I spent a lot of time reading up on cowl installations and one thing I need to determine is how far the spinner sits from the fly wheel. This will allow me to use a mock up that will give me the forward most position of the cowling. There is a diagram that shows the dimension at 1.62” but I seem to come up with 1.64” when I calculate the thickness of all the parts. To get my measurements I bolted the spinner back onto the ring attached to the propeller. I made some spacers that will hold a piece of clear Lexan cut to the 13” diameter of the spinner back, at the exact place that cowl need to sit to give me a 3/16” gap between the cowl and the spinner back. The plans call for this gap to be 3/16” to ¼”.
I am not sure I want to trust this mock up, I have seen where many will just mount the propeller. If I mount the propeller I will have an accurate place to measure and get the cowl gap set, but the bad part is the cowl fitting is a very iterative process and it will come on a and off several times, the prop will be in the way for this. The other thing about the mock up is you can cleco the front of the cowl to it which is nice. Hmmm what to do, what to do! The clear Lexan is nice but a little flimsy to set my cowl spacing off of, I will cut a piece of MDF to stiffen up the mock up, that is if I can trust it. I might just fit the top cowl with the mock up but before cutting the aft side I will mount the prop to see how it works. If it goes well then the prop can come off and I will use the mock up for the rest of the cowl fitting. Sorry, thinking with the keyboard, stay tuned to see what I come up with.
