7 July, 2020
LIGHTWEIGHT WOODEN SPINNER
Completed project
When building my Expression, I felt inspired and wanted to build as much as possible in wood, including the spinner. So I designed a spinner built up of balsa rings and some plywood. Each balsa ring is made up of 3 pieces to keep the fiber orientation somewhat constant over the circumference. The cone is held onto the backplate with 2 small woodscrews.
The spinner has been finished by applying sanding sealer with talcum powder to fill the grain, lightly sanding between coats and finally spraying with clear varnish. I did not add any glass reinforcement. total mass for this 68.5mm diameter spinner is 15.5gram. For fun I looked for a commercially available lightweight F3A competition spinner. I found a 70mm diameter carbon/alu spinner that was advertized with a mass of approximately 17gram.
The pictures show the spinner after I modified it by opening the front to increase the airflow to the motor for cooling.
