The fincan was the largest composite part on Felicette. It was attached to the bottom coupler of the propellant tanks by radial screws and covered the intertank and Calico engine. The Felicette fincan kept the rocket roll-stabilized during flight by utilizing canted fins, which induce a high roll rate to maintain the vehicle above the pitch and yaw natural frequencies. This helps prevent roll lock-in and catastrophic yaw, which Darcy II launch attempt 1 suffered. Given there are no signs that Felicette suffered catastrophic yaw, as well as the fact that the team was able to observe Felicette spin, roll stabilization seems to have worked as intended. The fincan was a result of a very long manufacturing process. The first step was the initial wet layup of the fincan, followed by post-processing and post-machining for the various holes in the fincan. The custom-made carbon fiber fins were chamfered and precisely installed, followed by a final tip-to-tip layup for added strength. The fincan’s roll-stabilized nature helped Felicette recover after the premature reco deployment and was likely a major contributor to Felicette’s final apogee. Notably, the fincan proved to be incredibly sturdy, surviving mostly intact after a ballistic descent.
