« Archives on January 22, 2012

Prop and cowl.

4 hours.

Prior to any fun stuff with the prop, I clecoed on the forward top skin. I did put clecoes in from upside-down along the front in a couple of places, But I think I’m going to take them out, because as somebody on VAF wrote, you’re trying to match the cowl to the skin, not the firewall flange.

So, remember that fancy purple custom spinner on my prop?  Turns out there isn’t a really good way to mock that up, short of scoring a junk Hartzell C2YR or C2YK rear hub half.  Here’s why:

The stock spinner is  a flat disc that can be mounted to the prop flange with six bolts, at the end of 2 1/4″ spacers.   This one mounts to the back of the prop hub using a 7/8″ spacer between it and the hub, to get it clear of the hub itself.   No place to attach bolts for the prop flange.


Here it is again from the side.


Measured from the back of the prop flange, It’s a little under the 2 1/4″ spacer length called for in the factory setup.

So a command decision was made to just hang the prop on the engine and fit the cowl based on the real deal instead of the mockup. This is acceptable, lots of guys have done it to no ill effect, other than it being an obstacle in the shop. However, with the blades set to vertical, it’s not in the way all that much. Initially I was going to see if David could help me hang the prop, but then I remembered, hey… I have an engine hoist. The installation guide in the prop manual recommends using a sling to position the prop anyway, so the hoist got yet another use.

I wrapped some blue masking tape around the blade roots to protect them from the straps, enhancing the plastic wrapping the prop shop put on the blades when I had it resealed a few months ago.   This gave me a pretty decent setup to get the prop hub flange lined up to the crankshaft flange.


This is where it got interesting.    The actual installation has you putting six studs in the prop flange, torquing them, then installing the prop to those via castle nuts with spring pins through them.   I don’t have that option.  You can see from the top pic that my prop came with the studs, castle nuts, and spring pins installed already, so the process became this:

Get the prop lined up as nicely as possible
Get all the studs started
Keep hand-turning each one a couple of turns until after an eon, the prop seats on the crankshaft flange.

This took a while, and they’re not torqued down at all. The whole point of this is to fit the cowl.


The top half of the pepto-pink cowl came down from the rafters to be sat atop the engine (from which I had previously removed the baffles in their current state), and I have to tell you, the pink/metallic purple combination is striking and eye-catching, in the worst way possible.

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