Nuka Cola

31,000’ AGL. Mach 3.2. Successful recovery.

Nuka Cola was our first fully integrated flight vehicle. Launched at BALLS 31 in 2023, it flew on an experimental Fatboy motor and reached an altitude of 31,000’ AGL and speed of Mach 3.2.

Details

We set out on the design of Nuka Cola with a couple specific goals in mind:

Break Mach 3.
Fly above 30,000’ AGL.
Test moderate altitude recovery.
Verify construction techniques.

Through this project, all four of these goals were met. Nuka Cola serves as the foundation for future flights, from which construction techniques and rocket architecture will be derived. In the following sections, each system of the rocket is discussed.

Propulsion

The power plant, which was contained with a 3”x41” motor casing, contained 10.4 lbs of propellant and yielded a net total impulse of 9370 N-s to the flight vehicle. It averaged at 2640 N of thrust, peaking at 3750 N. This motor was a demonstration of our in-development bismuth propellant, which had just begun demonstrating high delivered density impulse metrics. A video of the static test fire is shown below:

Aero Structures

Nuka Cola’s fins and nose cone were designed with manufacturability as the leading priority, while still retaining good performance characteristics. The nose cone was constructed through use of a standard wet layup. Five layers of biaxial carbon fiber sleeve were first laid onto the nose cone mold, which was followed by one surface layer of biaxial fiberglass sleeve. The carbon fiber provided the structural integrity of the component while the fiberglass layer enhanced the post-processing characteristics of the cone. Pictures showing this process are provided below:

Nose cone mold prepared.

Wet layup complete.

Completed assembly.

The main flight events were controlled by a redundant pair of PerfectFlite StratologgerCFs. These are the minimalistic approach to avionics—they only record altitude, from which velocity and possibly acceleration can be derived. Since this was not an extremely high altitude flight, these barometric-type altimeters worked well for the job and were already on-hand. The tracking was provided by a Featherweight GPS, which led us directly to the landing coordinates of the rocket. The joint separation was actuated by redundant black powder charges which were heavily ground tested to ensure ballistic re-entry was not a possibility.

Nuka Cola used a traditional head-end dual deploy system for recovery. Between the motor and the avionics bay sat the main parachute—the drogue parachute resided in the nose cone of the rocket. See below a picture the recovery system sprawled out post-flight: