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Turbo Scram
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Rand Simberg
science forum beginner


Joined: 02 May 2005
Posts: 18

PostPosted: Sun Jun 18, 2006 5:07 pm    Post subject: Re: Turbo Scram Reply with quote

On 18 Jun 2006 09:24:07 -0700, in a place far, far away, "Bret Cahill"
<BretCahill@aol.com> made the phosphor on my monitor glow in such a
way as to indicate that:

Quote:
For a recoverable craft [single stage ground take off and landing
hypersonic flight] a conventional gas turbine jet engine could be
mounted inside an annular scram inlet. The gas turbine would get it up
to Mach 3 +, then shut down and the scram would take over.

A spike could pinnochio out of the GT nose cone at higher speeds to
position the shock wave into the inlet.

Three good first-order rules of vehicle design:

1) To cruise, use an airbreather
2) To accelerate, use a rocket
3) To turn, use a wing
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Ed Ruf (REPLY to E-MAIL1
science forum beginner


Joined: 03 Dec 2005
Posts: 46

PostPosted: Sun Jun 18, 2006 5:54 pm    Post subject: Re: Turbo Scram Reply with quote

On 18 Jun 2006 09:24:07 -0700, in sci.engr.mech "Bret Cahill"
<BretCahill@aol.com> wrote:

Quote:
For a recoverable craft [single stage ground take off and landing
hypersonic flight] a conventional gas turbine jet engine could be
mounted inside an annular scram inlet. The gas turbine would get it up
to Mach 3 +, then shut down and the scram would take over.

A spike could pinnochio out of the GT nose cone at higher speeds to
position the shock wave into the inlet.

I would suggest you need to investigate the concept of cowl drag and why
concepts after the NASA Hypersonic Research Engine (HRE
http://hapb-www.larc.nasa.gov/Public/Engines/Hre/Hre.html) no longer where
of the podded type design, going to the airframe integrated scramjet
concept such as the X-43A demonstrated in flight.
--
Ed Ruf (Usenet2@EdwardG.Ruf.com)
http://edwardgruf.com/Digital_Photography/General/index.html
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Sun Jun 18, 2006 6:27 pm    Post subject: Re: Turbo Scram Reply with quote

Quote:
Three good first-order rules of vehicle design:

1) To cruise, use an airbreather
2) To accelerate, use a rocket

It might be cheaper to replace the GT with a rocket and use a parachute
to land.

Quote:
3) To turn, use a wing

I wasn't thinking about doing a lot of turning. The engine would be
the craft. Any payload would be located in the nose cone spike.

We're just looking for the cheapest recoverable test rig to experiment
with scrams.


Bret Cahill
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Rand Simberg
science forum beginner


Joined: 02 May 2005
Posts: 18

PostPosted: Sun Jun 18, 2006 6:33 pm    Post subject: Re: Turbo Scram Reply with quote

On 18 Jun 2006 11:27:55 -0700, in a place far, far away, "Bret Cahill"
<BretCahill@aol.com> made the phosphor on my monitor glow in such a
way as to indicate that:

Quote:
Three good first-order rules of vehicle design:

1) To cruise, use an airbreather
2) To accelerate, use a rocket

It might be cheaper to replace the GT with a rocket and use a parachute
to land.

3) To turn, use a wing

I wasn't thinking about doing a lot of turning. The engine would be
the craft. Any payload would be located in the nose cone spike.

We're just looking for the cheapest recoverable test rig to experiment
with scrams.

That's fine, as long as you have some use for scrams that doesn't
involve going to orbit. They're not particularly useful for that.
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Ed Ruf (REPLY to E-MAIL1
science forum beginner


Joined: 03 Dec 2005
Posts: 46

PostPosted: Sun Jun 18, 2006 6:49 pm    Post subject: Re: Turbo Scram Reply with quote

On 18 Jun 2006 11:27:55 -0700, in sci.engr.mech "Bret Cahill"
<BretCahill@aol.com> wrote:

Quote:
We're just looking for the cheapest recoverable test rig to experiment
with scrams.

Out of curiosity, who are we?
--
Ed Ruf (Usenet2@EdwardG.Ruf.com)
http://edwardgruf.com/Digital_Photography/General/index.html
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Mon Jun 19, 2006 2:22 am    Post subject: Re: Turbo Scram Reply with quote

Quote:
Out of curiosity, who are we?

"We, the People" who fund NASA.

Fourth of July is coming up. People need to know that the 4th is about
using force to take geo resources and confer control of all national
economic policy to the people.

The _New York Times_ has good science writers but their Op Ed types
want everyone to believe Pat Robertson came over on the Mayflower and
the banking acts of 1913 -- the Federal Reserve has unbridled
discretion to say "surprise, I'm raising interest rates" -- trump Art.
1, Sec. 8 of the U. S. Constitution.

That's pure bullshit and the _Times_ ain't gonna get away with it..


Bret Cahill
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Ed Ruf (REPLY to E-MAIL1
science forum beginner


Joined: 03 Dec 2005
Posts: 46

PostPosted: Mon Jun 19, 2006 9:22 am    Post subject: Re: Turbo Scram Reply with quote

On 18 Jun 2006 11:27:55 -0700, in sci.engr.mech "Bret Cahill"
<BretCahill@aol.com> wrote:

Quote:
We're just looking for the cheapest recoverable test rig to experiment
with scrams.

To test exactly what in flight which can't be tested on the ground?
--
Ed Ruf (Usenet2@EdwardG.Ruf.com)
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Fred J. McCall
science forum beginner


Joined: 17 Apr 2005
Posts: 8

PostPosted: Mon Jun 19, 2006 12:47 pm    Post subject: Re: Turbo Scram Reply with quote

"Ed Ruf (REPLY to E-MAIL IN SIG!)" <egruf_usenet2@cox.net> wrote:

:On 18 Jun 2006 11:27:55 -0700, in sci.engr.mech "Bret Cahill"
:<BretCahill@aol.com> wrote:
:
:>We're just looking for the cheapest recoverable test rig to experiment
:>with scrams.
:
:To test exactly what in flight which can't be tested on the ground?

Uh, how would you go about testing a scramjet on the ground, Ed?

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Mon Jun 19, 2006 6:10 pm    Post subject: Re: Turbo Scram Reply with quote

Quote:
:>We're just looking for the cheapest recoverable test rig to experiment
:>with scrams.

:To test exactly what in flight which can't be tested on the ground?

Uh, how would you go about testing a scramjet on the ground, Ed?

Possible but very expensive:

Mount layers upon layers of bearings on a several mile diameter
circular track so the DIN number of the bearings is never exceeded --
maybe 1 layer of bearings per 300 m/sec velocity.

You can do anything with enough bearings. GE once built a 4 spool
engine which is where I got the idea.

Quote:
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

The converse isn't necessarily true. Every unreasonable man doesn't
necessarily get results.


Bret Cahill
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Ed Ruf
science forum beginner


Joined: 19 Jun 2005
Posts: 40

PostPosted: Mon Jun 19, 2006 6:23 pm    Post subject: Re: Turbo Scram Reply with quote

On Mon, 19 Jun 2006 12:47:04 GMT, in sci.engr.mech Fred J. McCall
<fmccall@earthlink.net> wrote:

Quote:
"Ed Ruf (REPLY to E-MAIL IN SIG!)" <egruf_usenet2@cox.net> wrote:

:On 18 Jun 2006 11:27:55 -0700, in sci.engr.mech "Bret Cahill"
:<BretCahill@aol.com> wrote:
:
:>We're just looking for the cheapest recoverable test rig to experiment
:>with scrams.
:
:To test exactly what in flight which can't be tested on the ground?

Uh, how would you go about testing a scramjet on the ground, Ed?

http://hapb-www.larc.nasa.gov/Public/Facilities/hapb_facilities.html
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Ken S. Tucker
science forum Guru


Joined: 30 Apr 2005
Posts: 1230

PostPosted: Mon Jun 19, 2006 6:45 pm    Post subject: Re: Turbo Scram Reply with quote

Bret Cahill wrote:
Quote:
:>We're just looking for the cheapest recoverable test rig to experiment
:>with scrams.

:To test exactly what in flight which can't be tested on the ground?

Uh, how would you go about testing a scramjet on the ground, Ed?

Possible but very expensive:

Mount layers upon layers of bearings on a several mile diameter
circular track so the DIN number of the bearings is never exceeded --
maybe 1 layer of bearings per 300 m/sec velocity.

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

only transferred heat to air via a heat exchanger,
ie. Heat Exchanging RAM jet or HERAM jet.

Cooler air enters, passes over a white hot surface
and exits with a larger volume, effectively exploding
the air as the air heats, the exploding air providing
the thrust via a divergent nozzle.
That can be done with chemical propellants too.
Pluto proved all that.

The HERAM needs about Mach 1 to effectively
provide acceleration. So the 1st stage is some
small SRB's, and the HERAM becomes the
critical 2nd stage, getting some serious Mach's
up to the upper atmosphere, then a 3rd pure
rocket stage does the final orbital insertion.
That's a cheap launch because the HERAM
can be returned, however if the HERAM is
nuclear powered it can function as the 3rd
stage (Turbo-rocket theory), which might be
even cheaper.
Regards
Ken S. Tucker
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tadchem
science forum Guru


Joined: 03 May 2005
Posts: 1348

PostPosted: Mon Jun 19, 2006 9:28 pm    Post subject: Re: Turbo Scram Reply with quote

Bret Cahill wrote:
Quote:
:>We're just looking for the cheapest recoverable test rig to experiment
:>with scrams.

:To test exactly what in flight which can't be tested on the ground?

Uh, how would you go about testing a scramjet on the ground, Ed?

Possible but very expensive:

Mount layers upon layers of bearings on a several mile diameter
circular track so the DIN number of the bearings is never exceeded --
maybe 1 layer of bearings per 300 m/sec velocity.

Alternative static testing method:

....put it in a hypersonic wind tunnel...

Also very expensive

Tom Davidson
Richmond, VA
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Mon Jun 19, 2006 9:50 pm    Post subject: Re: Turbo Scram Reply with quote

Quote:
only transferred heat to air via a heat exchanger,
ie. Heat Exchanging RAM jet or HERAM jet.

Cooler air enters, passes over a white hot surface
and exits with a larger volume, effectively exploding
the air as the air heats,

What's the heat transfer coefficient? There isn't any great increase
in the Nu number going from subsonic to supersonic flow.

I once did some calculations on a solar powered ram trying everything
from mile long craft to flat panels of engines but could never get
enough energy density (although heat transfer wasn't the problem).


Bret Cahill
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Ed Ruf (REPLY to E-MAIL1
science forum beginner


Joined: 03 Dec 2005
Posts: 46

PostPosted: Mon Jun 19, 2006 10:30 pm    Post subject: Re: Turbo Scram Reply with quote

On 19 Jun 2006 14:28:42 -0700, in sci.engr.mech "tadchem"
<tadchem@comcast.net> wrote:


Quote:
Alternative static testing method:

...put it in a hypersonic wind tunnel...

Also very expensive

What's very expensive compared to trying to flight test something? Freejet
facilities all ready exist in this country at NASA LaRC and GRC, AEDC,
ATK-GASL. Direct-connect facilities at LaRC, GRC, GASL, AFRL. even UVA.
Pulsed facilities at LaRC/GASL, Calspan, Cal-tech. et alone others around
the world. You get what you pay for. Ground test articles tend to have much
more instrumentation on them, so you can actually learn much more from the
tests. Let alone run repeated tests. No matter how you slice it duplicating
the total energy of Mach 5+ flight isn't cheap no matter how you do it.
--
Ed Ruf (Usenet2@EdwardG.Ruf.com)
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Mon Jun 19, 2006 10:52 pm    Post subject: Re: Turbo Scram Reply with quote

They keep saying the physics of scram is understood well enough, that
it's "merely an engineering problem."

Of course, that's what they keep saying about nuclear fusion so it may
be a meaningless statement.


Bret Cahill
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