Beach Shoot #3 - James Yawn Style Rocket

Date: 2003-09-03


Rcandy style propellant, with a twist. I prepared it using gum arabic instead of dextrose. The syrup he uses is probably largely vegetable gum as well as water and dextrose, so I thought it was worth a shot (to improve the casting properties).

However, I cooked it too long and it turned into a cookie like material with lots and lots of bubble voids. On testing a small chunk took off over my head out of the sink. It really burnt fast and violent at 1 atm.

As a quick test I crushed some and packed the powder into an Al foil tube, Yawn style, it had a cavity running the length of the 'grain' into which I placed a meal-NC tissue paper fuse and twisted the foil around to form a nozzle.


Little or no trust.

The rocket sat around for three days, it may have become moisture tainted as other sugar based devices have in the past. Considering how violent the fresh powder was I am pretty sure that must have been the case.

On the video you are barely see or hear the burn, it was that feeble. It looked just like a hang-fire but the propellent did actually ignite.. The rocket didn't even move on the launch tube, the motor just sat and smoked for several seconds.

Once I took it apart I was suprised to find the inside of the case lined with a white-grey glassy residue. It formed an excellent cast of the inside of the case, showing an almost perfect 45 degree convergence cone and 15 degree divergence cone. Not that it was really important for such a trivial motor, but it is interesting that such a simple construction technique can provide fairly good geometries.


title type size
Burn Video video/x-msvideo 1.245 Mbytes
Pre-Launch Photo image/jpeg 65.100 kbytes
Propellant Picture image/jpeg 60.323 kbytes
Post-Mortem Picture image/jpeg 52.840 kbytes