For this year's Teknofest UAV, the LAG-4, we chose to construct the entire airframe from carbon fiber using a vacuum infusion technique. As this was our first attempt at vacuum infusion, the testing and development process took roughly a month. The result was a full carbon-fiber UAV body that is both highly durable and lightweight.
Preparing the mould
Once the design phase is complete, we produce the mold designs and 3D print them using PETG filament, chosen for its durability, print quality, and heat resistance. The printed molds are then sanded progressively, from 80-grit up to 2000-grit, to achieve a smooth finish. Filler is applied to the mold surface to seal any remaining imperfections.
Laying up the carbon
With the mold prepared, we cut our carbon fiber sheets (200 g/m²) and apply adhesive spray to help the layers bond more easily. Once dry, the layers are stacked with epoxy resin applied between each sheet. This layered carbon fiber is then carefully placed over the mold, ensuring full surface contact.
Bagging and curing
Finally, we construct a vacuum bag using dough tape and rolled bagging film, incorporating a spiral hose and vacuum inlet before sealing the assembly. The vacuum pump is then run until a stable vacuum is achieved, after which the part is left to cure for 24 hours.