Model Forum / General / Rockets / March 2006

if you see the nitrates anywhere, let me know ok :) the carbonates are
good, but not nearly as versatile.

Designing your own rockets from scratch can be an incredibly difficult
but satisfying thing to do, and one of the most technical and rewarding
things you can do is engine design. Different fuels/compositions
require different nozzling, different powder core depth, different
casing because of varying temperatures/pressures, the list goes on :)
For some people, simply launching or just designing the rocket casing
isn't enough of a real experience. These are the people you know who
always create the elaborate multiple engine, multistage rockets. Engine
design is simply the next step.

Black powder is a great fuel. In fact, your estes engines all use it.
For those of you who are interested, the estes c-class engine formula
is:

Source: rec.pyrotechnics, Composition from 1994 US Dept. of Labour
Material Safety Data Sheet.

Potassium nitrate.................................71.79
Sulfur............................................13.45
Charcoal..........................................13.81
Dextrin...........................................0.95

This formula is parts by weight. The standard BP formula is:

Potassium nitrate.................................75
Charcoal..........................................15
Sulfur............................................10

These formulas will only work correctly if ball milled for at least 2
hours. 3 if possible.

Because of the constant media-hyped events over the last couple of
years, making your own black powder can draw a frown of two. In fact,
if I go out and tell someone I meet that I make black powder, they give
me the strangest look - right until I tell them it's for my model
rocketry - then it's all smiles. Seriously though, it's not real wise
to go out and and make a whole batch of black powder just to
"experiment". For those who would like to begin making their own
engines, the first thing they should do is get started reading about
basic rocket engine. Believe it or not, some of the best material I've
ever read has come from pyrotechnics websites. They usually have a
small section about basic rocket engine design so that those wishing to
make skyrockets can first begin by learning how to make the rocket part

This guy has a brilliant site:
http://www.wfvisser.dds.nl/indexEN.html

His BP rocket section is here:
http://www.wfvisser.dds.nl/EN/rockets_BP_EN.html

After learning basic rocket design, I recommend going out and becoming
a member of a local hunting club and obtaining a category A firearms
licence (Australia). After you have the licence, you are then free to
purchase commercial grade FFFFg black powder which you can begin
packing your own engines with perfectly legally. If you wish to go a
little further and make your own powder, you should obtain an
unsupervised handling licence, followed by a permit to manufacture from
workcover. As far as making BP with only a firearms licence, well, ask
at your local police station if it's allowed in your state or
territory.

Safe Rocketry Guys!
-Adam