Scram Success

"Earl Colby Pottinger" wrote in message
...
(Henry Spencer) :

Me too. But as Rand notes, a successful *cheap* launcher is the
important
thing -- how many stages it has is a secondary issue, and there are some
differences of opinion :-) about the best number.

Major point, NASA wasted 1.3 Billion to am a SSTO, for that money you
probably could get three or more of the small and hungry rocket to make
working xSTO craft. and if any (ROTON anybody) did make a SSTO it would
probably be diffirent than NASA's.

Actually, if you're referring to X-33, NASA blew that money on a
demonstrator that would not have been anywhere close to an SSTO in terms of
velocity. This was more of a vehicle that was somewhere in-between DC-X and
a "real" SSTO. It was meant to demonstrate technology, but since it never
flew, it didn't demonstrate much.

Jeff
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"John Thingstad" wrote in newspshl2a2rnpqzri1
@mjolner.upc.no:

I would also want to allow for advances in both scram-jets
and rockets. Remember that another exciting NASA project
is testing out a revolutionary Russian rocket engine developed
for the scrapped Russian moon program. As far as I understood
(no I am not a rocket scientist) used a turbine to power the fuel
pumps and feed it into the thrust of the engine developing 20-30% more
thrust for the same amount of fuel.

Sounds like staged-combustion; that's old news. Do you
have any more specific information?

--Damon

On Wed, 17 Nov 2004 15:08:47 -0600, in a place far, far away, Damon
Hill made the phosphor on my monitor glow in
such a way as to indicate that:

I would also want to allow for advances in both scram-jets
and rockets. Remember that another exciting NASA project
is testing out a revolutionary Russian rocket engine developed
for the scrapped Russian moon program. As far as I understood
(no I am not a rocket scientist) used a turbine to power the fuel
pumps and feed it into the thrust of the engine developing 20-30% more
thrust for the same amount of fuel.

Sounds like staged-combustion; that's old news.

Yup, just like the SSME. The only thing different about the Russian
engine was that it used kerosene instead of hydrogen.

Not at all, I think. Lots simpler to use conventional rockets; scaling
a scramjet for heavy payloads is way off into the future, if it all.
There's a basic problem of just getting the vehicle up to a speed
where the engine will work at all, airframe heating/cooling, and
actually realizing the weight savings when the complex airframe eats
up the weight budget that came from the supposed oxidizer savings.

Isn't it a matter of geometry? If you for instance double the scale of a
scramjet, you quadruple its heat load as you quadruple its surface area, but
you also octuple the amount of hydrogen fuel and payload it can carry. It seems
that increasing the size of the scramjet increases the amount of paying payload
to a greater extend than it increases the heating problems. Whatever system is
used to handle frictional heating will only increase by the square of the
length of the scramjet. The more volume and it contains, the less the price per
unit mass it will be for sending things into space.

Tom

(Tkalbfus1) :

Not at all, I think. Lots simpler to use conventional rockets; scaling
a scramjet for heavy payloads is way off into the future, if it all.
There's a basic problem of just getting the vehicle up to a speed
where the engine will work at all, airframe heating/cooling, and
actually realizing the weight savings when the complex airframe eats
up the weight budget that came from the supposed oxidizer savings.

Isn't it a matter of geometry? If you for instance double the scale of a
scramjet, you quadruple its heat load as you quadruple its surface area, but
you also octuple the amount of hydrogen fuel and payload it can carry. It
seems that increasing the size of the scramjet increases the amount of
paying payload to a greater extend than it increases the heating problems.
Whatever system is used to handle frictional heating will only increase by
the square of the length of the scramjet. The more volume and it contains,
the less the price per unit mass it will be for sending things into space.

No, because no matter what the volume of the burn chamber the air-intake only
goes up by the square of the scale, and the amount of air/oxygen limits the
amount of power/thrust produced. So above the min size drag increases at the
same rate as thrust.

Earl Colby Pottinger

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sanman wrote:

So in light of these post-Nov16 statements from NASA, will there be a
future for scram?

Yes, but not for launchers.

Paul

Yes, but not for launchers.

Paul


You don't think a scramjet would be superior to the "White Knight" Scaled
Composites now uses? The "White Knight" is only a conventional Jet. Just think
of what can ride on it if it can actually reach space. A scramjet can do what
SpaceShipOne does now, but with only one stage. A second stage can reach orbit
from there.

For instance: a Scramjet can reach space at Mach 10, but it can't stay there.
From deep inside it's belly it can launch a rocket that can reach orbit. The
rocket would consist of fuel tanks, a rocket motor and a payload container. The
hydrogen tanks can be as big as they need be without consideration for
areodynamics since it will start above the atmosphere.

Tom

On 18 Nov 2004 03:08:03 GMT, in a place far, far away,
(Tkalbfus1) made the phosphor on my monitor glow in
such a way as to indicate that:

You don't think a scramjet would be superior to the "White Knight" Scaled
Composites now uses? The "White Knight" is only a conventional Jet. Just think
of what can ride on it if it can actually reach space. A scramjet can do what
SpaceShipOne does now, but with only one stage. A second stage can reach orbit
from there.

For instance: a Scramjet can reach space at Mach 10, but it can't stay there.
From deep inside it's belly it can launch a rocket that can reach orbit. The
rocket would consist of fuel tanks, a rocket motor and a payload container. The
hydrogen tanks can be as big as they need be without consideration for
areodynamics since it will start above the atmosphere.

Tom, you are utterly unknowledgable about physics, or launchers.
Please stop embarrassing yourself on Usenet.

Tkalbfus1 wrote:

You don't think a scramjet would be superior to the "White Knight" Scaled
Composites now uses?

For White Knight's mission? Of course not. For acting as a higher speed
first stage? It would be inferior to a rocket-based alternative.

Paul

On 18 Nov 2004 03:08:03 GMT, Tkalbfus1 wrote:

Yes, but not for launchers.

Paul


You don't think a scramjet would be superior to the "White Knight" Scaled
Composites now uses? The "White Knight" is only a conventional Jet. Just
think
of what can ride on it if it can actually reach space. A scramjet can do
what
SpaceShipOne does now, but with only one stage. A second stage can reach
orbit
from there.

For instance: a Scramjet can reach space at Mach 10, but it can't stay
there.
From deep inside it's belly it can launch a rocket that can reach orbit.
The
rocket would consist of fuel tanks, a rocket motor and a payload
container. The
hydrogen tanks can be as big as they need be without consideration for
areodynamics since it will start above the atmosphere.

Tom

I might add that X-54 uses a B-2 bomber to reach 20 000 meters altitude.
Then it uses a modified Pegasus booster rocket to reach Mach 10.
Then it engages the scram-jet.
We are far away from anything workable.
A rocket to launch a scram-jet to launch a rocket may
well be more trouble that it is worth.


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