Scram Success

Jeff Findley wrote:

"sanman" wrote in message
om...
So you've all probably read that the latest Mach10 flight was
successful. The statements from NASA's O'Keefe seem to indicate that
this technology will be used to advance commercial flight, as well as
cheaper access to space.

Both of these are bogus arguments. The Concorde demonstrated that there is
little demand for supersonic flight. In today's post-9/11 world, we'll

Wrong. Concorde demonstrated that getting the politics right is a
presupposition to making money in some cases.


Jeff

--
Sander

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"sanman" wrote in message
om...
So you've all probably read that the latest Mach10 flight was
successful. The statements from NASA's O'Keefe seem to indicate that
this technology will be used to advance commercial flight, as well as
cheaper access to space.

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

Some of you have said it's easier to get into space with a rocket, but
some of the news coverage I was reading said scram could at least be
used for a lower-stage booster.

Could scram be suitable for heavy payloads in particular?

Scramjet can't be used for commercial space flight as using rockets is much
easier. Rockets can operate from a stand still in atmospheric conditions to
orbital velocity in vacuum. Why use scramjets? I believe the technolgy will
stay hidden anyway since it can easily be adapted for military purposes.

Scramjet airplanes? Use too much fuel per mile per kg. I mean, Concorde has
just been scrapped due to economics. No, supersonic flight won't become a
reality until we have an abundance of cheap, clean energy.

"sanman" wrote in message
....
So you've all probably read that the latest Mach10 flight was
successful. The statements from NASA's O'Keefe seem to indicate that
this technology will be used to advance commercial flight, as well as
cheaper access to space.

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

NASA has nothing in the '05 budget for any further hypersonic research. :-(

I have no idea what O'Keefe is talking about, esp. about applications to
commercial flight.

The military does have a few programs in hypersonics

John Thingstad wrote:

I looked over the web site at Venture Star, but I never figured out
why the program was scrapped.
Were there fundemental problems or just that they lagged behind scedule?

Because the fuel tank -- the main structural element of the X-33 around
which everything else was attached -- blew up the first time it was
fueled.

Mike

-----
Michael Kent Apple II Forever!!
St. Peters, MO

"Michael Kent" wrote in message
...
John Thingstad wrote:

I looked over the web site at Venture Star, but I never figured out
why the program was scrapped.
Were there fundemental problems or just that they lagged behind scedule?

Because the fuel tank -- the main structural element of the X-33 around
which everything else was attached -- blew up the first time it was
fueled.

Not quite.



Mike

-----
Michael Kent Apple II Forever!!
St. Peters, MO

On Sun, 21 Nov 2004 02:11:48 GMT, Michael Kent
wrote:

John Thingstad wrote:

I looked over the web site at Venture Star, but I never figured out
why the program was scrapped.
Were there fundemental problems or just that they lagged behind scedule?

Because the fuel tank -- the main structural element of the X-33 around
which everything else was attached -- blew up the first time it was
fueled.

Mike

-----
Michael Kent Apple II
Forever!!
St. Peters, MO


Thank you. I specuated about that.
I could see problems of cryogenic temeratures static loads and vibration
wreacing havoc with composites. I am not an expert but it seemed
'riscy'

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"John Thingstad" :

Thank you. I specuated about that.
I could see problems of cryogenic temeratures static loads and vibration
wreacing havoc with composites. I am not an expert but it seemed
'riscy'

But you should also note that Scaled Composites did build cryogenic tanks
that worked for both the DC-X and ROTON, however that is not who NASA looked
to build thier tanks. And the X-33 tanks did not so much as explode as the
cells in the tank walls developed high pressures because of internal leaks
that separated the diffirent layers.

Earl Colby Pottinger


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It also would've cost far more than Scaled Composites could ever have
dreamed of spending, and hypersonic seperation and staging is not a
trivial thing at all.

You don't separate in the atmosphere, you separate above it. The second stage
is carried inside the scramjet carrier so there is no airstream to consider
when the second stage is separating from the scram.

Dropping things off your plane (including another plane) at subsonic
speeds is old, comfortable technology. Doing so at the highest altitude,
not necesairily the highest speed, to reduce drag on SS1 and for its
nozzle to be most efficent (its expansion needed to be only a compromise
between launch altitude and vacuum, not sea-level and vacuum) was the
key...

Well what's the highest altitude that a scramjet can receive lift from the
atmosphere? If it can go Mach 10 at that altitude, what then happens if it
pulls into a climb and soars into space? Or perhaps the separation ought to
occur at the highest cruising altitude. The atmosphere is bound to be very thin
at this altitude.

Tom

Scramjet engines would necessairily be cheaper?


its fairly simple, it merely injects hydrogen into the airstream and the
shockwave ignites it.

And, by definition, must stay *in* the atmosphere as it does so,
facing increasing heat and drag. And high temprateure materials to do
this may or may not be rather expensive...

You mean that if a scramjet is breathing oxygen as it cruises at MACH 10 in the
upper atmosphere and it suddenly pulls up, then the scramjet will come to a
sudden and instantaneous stop once it reaches an altitude where it can no
longer pull in enough oxygen to ignite all of its fuel? Would that be like
crashing into the ground at MACH 10, by any chance?

There is a little thing called momentum, a lack of oxygen or vacuum is not
going to bring the scramjet to a sudden halt. Gravity will slow it down, but
only its upward component at a rate of 9.8 meters per second squared.

(Tkalbfus1) :

Scramjet engines would necessairily be cheaper?


its fairly simple, it merely injects hydrogen into the airstream and the
shockwave ignites it.

No, it is very complex shape that needs lots of research money to design.
Expensive and hard to work materials that costs still more. And very limited
in it's thrust so it takes a long time to accellerate to the max speed.

And, by definition, must stay *in* the atmosphere as it does so,
facing increasing heat and drag. And high temprateure materials to do
this may or may not be rather expensive...

You mean that if a scramjet is breathing oxygen as it cruises at MACH 10 in
the upper atmosphere and it suddenly pulls up, then the scramjet will come
to a
sudden and instantaneous stop once it reaches an altitude where it can no
longer pull in enough oxygen to ignite all of its fuel? Would that be like
crashing into the ground at MACH 10, by any chance?

No, he means no matter what speed you reach with a SCRAM you can only reach
that speed in the atmosphere with all the drag involved to that point. There
are no saving reaching that point in a atmosphere and you still need a rocket
to get up to orbital speed.

There is a little thing called momentum, a lack of oxygen or vacuum is not
going to bring the scramjet to a sudden halt. Gravity will slow it down,
but
only its upward component at a rate of 9.8 meters per second squared.

And all the air drag involved as it climbs, at those speeds that drag is
still a major factor.

Earl Colby Pottinger

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