Hypersonics Overhype

"Uddo Graaf" wrote

"Rand Simberg" wrote

That's the theme of my latest column at TechCentralStation:

http://www.techcentralstation.com/033104C.html

Most excellent. I agree that feeling out the possibilities of
scramjets is worth doing, whether by the military or a NACA-ized
NASA. But a lot of what's been said about Hyper-X reminds me of
the hype about ISS/STS science. Way premature, at best.

(I also think that finally getting some experimental aerospikes
flying is worth doing, but that's another discussion.)

I myself even have doubts about the military applications for the hypersonic
bomber the Air Force is envisioning. The goal is to have almost zero
decision-to- impact time but a hypersonic vehicle can hardly loiter around
and would probably have a huge turning circle travelling at its minimum
speed (mach 5). It would take about 10 minutes to get a bomb on target by
such as bomber after the 'go' was given. This compares unfavourably compared
to a ICBM which can hit any target in the world in 15-20 minutes. A modified
ICBM with a conventional warhead would probably be just as effective.

Yeah. Again, it's worth doing some R&D, but you do wonder why
a scramjet is better than a rocket for the time-urgent Osama-
blowing-up mission. A rocket -- like Pegasus -- could be launched
from the same aircraft as the scramjet if you didn't want to use an
ICBM.

Ed Ruf wrote:

On 31 Mar 2004 22:13:46 GMT, in sci.space.policy
(TKalbfus) wrote:

How about a maglev launched Scramjet? Just build a short maglev track, (The
Chinese have one), that can accelerate the maglev to 7 times the speed of
sound. The scramjet then takes off from that, flies to orbit and then glides to
a runway landing.

You must be a heat transfer or TPS guy looking for work. :-)
Seriously, M=7 on the deck is q = 70,000psf! 70 times that at 95kft.

Didn't the folks at Holloman AFB get their mag-lev rocket sled to M8+,
at least for a second or so?

h (Rand Simberg) wrote:

On Wed, 31 Mar 2004 13:08:02 -0800 (PST), in a place far, far away,
(Rand Simberg) made the phosphor on my
monitor glow in such a way as to indicate that:

If a NASA PAO generated the same statement about X-43A, you'd be among
the first to crawl all over them for making a 'failure' a 'sucess'.

If I had been aware, yes. I'll research further and see if I can
rectify it. Thanks for the correction.

OK, Derek, you're going to have to provide a cite for your claim,
because I can't find any references to it. Everything I find
indicates a test success.

I can't find my reference, it wasn't widely reported. I'll keep
digging. (And hopefully not a hole.)

Even so, the Australian team with it's tiny fraction of the Hyper-X
budget accomplished only a fraction of what the Hyper-X did. They
demonstrated ignition and combustion, not flight. (The HYSHOT test
vehicle was essentially falling in a near vertical trajectory, not
free flight.) Even they themselves describe the test as one of
'hypersonic combustion'
(http://www.space.com/missionlaunches/hyshot_020816.html) not
'hypersonic flight'.

D.
--
Touch-twice life. Eat. Drink. Laugh.

Rand Simberg wrote:

On Wed, 31 Mar 2004 13:08:02 -0800 (PST), in a place far, far away,
h (Rand Simberg) made the phosphor on my
monitor glow in such a way as to indicate that:

If a NASA PAO generated the same statement about X-43A, you'd be among
the first to crawl all over them for making a 'failure' a 'sucess'.

If I had been aware, yes. I'll research further and see if I can
rectify it. Thanks for the correction.

OK, Derek, you're going to have to provide a cite for your claim,
because I can't find any references to it. Everything I find
indicates a test success.

The ABC thinks it was a success:

http://www.abc.net.au/science/slab/hyshot/default.htm
#begin quote
did the test go?

On July 30, 2002 the University of Queensland HyShot team culminated
many years of work when they sent their second scramjet payload up into
the atmosphere on the back of a Terrior Orion rocket in a test flight.
They made history - it turned out to be the first successful launch of a
scramjet in the world.


The staged Terrier Orion rocket and UQ payload on the launch pad at
Woomera. (Courtesy: The University of Queensland.)
The dramatic TV footage of the Orion-Terrier rocket actually doesn't
show the scramjet working - the rocket is simply there to get the
scramjet up into the air and moving quickly. The two-stage rocket used
aluminium powder and ammonium dichromate, solid fuel like a Lilliputian
Titan 4, to send the payload right up into space, to 314 kilometres.

The timing of the launch had to fit around what else was out in orbit.
At one stage they had to wait because the projected path of the rocket
was within a few thousand metres of the orbit of an American satellite -
too close to take any risks!

On the day, everything went to plan. The first stage rocket burned for
six seconds, accelerating the craft to Mach 3.6, or 3.6 times the speed
of sound. That ran up the sky, leaving a white trail behind that stopped
halfway up the sky, and then the roar reached us, standing out on the
plain, several kilometres away.

This was a 16-second silent pause while the slim second stage and the
payload slipped free of the spent initial stage. The second stage sits
on top of the first stage, and simple drag caused the first stage to
fall behind.

The business end, the slimmer second stage and its payload, coasted
upwards, losing speed from Mach 3.6 back down to Mach 3.2, stabilising
any flutters from the first blast. It also pushed through the worst of
the lower atmosphere before the second stage rocket kicked in, high in
the sky, boosting it up to Mach 7.7.

The second rocket blast took it to 56 kilometres above the Earth, just
39 seconds after the scramjet took off. It then simply coasted to the
top of the parabola. This is 'going ballistic' in the scientific form of
the word.

When it levelled out it had been flying for just over four-and-a-half
minutes. Gravity kicked in and it tilted and began to plunge back to the
atmosphere. By the time the turn was completed, three minutes later, it
was almost halfway down to the ground again.

We have scramjet!


Oh, what a feeling... members of the successful HyShot team (from left)
Judy Odam, Dr Ross Paull, Bert Paull, Dr Allan Paull, Dr Susan Anderson,
Myles Frost, Suhee Won and Aggie Branczyk. (Courtesy: The University of
Queensland.)
As the air thickened, the rocket and the passenger scramjet slowed to
Mach 7.6, and more oxygen began to pass through the system.

At 35 km up in the air - about three times the height jetliners fly at -
the scramjet kicked in, just as it disappeared over the horizon, as seen
from the control block.

The payload was sending data back to receivers on Earth from 40 channels
different channels including pressure readings, temperature readings,
acceleration measurements and magnetometer readings.

The rocket flew as it should, and the scientists tracked it down range
and retrieved the telemetry back from the other end to make sure that
everything went to plan. The remote stations were in contact with the
base by satellite phone, and so the remote stations knew where to point
their equipment in order to find the craft as it hurtled towards them at
Mach 7.6.

So from a first generation of toxic rockets to a generation of slightly
less toxic reusable craft like the Shuttle, now we are turning to the
third generation of space lift, in the form of a scramjet.

The scramjet flew for just six seconds, but then the first flight by the
Wright Brothers only lasted 12 seconds, and Robert Goddard's first
rocket flight in 1926 lasted just 2.5 seconds, so that would seem to
place the scramjet in the middle of the duration span for historic space
and flight exploits.

Certainly, as one of the University of Queensland people told me over
dinner when I mentioned Jonathan Swift, the achievement was by no means
Lilliputian.

History will be the judge, but I agree.
#end quote

On Wed, 31 Mar 2004 18:03:19 -0800 (PST), in a place far, far away,
(Derek Lyons) made the phosphor on my
monitor glow in such a way as to indicate that:

OK, Derek, you're going to have to provide a cite for your claim,
because I can't find any references to it. Everything I find
indicates a test success.

I can't find my reference, it wasn't widely reported. I'll keep
digging. (And hopefully not a hole.)

Even so, the Australian team with it's tiny fraction of the Hyper-X
budget accomplished only a fraction of what the Hyper-X did. They
demonstrated ignition and combustion, not flight. (The HYSHOT test
vehicle was essentially falling in a near vertical trajectory, not
free flight.) Even they themselves describe the test as one of
'hypersonic combustion'

Well, hypersonic combustion is hypersonic combustion. Sounds like
scramjet in flight to me. That's no in conflict with my column.

I remain willing to correct it, but you've got to provide some reason
to do so other than, "Derek Lyons says."

Derek Lyons wrote:

"Uddo Graaf" wrote:


I myself even have doubts about the military applications for the hypersonic
bomber the Air Force is envisioning. The goal is to have almost zero
decision-to- impact time but a hypersonic vehicle can hardly loiter around



Why not?


I think it's far more likely to end up as a propulsion system for a
missile rather than a manned bomber- we've probably already done work on
a rocket-boosted silo-launched scramjet cruise missile under the "Teal
Dawn" program.
(whatever "Teal Dawn" was, it was supposed to come out of a Minuteman
silo, be stealthy, have a range of around 6,000 miles, and apparently
worked... it's listed as a "past success" he
http://www.dtic.mil/labman/projects/lqip/dsb/dsb3.html ....it is also
just about impossible to find information on, even though it was
scheduled for operational deployment in the late 1990's)

Pat

Pat Flannery wrote

I think it's far more likely to end up as a propulsion system for a
missile rather than a manned bomber- we've probably already done work on
a rocket-boosted silo-launched scramjet cruise missile under the "Teal
Dawn" program.
(whatever "Teal Dawn" was, it was supposed to come out of a Minuteman
silo, be stealthy, have a range of around 6,000 miles, and apparently
worked... it's listed as a "past success" he
http://www.dtic.mil/labman/projects/lqip/dsb/dsb3.html ....it is also
just about impossible to find information on, even though it was
scheduled for operational deployment in the late 1990's)

Could you post the source of the above, please? I didn't find it
in a quick look around, but this did come up:


From Jim Karam's page, http://www.karam.com/Photo_Gallery_Core.htm

[Picture of] Convair's AGM-129A Advanced Cruise Missile, a
direct descendant of one of my DARPA initiatives that was
nick-named Teal Dawn[*]. Gee, I wonder where he came up
with that name? And, no, this picture is not upside-down
and backward. Also, don't let anyone tell you how easy it
is to design forward swept wings because of today's powerful
analytic software.
[*] points to picture of his daughter, Dawn

Which his resume http://www.karam.com/Jim_Karam's_Resume.htm
dates:

Program Manager, Strategic Technology Office, Defense Advanced
Research Projects Agency, Rosslyn, VA (1975-1978)

Conceived & executed three major advanced cruise missile
technology thrusts (approx. $15M annually). "Zero-CEP" guidance
incorporated active (laser & mmw) & passive sensors with
sophisticated image processing. Demonstrated compound rotary
and reciprocating engine concepts for reduced fuel consumption,
small propulsion. More survivable airframes used radical shaping
and new advanced materials, i.e., the beginnings of "stealth".
Several eventually entered Full Scale Development and/or
production by the Air Force and Navy.

There's also a short write-up on pdf p.73 of
http://www.darpa.mil/body/pdf/transition.pdf

ADVANCED CRUISE MISSILE

A DARPA program, TEAL DAWN, developed key technologies
and a design later incorporated into the Air Force Advanced
Cruise Missile (ACM). In the early 1980s, the Air Force
assumed responsibility for the ACM Program and successfully
managed the system through concept demonstration; engineering
and manufacturing development; production; and development.

The TEAL DAWN Program involved a series of studies and
developments related to the development of a long-range
stealthy strategic cruise missile. DARPA experience in
low observables was incorporated into the design of the
low-signature engine inlet and nozzle. Other technologies
included the unique aerosurface sweep angles that provided
a benefit to the aerodynamic performance.

Clearly recognized performance goals (signature, range,
flight profile)were successfully demonstrated during the DARPA
phase of the program. Wind tunnel and radar ranges testing
also were accomplished by the Air Force under DARPA
sponsorship. The follow-on Air Force program could then focus
on operational test and evaluations (OT&E) and manufacturing
objectives with a high degree ofconfidence that program
objectives would be realized.

A scramjet can't fly to orbit. It only works in the atmosphere.
Amazingly enough, there were people working on NASP who didn't
understand this.


I never said it could all by itself. Scramjets don't work in the vacuum of
space as they require a hypersonic flow of oxygen. At some point a rocket will
have to take over.
Still for atmospheric transport you could build a maglev launch rail that's
long enough to bring the scamjet up to sufficient speed at which it can operate
and this could be the equivalent of a hypersonic maglev that goes all the way
to the destination. I'm not sure how good a maglev rail would be at catching a
scramjet. Perhaps it would be better to let the scramjet stall and glide to a
runway landing. Perhaps ducted fans would be of help in generating lift on
runway approaches.

Tom

h (Rand Simberg) wrote:
Well, hypersonic combustion is hypersonic combustion. Sounds like
scramjet in flight to me. That's no in conflict with my column.

Only if you are willing to play word games. Hence my point about
twisting to slam NASA.

I remain willing to correct it, but you've got to provide some reason
to do so other than, "Derek Lyons says."

I'm a' working on it.

D.
--
Touch-twice life. Eat. Drink. Laugh.

On Thu, 1 Apr 2004 09:48:52 -0800 (PST), in a place far, far away,
(Derek Lyons) made the phosphor on my
monitor glow in such a way as to indicate that:

(Rand Simberg) wrote:
Well, hypersonic combustion is hypersonic combustion. Sounds like
scramjet in flight to me. That's no in conflict with my column.

Only if you are willing to play word games. Hence my point about
twisting to slam NASA.

rolling eyes

I didn't "slam NASA."