I have been working on fiberglass lately so thought I would go ahead and fit the cowling. Rather than mount the propeller at this time I decided to make a spacer to position the prop spinner where it will be when the Hartzell is finally installed.
I began by taking a measurement from the face of the backplate to the machined flat surface on the back of the prop hub that will meet the crankshaft flange. This measurement was 2 inches. I then proceeded to fabricate a spacer assembly that would position the spinner assembly exactly 2 inches in front of the flywheel surface that will mate with the prop hub.
First, I cut a piece of particle board and bolted it to the backplate. Then the exact center of the backplate was determined and marked on the particle board. Next, I located four of the propeller mounting bolt holes in relation to the center of the backplate. These measurements were checked and rechecked to be sure everything was centered. Using some washers as shims and some 1/2" copper pipe cut as spacers I installed the spinner/backplate assembly exactly 2 inches from the flywheel face.
I took measurements around the spinner to be sure everything is true and plumb. I installed the screws and nylon washers in the fiberglass spinner temporarily. I should now be ready to install the cowl hinges and begin fitting the two piece cowl.
