Over the past week, I constructed and tested two rocket motors using a 65/35 KNSU composition with 0.375" core diameter. The nozzles utilized hybrid concrete/PVC end-caps, while new firewire initiators provided reliable ignition capability.

First Test

The initial test proved successful, delivering a thrust profile with:

  • Total impulse: 76.2 N·s
  • Specific impulse: approximately 0.75-0.8 (using theoretical density calculations)

This performance demonstrated rapid ignition and accelerated burn characteristics.

Second Test

The second motor failed to ignite despite using four separate initiators. Upon disassembly, examination revealed an intact grain structure with no voids and a charred core. I attribute the ignition failure to insufficient drying of WD-40, which likely created an insulative barrier between the initiator and fuel core.

Looking Ahead

Recent supplier changes have yielded improved fuel performance. I plan to prioritize RTEM system development through summer rather than pursuing full motor optimization.

Additional goals include:

  • Increased model rocket range visits
  • Pursuit of a Junior-L1 certification by season's end