After the relative success of PSP Hybrids' previous rocket, 'HAVOC,' plans for the next rocket, 'SPECTRE,' were drafted during the summer of 2023. I joined the group in August 2023 as a member of the airframe subteam, focusing on the aerodynamic components of the project, specifically the fins and nose cone. Over the course of my one-year tenure with the team, I advanced to the role of 'Aerodynamics Specialist,' where I was responsible for creating the CAD models for the components mentioned above.

PSP Hybrids is a rocket team that employs a hybrid combustion technique, using solid fuel propellant and liquid oxidizer. This approach is not based on any particular reason; rather, it represents the foundational concept of the team. The rockets developed by this team have been impressively large, and Hybrids' rockets, particularly the SPECTRE, have lived up to expectations. The SPECTRE is designed to reach a maximum altitude of 25,000 ft. With an outer diameter of 8", the rocket is expected to achieve supersonic velocities at its peak. Simulated launches have confirmed that it will successfully reach its target altitude.

When I joined PSP Hybrids, I chose to join the Airframe/Structures subteam, which is responsible for the entire shell of the rocket. At the time, SPECTRE was still in its early draft stages, so there was no substantial research into the rocket yet. While there was some prior experience from the previous rocket, HAVOC, it was decided that SPECTRE would be built from scratch. In the first few weeks as part of Hybrids, I focused on conducting a literature review. The component I chose to work on initially was the nose cone. After researching prior art, I determined that since this rocket would be subsonic for most of its flight, a 5:1 tangent Ogive-shaped nose cone would be ideal. This nose cone would be purchased from an external vendor instead of being manufactured in-house. During my research on nose cones, I also explored composites, particularly carbon fiber and carbon fiber reinforced polymers (CFRP). Although the team ultimately chose to stick with the fiberglass nose cone used in HAVOC, I gained valuable knowledge about CFRP, which is becoming increasingly used in rocketry. Based on my research, I created the CAD model for the nose cone and how it would integrate with the rest of the airframe. The CAD model for the nose cone is shown below.

Eventually, I took on a specialized role focusing on the aerodynamic components of the airframe, which included both the tail fins and the nose cone. Due to the lack of existing research on the fins, I applied the same process I used for the nose cone, researching design techniques for fins on a subsonic rocket. I delved into the materials for the fins and decided to use fiberglass, following the example set by HAVOC. The fins were designed with a trapezoidal shape. The more challenging aspect came with integrating the fins into the rocket’s airframe. During my time on the team, we explored various ideas. Initially, I designed a fin can, a large cylinder with fins attached to protrusions on the can. We considered two approaches for this design: an external fin can, which would be bolted flush with the airframe, and an internal fin can, which would fit concentrically inside the airframe with the protrusions fitting into orifices flush with the airframe. The primary drafts of both designs are shown below. However, both concepts were eventually discarded in favor of fin can rings. The fin can rings would consist of two rings, and the attachment slots (previously referred to as protrusions) would be bolted to these rings to create a rigid can-like structure. This design would resemble a can but would only serve as a frame. The fins would then be bolted into the attachment slots. The fin can ring structure would sit inside the main airframe, similar to the interior fin can design, but it would save significant space and mass. The CAD model I created for the fin can is also shown below.

First Fin Can Drawings

Fin Ring Structure CAD Model