Re: HOW TO BUILD ROCKET ENGINE OF SOLID FUEL

Dear User,

For once, I am delighted to hear that "...it was very difficult to obtain 
even these simple chemical...". If you're moderately lucky you might just 
escape with your eyebrows singed, and lungs full of (mildly carcinogenous) 
products of incomplete combustion of sugar. If you are very lucky, however, 
then you may end up with your eyes full of liquified, burning mixture of 
sugar and KNO3. Delight family and friends for years to come. Cool !

Seriously now...

If you need to make "candy propellant" there are a couple of sites on the 
internet which give precise instructions. I would not point you to them 
because they are within 1 step search from altavista or yahoo. This 
propellant is very weak, and is quite tolerant to deviations in ratio of 
the mixture, so most likely the problem which you're facing is not related 
to the composition but to the design of your engine. 

Candy propellant is a very weak one. It would not work unless it is 
confined very accurately and very tightly. You ask why should there be a 
"hole" in the centre of the engine. The "hole" is properly called the 
"soul" of the rocket. It provides extra surface, which when the engine is 
ignited grows rapidly. Thus, the amount of gas per second is higher and the 
build-up of pressure is much more rapid. The engine is "choked" by a 
carefully constructed plug, with a small hole in it -- the nozzle. Internal 
pressures may reach hundreds of atmospheres.

I am sorry to say but for an unexperienced person, candy propellant may 
prove to be quite a challenge. It is weak and hygroscopic, and when wet it 
can be very unpredictable. Commercial rocket engines usually employ a 
variant of black powder, which is moistened and pressed into the cardboard 
hulls (walls must be thick enough to withstand the pressure, so cardboard 
rolls won't do). Nozzles are either made of clay, or , in advanced models, 
from ceramics or graphite. 

I would advise you to research the internet, or better, the library before 
undertaking any further tests. For additional information, please contact 
me directly.

A.G.E.

Rocket engine building, even on a model scale, is a very serious 
undertaking. I cannot possibly