This was the first fire of an Aerospike nozzle for my Senior Project in...(More)

This was the first fire of an Aerospike nozzle for my Senior Project in Aerospace Engineering from California Polytechnic State University in San Luis Obispo. The test bed hybrid uses gaseous oxygen, GOX, and a 2" dia Plexiglas tube as the solid fuel. The Oxygen is at 100psi. This test run was not choked, which was expected for the throat area is ~10 times greater than what the ideal area should be. The ideal gap between the spike and the compression cowl needed to be .003", yes, 3 thousands of an inch. However, if this were too small, this could produce a thermal choke well in front of the actual physical choke, which would reduce the performance of the rocket. I machined the compression cowl to have a gap of .053" instead. This would have allowed me to re-machine it smaller to maximize the thrust of the rocket. I planned to fire the test for only 10 seconds, however I got distracted and allowed it to fire for 20 seconds, 2-3 seconds shy of turning the two piece nozzle into 3 or more pieces, thats what all the sparks are at the end. This nozzle was machined out of 4140 Chrome-Molly. What took over 32 hours of CNC machining only took 20 seconds to destroy. Now you know why they call this rocket science.(Less)