[grover]

is it possible to fit the cowl without the prop/spinner/spacer etc? plans make reference to upper cowl position with respect to back side of spinner. can it be done by alternate means (no spinner, etc, acquired yet)?

 

[Danny King]

Fitting the Cowling

No! It is important that you have the engine in place or, at least a core case and crankshaft, so you can mount the rear spinner to the crankshaft with a spacer as per plans, cut and fit the cowling at the firewall end.

Jay Pratt built a cowling jig out of a spinner aft bulkhead. He used PVC spacers to simulate the propeller hub, and a plywood spacer anchored to the back of the spinner bulkhead to set the proper distance between the rear of the spinner bulkhead and the front of the cowling. There are two holes in it on each side, so you can drill a #3 size hole in the lip of the lower cowl to bolt the lower cowling to the bulkhead in the proper position. This is important because you must remove and reinstall the lower cowling over and over again as you carefully trim the firewall end. It is imperative that the cowling returns to exactly the same position at the spinner after each trim until both sides and the bottom of the cowling fits correctly to the fuselage.

 

[cvondoymi]

fitting cowling

Check out this from Vans. Go to simmulating the propeller.
http://www.vansaircraft.com/public/confaq.htm
Carl

 

[Rick6a]

The FAQ instructions on Van's website seem to be at variance with the following text Section 12 page 12-2 of the builders manual. It states: "If you are installing a constant-speed propeller, it is best if the prop is installed, because, in this case, the spinner back plate mounts to the prop."

The text does go on to say "If the prop is not available, a spacer 2 1/4" thick....may be used to simulate it."

Given that many people experience and report gap problems when using spacers to simulate the distance, I tend to agree that generally, it is best to first install the (constant-speed) propeller....if possible.