Aerospace Engineering Portfolio
Cassandra Kapral
Rocket Design & Manufacturing
I'm a fourth-year Aerospace Engineering student at the University of Virginia focused on rocket propulsion and mechanical fabrication within flight systems. My work spans CFD and OpenRocket simulation comparisons, a carbon fiber motor mount with UVA Rocketry, aerodynamics research analyzing boattail drag, a model rocket class project, and hands-on fabrication projects like a wind chime as a Fabrication Fellow. When I'm not in class, I'm probably climbing. I was president of the climbing club and now run the social side of things as social chair.
Challenge: Our team needed to manufacture a carbon fiber motor mount tube by hand-laying composite plies over a machined aluminum mandrel, requiring both precise mandrel tolerances and a reliable release process to remove the cured tube without damage.
Action: I designed the mandrel in CAD and machined it from stock aluminum on a lathe to the tolerances required for the tube's inner diameter. After researching layup techniques by reaching out to other collegiate rocketry teams, we built a layup schedule combining 6k, 3k, and unidirectional carbon fiber plies with epoxy resin, then applied peel ply and shrink tape to compact the plies and control resin content during cure. When the first cured tube could not be removed from the mandrel, we isolated the issue to the mandrel-composite interface, revised the mandrel prep to include a Mylar release layer, and designed and built a new stand to support the mandrel during layup. We validated this updated process on a scaled-down aluminum test mandrel before scaling back up to the full-size version.
Result: The scaled-down test released successfully, confirming the release method itself was sound, but scaling the same process to the full-size mandrel reproduced the original failure, isolating the problem to mandrel size or geometry rather than the release technique. Due to time and budget constraints, we paused further attempts for the semester; at IREC 2026, we gathered manufacturing insight from other teams' composite processes and are applying those learnings to a revised approach this semester.
Challenge: Rocket boattails reduce base drag, but the relationship between boattail angle and drag reduction isn't fully understood — past a certain point, increasing the angle can actually start increasing drag again. Our team needed to determine how boattail angle affects drag by comparing two geometries, 5° and 15°, testing the hypothesis that drag would decrease as boattail angle increased.
Action: I focused on the design and fabrication side of the project, creating the CAD models for both boattail geometries and 3D printing the physical test articles used in wind tunnel testing. I also led the CFD analysis, running theoretical simulations to compare drag and flow separation behavior between the two angles. In parallel, our team tested the printed models in a wind tunnel using Particle Image Velocimetry (PIV) to visualize flow separation and measure drag differences between the two boattail angles.
Result: Our CFD and PIV analyses both supported the original hypothesis, showing that flow separation and drag decreased as boattail angle increased. However, our wind tunnel results were inconsistent: one trial supported the hypothesis while a repeated trial contradicted it, introducing uncertainty likely tied to sting calibration errors and test article attachment effects. Weighing the higher reliability of CFD against the wind tunnel's variability, we concluded it's more likely than not that drag decreases as boattail angle increases, though the evidence wasn't strong enough to state this conclusively.
Designed a wind chime in SolidWorks, calculating aluminum tube lengths to produce specific musical notes based on external acoustic references. Fabricated each tube through bandsaw cutting, vertical milling to face the edges, and lathe turning and sanding to a polished finish, then machined an aluminum holder with CNC-milled counterbores and waterjet-cut a brass striker and wind sail, connecting all components with nylon string.