I designed and built this rocket with the goal of breaking the high school record of 45kft. I used a different approach than what been tried before, using an N-Class moonburner(offset core) propellant geometry to have a longer burn, allowing the rocket to punch through most of the thicker atmosphere at lower speed, losing less energy to drag. 

Structurally, the rocket was very conventional, using a bonded carbon fiber fin can and 9 ply Kevlar/Fiberglass nosecone, which in hindsight were way overbuilt for the flight profile. A machined aluminum coupler slid into the motor casing, and the nosecone bolted directly to this coupler. That same bolted joint also secured the avionics bay, sandwiching it between the nosecone and coupler, which significantly improved the integration process.

I flew the rocket with a GC10nx geiger counter board which I modified with a custom BMP390 barometer breakout board and wrote custom C++ firmware for to enable data logging of CPM with respect to altitude.

I flew the rocket at Friends of Amateur Rocketry to 40,539' at Mach 2.8, undershooting my simulations by around ~10kft, due to coning caused by aerodynamic and mass asymmetries on the rocket. Importantly, I recovered the geiger counter data, and it matched the trend I expected, but it hit the maximum CPM my board could measure