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Pulse Detonation Engine, first stage or ..



 
 
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  #1  
Old March 31st 04, 01:24 PM
Abrigon Gusiq
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Default Pulse Detonation Engine, first stage or ..

http://www.pr.afrl.af.mil/divisions/prt/pde/index.html

Check it out, and anyone have any ways to use it as part of a Shuttle
replacement
or as part of a seperate craft that does some of the shuttles missions?

Mike
Alaska
  #2  
Old April 1st 04, 01:00 AM
Damon Hill
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Default Pulse Detonation Engine, first stage or ..

Abrigon Gusiq wrote in news:406AB84E.65B62223
@yahoo.com:

http://www.pr.afrl.af.mil/divisions/prt/pde/index.html


Unless it can be scaled up to the necessary thrust levels,
there's no chance of it being used at all. I'm not sure
how much advantage it would have over a conventional
rocket engine, as I haven't seen figures for specific
impulse--probably its only advantage, if it all.

--Damon
  #3  
Old April 6th 04, 05:50 AM
Allen Meece
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Default Pulse Detonation Engine, first stage or ..

I think the PDE will scale up to make a flyback launch assister for a CATS
SSTO.
The site says the PDE is great between 2 to 4 machs and can take off from
zero speed so it offers a lot in the way of airbreathing launchers.
^
//^\\
~~~ near space elevator ~~~~
~~~members.aol.com/beanstalkr/~~~
  #4  
Old April 7th 04, 03:23 AM
Joann Evans
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Default Pulse Detonation Engine, first stage or ..

Allen Meece wrote:

I think the PDE will scale up to make a flyback launch assister for a CATS
SSTO.
The site says the PDE is great between 2 to 4 machs and can take off from
zero speed so it offers a lot in the way of airbreathing launchers.


Who cares? Supersonic mated flight and seperation is too complex and
risky. Seperate subsonically (with existing 'first stage' aircraft, if
possible) at the highest altitude practical, to minimize drag and engine
expansion issues for your orbiter.

--

You know what to remove, to reply....

  #5  
Old April 7th 04, 11:25 PM
sanman
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Default Pulse Detonation Engine, first stage or ..

Joann Evans wrote in message ...
Allen Meece wrote:

I think the PDE will scale up to make a flyback launch assister for a CATS
SSTO.
The site says the PDE is great between 2 to 4 machs and can take off from
zero speed so it offers a lot in the way of airbreathing launchers.


Who cares? Supersonic mated flight and seperation is too complex and
risky. Seperate subsonically (with existing 'first stage' aircraft, if
possible) at the highest altitude practical, to minimize drag and engine
expansion issues for your orbiter.


Hmm, the idea does sound interesting, though. If you had a TSTO which
separated at supersonic speed very high in the atmosphere, then even
though the PDE lower stage would careen and tumble away at high speed,
the PDEs could allow it to quickly right itself to return for a
controlled landing. The whole pulsed idea seems suited for dealing
with radical chaotic motion.

But the scramjet unfortunately isn't enough to get to orbit. You'd
need further rocket propulsion to take over after the scramjet.
  #6  
Old April 8th 04, 03:58 AM
Allen Meece
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Default Pulse Detonation Engine, first stage or ..

Who cares? Supersonic mated flight and seperation is too complex and
risky. Seperate subsonically (with existing 'first stage' aircraft, if
possible) at the highest altitude practical, to minimize drag and engine
expansion issues for your orbiter.
I think the more you can accelerate an orbiter with a flyback PDE booster,
the less tankage you will need in the orbiter. That seems like square one, keep
the fuel out of the orbiter.
I doubt that booster/orbiter separation at mach 4 [PDE's max efficient
speed] will be such a big deal. It's a new thing but so what? *Everything* was
once new and baffling.
^
//^\\
~~~ near space elevator ~~~~
~~~members.aol.com/beanstalkr/~~~
  #8  
Old April 15th 04, 03:26 AM
Allen Meece
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Default Pulse Detonation Engine, first stage or ..

risky. Seperate subsonically (with existing 'first stage' aircraft, if
possible) at the highest altitude practical, to minimize drag and engine
expansion issues for your orbiter.

Yes, this is doubtlessly the best way to begin an air launch program. It's
cheaper and faster than developing a high performance PDE launcher aircraft as
well as a Dyna-Soar type of spacecraft.
And the moon ship must be lifting body, not a milk jug or the whole project
is a waste of money as far as developing CATS is concerned.

^
//^\\
~~~ near space elevator ~~~~
~~~members.aol.com/beanstalkr/~~~
  #10  
Old April 26th 04, 08:11 AM
Jake McGuire
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Default Pulse Detonation Engine, first stage or ..

(John Carmack) wrote in message . com...
I certainly agree with you regarding the value of a lifting-body, but
I would contend that there are circumstances where a single vehicle
design may still win out for moon missions. A VTVL SSTO can do the
LEO to lunar surface and back trip after refueling in orbit. While it
certainly wouldn't be optimal for it,


A VTVL SSTO has the raw delta-V capability to perform a lunar mission.

Can its main propulsion system start in zero and 1/6 g?
Can it handle the thermal environment of trans-lunar cruise?
Can it handle the thermal environment on the lunar surface?
Do its engines throttle deeply enough to allow sane lunar landing
trajectories?
Is it capable of weeks of on-orbit propellant storage?
Or weeks of on-orbit power generation?
Or a week of life support for the crew?
How will you get down to the lunar surface from the cargo/crew
compartment?

And that's only the things that I could think of faster than I could
type.

Now you could probably address most of these issues, but any SSTO is
going to be operating on a very steep part of the mass ratio curve, so
you'd probably have to address them by modifying one (or a couple)
vehicles specifically for the lunar trip. At which point it might
very well end up that the modifications would cost more than designing
an in-space transport from scratch, possibly reusing some components
(flight computers, RCS, etc) from your hypothetical SSTO.

Something that seems like a better and easier-to-make-work idea is
launching large components of a Mars mission (trans-mars cruise stage,
surface habitat, etc) on an ELV but not separating the second stage,
refueling it, and using it for trans-mars injection. The requirements
are much more alike in that case...

-jake
 




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