CS Prop Spinner/Cowl Distance

6A. O-360, CS Prop, Pink Cowl

I am trying to set the distance between my flywheel and back spinner plate do I can fit my cowl. Scouring the web, I have seen suggestions to wait to fit the cowl until I have the prop installed and others saying to do it without the prop installed. My question related to fitting the cowl without the prop installed.

I have found documents that say to place 2 1/4" spacers between the flywheel and back spinner plate to simulate the compact hub of the CS prop. There is then suppose to be at least a 1/8" gap between the back spinner plate and the cowl. It seems like I could just make 2 1/8" spacers and flush fit the cowl to the back spinner plate. Comments?

Just a note. Since the back spinner plate has a 5/8" flange, using a 2 1/4" spacer will result in a distance between the flywheel and the back of the spinner of 1 5/8".

Also, is it correct that the pink cowl is epoxy so I can not use polyester fiberglass for any of the work on it?

Does all this sound right?

Thanks
Ross
N9PT rebuild

I can get some dimensions for you, but first . . .

1. it is best to know what prop you are starting with
2. What clearance do you want?
3. Do you have your spinner?

I had to do all this with my SJ cowl and composite prop. It was going to hit the air inlets at full pitch, so I took a lot of measurements.

PM me - or PM/email if you wish.

Dimensions - add and subract

You can add a wood disk that the cowling can contact if you size your temporary spacer correctly. You can also do this without the flywheel installed.

The trick is to get the plus and minus dimensions correct - this figure can help, but check and adjust the numbers for your set-up.

rmickey said:

I have found documents that say to place 2 1/4" spacers between the flywheel and back spinner plate to simulate the compact hub of the CS prop. There is then suppose to be at least a 1/8" gap between the back spinner plate and the cowl. It seems like I could just make 2 1/8" spacers and flush fit the cowl to the back spinner plate. Comments?

Click to expand...

I fit my cowl successfully without the prop hub (fixed pitch). I cut the spacers made from PVC pipe to the same 2 1/4" spacer dimensions, then put on the spinner bulkhead.



You are going to want more like a 1/4" gap between the aft spinner bulkhead and cowling. You need this space if you are using the hinge attach method in order to be able to pull the cowling forward enough to clear the hinge eyelets on the firewall.



I used a piece of plywood as a spacer once I had the rough cuts on the cowling done.



The plywood spacer got some 1" holes cut to allow it to fit over the PVC pipe sections.



Lots more photos and commentary here.

I used West System epoxy for all of the filling and other build ups for hinge pin covers, etc.

Thanks so much. Great picture. The prop is a Hartzell CS w/compact hub and I do have my spinner.

I just measured the distance from the prop mounting flange to the edge of the fitted spinner. It is 1.64-1.65". The spinner cone stands proud of the backer flange by .10 " , so you might tap yours in position at room temperature and check where it settles out. I sanded the inside of the cone just to knock off nibs. Fiberglass expands more than aluminum so temp is a factor.

If you use spacers, then be sure the disc is centered on the crank!!

I drilled the holes in a disc made of 1/4 luan with a hole in the center that matched my crank. That way ensured the bolt holes matched the crank perfectly. With several bolts in place, (tight to the holes) it could only have been centered. This was the disc used to begin fitting the ends of the cowl pieces together. Holes in the disc with clecos to the cowl ensured that the desired split line was achieved. (using the DanH method of cowl fitting).

The disc also served as the datum for firewall fitting.

Enjoy, this was easier than I had thought it would be and satisfying to have done.

BillL said:

I just measured the distance from the prop mounting flange to the edge of the fitted spinner. It is 1.64-1.65".

Click to expand...

Is this the distance with or without the flywheel?

Ross