Rocket Propellant (RP)
From PyroGuide
RP propellant is an effective rocket propellant for small rockets which produces an interesting tail effect. The image on the right is a close up of the finished product in which you can see (by clicking on the thumbnail image) the tiny specs of pyro aluminium.
Composition
| Potassium nitrate | 18 |
| Charcoal (airfloat) | 6 |
| Sulphur | 3 |
| Aluminium (-325 mesh, spherical) | 2 |
Method
Individually grind all chemicals as fine as possible (except the aluminium), using a coffee grinder or mortar and pestle (the finer the powder is, the faster it will burn). Ball mill the potassium nitrate, charcoal and sulfur for at least two hours.
Screen the aluminium into the meal using the screen method until the mixture is homogeneous. The meal may be used as is, but it is preferable to moisten with a 25% solution of alcohol, knead and force through a 20 mesh screen to granulate it. This granulation procedure makes it much easier to work with while loading into cases and also makes is somewhat more powerful.
To do this mix up a solution of about 75% water and 25% isopropyl alcohol (do not add any more than 25% alcohol). The alcohol makes the water wetter by breaking down the surface tension of the composition and allows the water to be absorbed easier. The drying time of a composition is also reduced as alcohol evaporates faster than water.
Add some of the solution to the composition and mix well. Keep adding until it is damp enough to clump together if you squeezed an amount in your hand. Don't make the mixture too wet or it will make granulating the composition impossible. If this happens, just add more dry mix.
Summary
The spherical aluminium is not for effect, but it rather a phlegmatizer. It does produce an interesting tail effect, which is probably a glitter related reaction despite the fairly low sulfur content. It burns more rapidly compared to standard meal powder and is an effective rocket propellant, especially in smaller rockets.
Video
Glitter tail rocket - 1221k - A small rocket loaded with RP propellant and small report payload. In this example you can see the bright white flashes in the tail.