This rocket was made using the core of a calculator paper roll, which is a spiral wound tube about 50 mm long, 8 mm ID, and with 2-3 mm walls.
The nozzle was rammed cat litter. The bulkhead paper wadding and hot-melt glue. The nozzle throat was 3 mm in diameter.
The grain was two chunks of KN/Fructose/IO propellant cord, each about 15 mm long, a sliding fit with the tube ID. A 1.5 mm hole was bored up the middle of the resulting assembly as a primitive combustion cavity, but the effort seemed rather moot considering there was no inhibitor coating on the grains, they would burn on all surfaces. The mix was:
60% Potassium Nitrate
39% Fructose
1% Iron Oxide (red)
The fuse was meal-NC tissue paper which is prooving to be the most reliable kind I've ever made, I am using them almost exclusively now. There was no priming.
Reasonable flight.
Rocket took a long time to come up to pressure. It fizzled for about 2-3 seconds on the launch pad. Once it did start putting out useful thrust it made an excellent flight.
Its apogee was at least 100 metres. Higher than the sugar rocket anyway. The rocket was not recovered as again it became impossible to track after burn-out.
It may be a moisture tainted grain problem again. I was half expecting the thing to CATO from the large surface area to burn. The long build-up to pressure was concerning too. It must have spent a large amount of fuel before it even moved. Perhaps priming would help in future?
It still performed OK, but I'd like to see better acceleration and apogee next time. Similar comments about the sugar rocket, these devices have a few gramms of propellant, I would expect better performance in future.
| title | type | size |
|---|---|---|
| Rocket Launch | video/x-msvideo | 1.836 Mbytes |
| Pre-Launch Picture | image/jpeg | 52.342 kbytes |