John H wrote:

How large should the gap between the prop spinner and the cowling be on a IVP?

John,
I’d recommend a minimum of 3/8”; ½” is better. The reason is that the lower cowling on the IV-P must be lowered straight down about 8” to clear the prop spinner for removal. This is a very tight fit/difficult because the forward opening for the nose gear/gear doors needs to be as far back as possible for stiffness and operating reasons. This causes a difficult “geometry” problem in removing/installing the lower cowl…which you will do MANY times over the lifetime of the airplane. The result is that the front edge of the cowling that fits immediately behind the spinner gets scratched and beat up easily. With less than the above gap, you’ll have difficulty even removing the lower cowling. This is one area (like the elevator counterweight clearance on the horizontal stabilizer) where a close fit is not helpful, and actually creates a problem.

Hope this helps.

BOB