What is a scram Jet & how does it work

phil

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Jan 26, 2001, 8:07:49 PM1/26/01

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Just wondering on a definition in simple terms . Notice this question is
posted to THREE aviation groups

Cheers Phil
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Doug

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Jan 26, 2001, 8:07:26 PM1/26/01

to phil

http://www.google.com/search?q=scramjet

I believe that the acronym stands for supersonic combustion ram jet.

R/ Doug

Greg McFadden

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Jan 26, 2001, 8:16:05 PM1/26/01

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According to my Thermodynamics text, a scramjet is simply a ramjet where the
velocity of the air passing through the engine is always greater than the
speed of sound.

in a standard ramjet, the air flowing over the outside of the jet should be
above mach 2-3 for best use.

the air inside the ramjet is decelerated to mach 0.2 at which time fuel is
injected and the mixture detonates because by slowing the air to mach 0.2,
the air has been compressed greatly and also heated greatly.

so a scramjet is one where the air is slowed, but not past the speed of
sound in the engine.

From
Thermodynamics, third edition
ISBN 0-07-011927-9
"phil" <cle...@vianet.net.au> wrote in message
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The_Count

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Jan 27, 2001, 1:24:18 AM1/27/01

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Here's some testbed info:

"phil" <cle...@vianet.net.au> wrote in message
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>

John Keeney

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Jan 27, 2001, 3:20:58 AM1/27/01

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phil <cle...@vianet.net.au> wrote in message
news:94t6er$89a$1...@yeppa.connect.com.au...
>

> Just wondering on a definition in simple terms . Notice this question is
> posted to THREE aviation groups

Expand the acronym: Supersonic Combustion ram jet.
A ram jet where the air flow associated with fuel combustion
is supersonic.

Craig C.

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Jan 27, 2001, 9:48:49 AM1/27/01

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"John Keeney" <jdke...@iglou.com> wrote:

>
>phil <cle...@vianet.net.au> wrote in message
>news:94t6er$89a$1...@yeppa.connect.com.au...
>>
>> Just wondering on a definition in simple terms . Notice this question is
>> posted to THREE aviation groups
>
>Expand the acronym: Supersonic Combustion ram jet.
>A ram jet where the air flow associated with fuel combustion
>is supersonic.

It's a fairly simple engine from the mechanical point of view. The big
problem that everyone working on them has is keeping the combustion
process contained and steady. There has been a lot of work done in
that area over the years. I don't know if anyone has flown a test
engine other than scale models. Should be intersting when someone
finally gets it all together and working.

Craig C.

Stealth Pilot

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Jan 27, 2001, 9:59:39 AM1/27/01

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On Fri, 26 Jan 2001 17:16:05 -0800, "Greg McFadden"
<arch...@hotmail.com> wrote:

>According to my Thermodynamics text, a scramjet is simply a ramjet where the
>velocity of the air passing through the engine is always greater than the
>speed of sound.
>
>in a standard ramjet, the air flowing over the outside of the jet should be
>above mach 2-3 for best use.
>
>the air inside the ramjet is decelerated to mach 0.2 at which time fuel is
>injected and the mixture detonates because by slowing the air to mach 0.2,
>the air has been compressed greatly and also heated greatly.
>
>so a scramjet is one where the air is slowed, but not past the speed of
>sound in the engine.
>

mach 0.2 IS below the speed of sound

Greg McFadden

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Jan 27, 2001, 12:28:38 PM1/27/01

to

you didn't follow:

I was describing a Ramjet, because they are like scramjets just with
different air velocites inside the engine:

And as a side note, a scramjet only operates efficiently at very high mach
numbers, like 5+.

A RAMJET slows the air to about mach 0.2

A SCRAMJET slows the air to above mach 1.0

"Stealth Pilot" <tail...@eyeeyenetblotnetblotau.useless.decoys> wrote in
message news:3a72e214...@news.iinet.net.au...

Stealth Pilot

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Jan 28, 2001, 1:38:24 AM1/28/01

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On Sat, 27 Jan 2001 09:28:38 -0800, "Greg McFadden"
<arch...@hotmail.com> wrote:

>you didn't follow:
>
yep, missed the missing sc.

>> >the air inside the ramjet is decelerated to mach 0.2 at which time fuel

jacko

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Jan 31, 2001, 7:47:51 AM1/31/01

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In article
<3ED12179F886D76A.12197BFB...@lp.airnews.net>,

valc...@dhc.net (Craig C.) wrote:
>
> It's a fairly simple engine from the mechanical point of view. The big
> problem that everyone working on them has is keeping the combustion
> process contained and steady. There has been a lot of work done in
> that area over the years. I don't know if anyone has flown a test
> engine other than scale models. Should be intersting when someone
> finally gets it all together and working.
>

Maybe I'm stating the obvious - but University of Queensland is
planning a vertical test of a scramjet at Woomera - a Google on Project
Hyshot should give results I think.

jacko

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Phil C

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Jan 31, 2001, 10:41:43 AM1/31/01

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Thanks Jacko -interesting bit of theorem beginning to get real and
hopefully commercial

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Nathan Long

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Jan 31, 2001, 5:53:05 PM1/31/01

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Are they going to use the multistaged Zunis? Or has that project fallen by
the wayside?

Nathan

"jacko" <jac...@my-deja.com> wrote in message
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Craig C.

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Jan 31, 2001, 7:24:55 PM1/31/01

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jacko <jac...@my-deja.com> wrote:

>Maybe I'm stating the obvious - but University of Queensland is
>planning a vertical test of a scramjet at Woomera - a Google on Project
>Hyshot should give results I think.
>

Thanks for the update Jacko....I don't see as much of the research
stuff as I used to...been out of the transonic/hypersonic testing
business for about 15 years now.

Craig C.

jacko

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Feb 1, 2001, 7:23:24 AM2/1/01

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In article
<9809DBDAE3C63BDD.C09E558E...@lp.airnews.net>,

valc...@dhc.net (Craig C.) wrote:
> Thanks for the update Jacko....I don't see as much of the research
> stuff as I used to...been out of the transonic/hypersonic testing
> business for about 15 years now.
>

Me too - ever since a ham-fisted Cuban 8 in a Chippie finished up as
more like a figure 9 :-)

valc...@dhc.net

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Feb 1, 2001, 6:36:33 PM2/1/01

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Ouch.......I've lost friends to things like that....I got out of the
business when I had to go back to work to pay the bills....living off
of a temporary retirement fund at 22, and you't be suprized how fast
the buck flow out. After 4 years of negative cash flow, I had to go
back to work for real.

Craig C.