5 hours.
Yesterday and today. I’ve been dreading this, mostly because the baffles are, uh, baffling. But with the cowl halves fit, it was time to seriously tuck into these things. Friday, I got a present from American Propeller, my new PCU5000x. I think they put the wrong spring on it, because the spring returns the control lever to the low-rpm position, but that’s no biggie, they can send me a new one. Either that or I pooched the order, which would suck, but it’s not a showstopper, I’ll just have to run the cable up from the bottom.
It’s a lot less bulky than the old McCauley that was on there originally, although I might have to reclock the bracket to clear the cowl. This is done by drilling a couple of offset holes in the bracket.
Yesterday, I farted around with the baffles for a while, putting them on in preparation for cutting the front ones to the cowl. I figured I’d be fancy with it this time and make some cardboard templates to get the shape right. This didn’t work out all that well. My plan to set it up like Bill Wightman’s installation didn’t work at all, because I couldn’t for the life of me transfer the shape of the governor pad onto the cardboard with any degree of satisfaction.
It seems simple enough, but it’s not, and I couldn’t quite make it work.
What I wound up doing was using the IO-540 baffles from the RV10 kit I’d ordered a while back. For some reason, this option dropped almost right into place. I had to modify the right side baffle to match the angle of the inlet ramp, but that worked out pretty well, once I actually figured out a good way to measure and cut it. The left front worked out fine, since the pre-cut hole was actually designed for a governor the size of the PCU5000X.
Today’s efforts consisted mostly of putting the bottom cowl on and taking it off again. A lot. I trimmed the front side baffles to clear the cowl, then worked on getting the proper shape for the right side.
This is the left front trimmed back enough to clear the cowl and nest in the spot just outboard of the cowl inlet.
Cutting the shapes was actually easier than I thought it would be. There’s a lot of extra metal on the front inlet ramps, maybe these things are designed to work with a variety of configurations, but the basic deal is that you have to trim everything so it tapers down to the rough opening of the cowl inlet. It takes several iterations.
Once you have the basic trimming done, the front inlet ramp comes off and you have to bend it along a line that starts at the point where the cowl inlet edge is tangent to the ramp surface and ends up in the corner where the front side baffle and inlet ramp connect. The bend brings the front ramp roughly into line with the inlet.
Like so. There’s still more trimming to be done, because the way this works is that a strip of baffle seal material goes around the pink bit and seals against the ramp and sides. On the right hand side of frame is the 540 front baffle. I’m not promising this is going to work, but it seems to fit OK., and if it doesn’t, I can use it as a template to cut on one of the spare 360 baffles I ordered from Van’s just in case.
Also a conical gusset goes in the corner where my fingers are, one that more or less matches the shape of the inlet. This does two things, it gives a better seal under pressure and stiffens the structure where the air comes in.
After that’s all done comes the fun part: Trimming the upper edges all around to match the contours of the top cowl.
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