Photos: Julian Rice
Rocket Diameter / Length: 54mm / 41.5"
Max Speed: Mach 3.6 / 2700mph
Altitude: 21,000ft.
Acceleration: >100G
SRM Class: L2100
Recovery Status: Nominally Recovered
Launch Date: April 6, 2024
Special Thanks: Julien Denat of IPSA Paris
First conceived in January 2024, the purpose of Deja Vu from the outset was to expand on Julien Denat's architecture of his rocket "Gas Gas Gas." The rocket was to feature a commercial RCS Rocket Motor Components EMK (experimental motor kit), commercial Ammonium Perchlorate Composite Propellant in a custom geometry, an integrated motor forward closure-nose cone coupler assembly, and an extremely compact and lightweight structural avionics bay package. This simplification throughout the design of the rocket was made in order to reduce volume, mass, manufacturing costs, and time spent on build, while prioritizing high-thrust, acceleration, and speed. This is likely the most well-known of my personal projects, as it demonstrated very high-speed flight, with simple design and construction, in a way very uncommon in the amateur rocketry community.
From top to bottom, the rocket was designed to be simple, lightweight, cost-effective, and optimized not to the final degree, but rather to a degree that balanced integration and design ease, with raw performance. The nose tip, forward closure, and an adapter piece from a G10 laminate avionics sled to the nose tip, were all machined out of 6061-T6 aluminum. The avionics bay featured a single GPS tracket and barometric altimeter/recovery deployment computer, responsible for transmitting location, as well as ensuring safe recovery of the rocket. The parachute and shock cord were packed inside of the nose cone and forward closure/coupler piece, an approach more volume-efficient than most conventional designs. This coupler was responsible for sealing combustion gases at the top of the motor, anchoring the recovery system, and providing a sturdy nose cone coupling point. The propellant was designed in a stepped-BATES geometry, to strike a balance of manufacturing ease and a relatively flat thrust curve. The fins were composed of 3D-printed AlSi10Mg, and designed by Julien Denat for use on his Gas Gas Gas project, being repurposed later on for this project.
All CAD was done in Autodesk Fusion 360, and the rocket design softwares OpenMotor and Openrocket were used.
Launch operations and build for this rocket are some of the smoothest and easiest of my time in amateur rocketry. Launch occurred at 10:07 AM on April 6, on a cool Mojave morning. Recovery occurred with a nominal drogue and main parachute deployment. Upon recovery, a beautiful "Mach rash" was found on the rocket, with paint stripped along the body of the rocket. If not for the single-use nature of the motor, all components of the rocket would be ready for a reflight with minimal refurbishment.