Tom
This method worked very well for me. I copied and pasted from an old post and the pictures didn't make it. Do a search on cowl fitting and you'll find the post from me. I couldn't figure out how to post a link to that thread otherwise I would have done it that way. By the way This method worked perfectly for me twice now without using the prop.
Good luck
Jon
I just finished fitting the cowl to one of the 8's I'm building and thought I'd pass on this tip.
I have the prop (Hartz. BA) and engine (O-360A1A), and I want to fit them to both airplanes. In the interest of speed I wanted to try the spacer method of prop simulation. In the past I've always hung the prop and did the cowl fit with the prop in place. I figured the spacer method should work.
So I went to the local hardware store and bought some 1/2" fine thread bolts, 3 inches long and brought them home.
I then cut some spacers 2 1/4" long from some 3/4" Sched. 40 pvc pipe on a power miter saw so that they would be square cut.
Ready to mount the bulkhead, oops the holes in the bulkhead are 5/8's" bolts are 1/2". Back to the hardware store to look for some bushings.
Ah! Victory! For once the hardware store has not only a 5/8's X 1/2" bushing, but 6 of them!
So here's how it worked. Put 2 washers on each bolt, then a bushing, tape the bushing in place against the washers. Put the bulkhead on the bolt/bushing combo's, put spacer's over bolts.
Put assembly on crankshaft over starter ring gear. Tighten up bolts, making sure bushings haven't slipped down on the bolts.
It sure looked straight and square to me!
Next up, top cowl positioning. I used a piece of 3/16' plywood that was laying around from a kitchen project and positioned it up against the aft flange of the spinner bulkhead. Then I positioned the top cowl tight up against the plywood spacer, marked the cowl from the reference lines and trimmed it. Gee I hope this spacer thing works.
Fast fwd. a month. Cowl finished, baffles finished, carb air box finished, time to do the spinner. I figured I could do that on the bench, but the twisting of the prop blades to check clearances would be difficult. So lets hang that prop and see if that spacer method worked.
Put the bulkhead assembly on the rear of the prop, hang the prop, say a prayer and then put the cowl on.
Guess what! That 3/16's plywood just slips between the cowl and the bulkhead. Ah! Victory again!
The victory is short lived though, as I will now be removing the engine from the first plane and installing it on # 2, starting the whole process over. I will definitely use the spacer method from now on.
Here's some pix of the spacer method.
http://www.vansairforce.com/community/showthread.php?t=22903
__________________
Jon
Habitual Offender
RV4, RV4, RV6A, RV8, RV8, RV8
