scramjet

[mike wightman]

Good news , cheap space travel just came a step closer.
(Not to mention the military aplications- scramjet powered armour penetrators for example, high speed transports for special forces insertion etc.)

There is a bit more info here explaining a bit about how it works.

 

[vegascat]

My questions are;
What acceleration factor does it have?
How fast does it have to move to light its candle?
Is it going to be another 20 years before it is usable for anything other than a testbed?

 

[Richard Saunders]

Originally posted by vegascat:
[QB] My questions are;
What acceleration factor does it have?
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Depends on how much fuel you want to use.
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How fast does it have to move to light its candle?
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Slower than mach1 it was launched by a B52.
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Is it going to be another 20 years before it is usable for anything other than a testbed?
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Scram jets have been around for 30 years they are just not very efficient (you need to get them up to speed to fire the engine and if your speed drops below that speed the engine stops again, so you need two engine one to get you up to speed and the same one to land you).
If hypesonic flight is so good how come the Concord isn't around now, could it be the sonic boom, so how many towns are going to want the planes to fly over them doing mach8.
And if you think they will make great shuttles, how much air is there in orbit for the engine to breath, or are you going to bolt three engines on the shuttle.
Just my thoughts on the matter.
Bye.

 

[mike wightman]

Hi Lionel.

Originally posted by Lionel Deffries:
How fast does it have to move to light its candle?
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Slower than mach1 it was launched by a B52.
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It, and its modified Pegasus rocket booster, were launched from the B52 . Speeds of mach 6 are required before the scramjet can kick in.

Is it going to be another 20 years before it is usable for anything other than a testbed?
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Scram jets have been around for 30 years they are just not very efficient (you need to get them up to speed to fire the engine and if your speed drops below that speed the engine stops again, so you need two engine one to get you up to speed and the same one to land you).

The theory has been around a long time, but I don't think there have been many fully functional scramjets launched over the last 30 years

If hypesonic flight is so good how come the Concord isn't around now, could it be the sonic boom,

That, plus the reduced passenger numbers following 9/11. Most of the time Concorde was run at a loss as a prestige thing anyway (thanks to the Americans not buying any, but that's another story ). Notice how BA would rather scrap them than sell them on to Virgin Atlantic.

so how many towns are going to want the planes to fly over them doing mach8.

Do you notice when the shuttle goes overhead at mach12?

And if you think they will make great shuttles, how much air is there in orbit for the engine to breath, or are you going to bolt three engines on the shuttle.

I think the final concept involves either two engines or some sort of ramjet/scramjet combo with a final rocket booster. The idea is to make hypersonic troop transports, I believe .

 

[Aramond]

One of the first listed uses for Scram jets when they are feasableis for an Air Force next generation bomber, able to launch from CONUS(CONtinental US)to anywhere ontheglobe in 2hrs.

As far as use for space craft a scram jet can be designed to convert from Air breathing (H + air) to bi-propellant (H2 + O2) by closing the intakes and injecting the O2(granted there more technicals beyond this but this is the broad design concept). This technology holds the greatest potential for us to acually achieve a SSTO (Single Stage To Orbit) vehicle, with out the use of a nuclear powered propusion system.

 

[Straybow]

Some designers are looking at modified SSTO (a mid-air refuel) with one small jet and two large scramjet/rockets. The plane takes off on jet fuel, then takes on LO2 from a tanker. The jet fuel could be formulated to work in a rocket, or a separate fuel could be used (if LH2, it would be loaded from the tanker as well because of its bulk).

Eventually it would be 10% of the cost of vertical launch. Long before then we need heavy (vertical) lift capability.

 

[Drakon]

"Do you notice when the shuttle goes overhead at mach12?"

One time, I did.

I work nights at the local atom smasher. Our boss was listening to the radio, and called us all outside. Said the shuttle was coming overhead before touchdown in Florida, the other coast.

At about the right time, I saw this very disappointing, dimly lit object moving up over the horizon. Well that was not impressive, I thought.

And then the shuttle hove into view over the western mountains. It was the color of a bright red road flare, leaving a trail. After a few minutes, you could dimly hear the roar, but it was coming from far behind the shuttle.

It was the coolest site I have ever seen, the space shuttle returning to planet Earth at 3 o'clock in the morning (our time). By the time the wonder had faded enough for us to go back inside, the radio reported that she had touched down in Florida. Couldn't have been much more than 5 minutes since we lost site of it.

 

[cmdrx]

I notice it every time it lands here in Florida! Of course she's comming in a bit slower when we hear the sonic booms. You get used to it. I love it when the visitors or newcommers to central FL jump when the Shuttle is landing and dont know what the booms are.

After a year now, kinda miss seeing the Shuttle shots and the boom. It's like 1986-1988 all over again...

and yes I was there to see Challenger...