Michael Wallis wrote:
> Alex Fraser wrote:
>
> > The catpack must catalyze the fuel. The wetted area must go up
> > to match fuel rate. Wetted area is a surface. The fuel exists as
> > a volume.
>
> Ah ... no, theat's incorrect. The cat pack catalyzes the oxidizer -
> HTP - not the fuel. The exhaust from the cat pack - pure oxygen at
> 1800 F - will ignite any hydrocarbon fuel on contact (therefor no
> ignition system is needed).
Fuel was the wrong word here. A re phrase
The catpack must catalyze the H2O2. The wetted area must go up
to match H2O2 rate. Wetted area is a surface. The fuel exists as
a volume.
>
>
> > I don't think anyone has scaled up a silver screen catpak enough
> > to really know how large they can be built. I think the larger they
> > get the harder they will be to fabricate, that is harder out of
> > proportion to size. What is the largest built to date? At what
> > diameter of screen will you need to support it in the middle?
>
> Ah ... wrong again - the Brits scaaled HTP/Kero engines to the point
> where they put a 125 kg satellite into polar orbit using a three stage
> vehicle. That sounds like a working solution.
I don't think they used a silver screen catalyst. Didn't they use "magic
rocks" in a cage?
>
>
> > As for weight if you compare multi catpac single nozzle to
> > multiple engines of the same thrust which would be lighter?
>
> Lighter isn't the sole issue. Servicability is a top consideration.
> Reliability is a top consideration. Performance of the overall vehicle
> is a top consideration. There are lots of tradeoffs - it's not a
> matter of size alone.
Yes i did mention that the catpac could be pulled without removing the
engine. I think the catpac and associated plumbing are the main
maintenance issues. For a larger engine this is a good compromise.
>
>
> Michael
>
> ----------------------------------------------------------------------
> Michael Wallis KF6SPF (408) 396-9037 [EMAIL PROTECTED]
> President, Wallis International http://www.wallis.com
>
> Coleman Orr:
> "You either drift through life, or drive through it."
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