Issue link: https://www.e-digitaleditions.com/i/1520252
20 MAY/JUNE 2024 SPORT ROCKETRY Figure 8. Reinforcing the model with a layer of carbon fiber cloth. Optional rein- forcement step e monocopter employs helicopter spin for recovery. However, landing on a hard surface (like a paved road) can prove fatal, causing the model to break on landing. To help prevent this I recommend glass- ing the bottom surface with a layer of car- bon fiber or fiberglass. Figure 8 shows a reinforced design. I cut a strip of 6K car- bon fiber cloth from Soller Composites. I applied a coat of epoxy resin then used a food saver to vacuum bag it. Although this will increase the model's weight, it adds strength and gives additional protection upon landing. Using lower infill for the glassed version may be possible, but I have yet to explore this. Final assembly and checkout 1. Install the threaded rod. Drill the hole out for the threaded rod with the 11/64-inch bit. 2. Center the rod and fasten it with nuts. freely on the 3/8-inch diameter launch rod and does not bind as you slide it up and down. 4. Motor selection. Use D12-P (if you can find them) or D12, any delay. I have also used Estes E motors and Aero- Tech F24 motors. 5. Balancing. Insert a motor, and make sure the monocopter is reasonably balanced. en, use the nuts on the threaded rod to adjust the balance on the x-axis. It does not have to balance perfectly but should not have a signifi- cant wobble. Launch set-up You will need to fashion a launch rod 3/8 inches in diameter and 3 inches in length to launch the monocopter (Figure 10). e monocopter should rest two inches from the end of the rod. I use a fiberglass rod from McMaster-Car, but any sturdy ma- terial will do, including aluminum, fiber- glass, or wood. You will also need to figure out how to support the launch rod. I rec- ommend a drill chuck secured on a stand. Insert the launch rod one inch into the chuck to expose two inches. Place a nylon washer or spacer between the chuck and the model. Figure 11 shows the launch rod setup. It should be sturdy and short enough to not bend as the monocopter accelerates. 1. Insert the motor and secure the motor place with masking or painter's tape. 2. Secure the 3/8" diameter launch rod post in a drill chuck or other fixture. 3. Place the monocopter on the launch rod post so it rests two inches from the top end. Make sure it spins freely and does not bind as you slide it on the rod. Ensure you insert the "down" side Place two nuts next to the motor mount. Place two on each end of the threaded rod. One nut on each side will be a lock nut (Figure 9). 3. Double-check the launch rod in the motor mount rod hole and drill as necessary with the 13/32-inch drill bit. You may need to sand or file as well. Ensure that the monocopter spins Figure 7. Apply edge fillets, top and bottom.