Beach Shoot #9 - Core-Burning Rockets

Date: 2003-11-04


Two motors, a test of the 9.5 mm ID, 50 mm long tubes. Both were rammed with RP on a nipple alone, the cores drilled out with different diameter drills (1.8 mm and 2.5 mm) to tune the motor.

Wax treated cat litter was used for the nozzles and bulkhead, each about 10 mm thick. Leaving 30 mm of grain length. The core was drilled to a depth of 20 mm into each grain.


One great flight, one CATO.

The first device tested was the 2.5 mm core, I figure if it exploded I was seriously wrong somewhere and could drill-out the 1.8 mm core and try again. The 2.5 mm core/nozzle device flew wonderfully, hundreds and hundreds of feet into the air, I wouldn't even like to estimate how high it went.

Considering how powerful the output of the 2.5 mm core motor was I thought the 1.8 mm unit was a sure CATO. It didn't suprise me when milliseconds after lift-off its bulkhead gave way and propellant fragments soared 50 or more metres into the air.

Neither rocket was recovered, the CATOed motor was assumed to have landed near the launch tube, but a quick search did not locate it. The good motor probably ended up in the ocean.

Near to 3 mm is definately about 'right' using the 1/3 rds rule of thumb for rocket nozzles. A few more tests should prove this motor to be reliable enough to attempt payloads. It should have great lifting power.


title type size
2.5 mm Test Video video/x-msvideo 385.284 kbytes
1.8 mm Test Video video/x-msvideo 439.460 kbytes
2.5 mm Pre-Test Picture image/jpeg 61.221 kbytes
1.8 mm Pre-Test Picture image/jpeg 79.417 kbytes