Re: Hybrid Propellant Concept

Stephen Holden wrote:
> Hello,
> I am developing a new hybrid propellant concept that I would like to 
> discuss...It's basically very similar to any hybrid, except that the 
> propellant consists of a cylindrical grain of lightly bonded magnesium 
> powder onto which is sprayed through injectors the oxidizer. The 
> oxidizer is a solution of water and various nitrates and perchlorates 
> at high concentrations. There are many possibilities for testing and 
> would like to get people together to explore the concept.
> 
> I have placed a brief description on the Australian Experimental web 
> site, which I will update with any developments made.  
> 
> The motor is a concept at this stage, but tests of the reactivity of 
> lightly bonded magnesium powder and water / oxidizer solutions indicate 
> a highly energetic reaction that with a little luck will produce a 
> workable hybrid propellant.
> 
> Any and all ideas and help is welcome...I think it's an interesting 
> idea worth some investigation...
> 
> Anyways, cheers from Australia, Stephen

Somewhere, lost in the mists of time, I heard about somebody who 
made an aluminum-water hybrid using aluminum foil wrapped around a 
mandrel as the fuel grain, straight water as the oxidizer.  I 
believe he used some sort of glue on the foil to prevent wholesale 
shredding.  The poor thermal conductivity and adhesion between 
sheets helped promote ablation rather than bulk melting.

If you look at the energetics of Al/H2O, you'll see that you really 
don't need a better oxidizer.  Ignition may be tough, though- 
perhaps an innermost layer of sodium or lithium foil would work.

-- 
Doug Jones, Rocket Engineer
XCOR Aerospace
POB 1163
Mojave CA 93502
(661) 824-4714