched rocket. If you want to get a little deeper into it, this is a good read: http://u…

The payoff would be immense though. At datacenter electricity prices, the fundamental energy cost to LEO is about 50¢/kg.

Fuel (energy) cost is less than 1% of the cost to launch. The big costs are manpower, maintenance, and refurbishment.

Re: British aerospace company claims biggest engine advance since the jet

#49

Post by robotresearcher »

user24 wrote: post #32
javert wrote: post #13

Earlier quoted context omitted.

As an American, I parsed the title as "a British aerospace company..." not "the British Aerospace company..."

As an Englishman, I parsed the title the same way as you did, though I did wonder if it meant BA.

BA is British Airways. BAE Systems is the new name for what used to be British Aerospace, which used BAe as its abbreviation, to avoid confusion with BA.

I don't know why it bothers me, but I really dislike the used-to-be-an-acronym-but-not-any-more names. For example SRI (not affiliated with Stanford so the S doesn't mean that any more), and my least favourite "HRL Laboratories" which we have to pretend does not expand to "Hughes Research Laboratories Laboratories". Yuk.

Re: British aerospace company claims biggest engine advance since the jet

#50

Post by ChuckMcM »

stcredzero wrote: post #48
schiffern wrote: post #43

Earlier quoted context omitted.

The payoff would be immense though. At datacenter electricity prices, the fundamental energy cost to LEO is about 50¢/kg.

Fuel (energy) cost is less than 1% of the cost to launch. The big costs are manpower, maintenance, and refurbishment.

That was the interesting takeaway from the Elon Musk talk about how cheap the fuel was compared to everything else. Having the Skylon be reusable then shifts some of the operational costs back to fuel.

Of course a plane that can fly a Mach 5 and 100,000' has other uses, the most obvious one being the SR-71 replacement. Nothing like a bit of high speed aerial surveillance "right now" to help folks on the ground make better decisions. I'm sure someone would pony up the $400M they need.

Post reply on HN