This static test was to assess the suitability of a plaster nozzle which was cast in place in the tube using a simple jig.

The jig consists of a plate of HDPE with 4 holes drilled in it. Bolts are screwed through the holes in a self tapping manner. 3 of the bolts are arranged in a triangular formation to securely hold the cardboard tube. The third bolt is located in the centre of the triangle. Plaster is poured into the tube and allowed to set. The centre bolt is removed via simply unscrewing leaving the nozzle hole in the plaster.

The rocket was packed with a rough KNO3 + sucrose fuel powder, and the engine rear sealed using a plug carved from low density ceramic furnace brick hammered in place.

The nozzle performed perfectly and was intact with no detectable damage after the test.

The failure of the rocket was due to the ejection of the rear plug.

The burn was a success because the part being tested (the cast plaster exhaust nozzle) functioned as desired:
Withstood internal engine pressure.
No significant damage.
No significant change in the exhaust nozzle diameter.

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