Bill's RV-7 Project

I measured the circumferance of the spinner base: 41 inches. I marked the zero and 180 degree point to reference for the prop cutout. I could try and make a crude cutout template from cardboard. But I heard Hartrzell -- maker of my prop -- has a template for the Van's spinner in PDF format they'll email you. So I'll see if I can get that.

I had the #3 and #4 cylinder baffle assemblys all clecoed together. Naively, I thought I'd be able to just slide the assemblys right in. Not a chance. Not even close! So I took the #3 assembly apart and tried mounting it. The side piece fit fine but no-go on the aft piece.

I calmed down during the break and took another shot at it. This time I would take it one piece at a time and work systematically. I started with the #4 baffle aft inboard piece. Why did it not fit? After staring at it for awhile, I realized that the tab below was bumping against a big nut on the engine.

I screwed down the #2 and #4 side baffles. The baffles holes lined up perfectly with the engine holes.

And from the top. Notice how the aft bracket is pointing straight up. I'm going to have to do something about it. I don't want the baffles bulging aft in the center.

Back to the #3 baffle. I looked at the aft baffle and saw where it needed trimming, just below the engine mounting bolt hole.

I realized I needed to trim the corner of the wider tab, marked below in red Sharpie.

The baffle screws onto the engine on the outboard edge. The baffle hole was pre-drilled. Amazingly, once I got the baffle trimmed, the baffle and engine holes lined up perfectly.

April 20, 2007 - Spinner & Baffles Begin
I decided to start on the spinner and baffles today, since the cowl is on hold waiting for my Milspec Camlocs. I started off by bolting on the front spinner bulkhead. I had to use all three supplied washers per bolt to prevent the bolt from "bottoming" out.

I measured the circumferance of the spinner base: 41 inches. I marked the zero and 180 degree point to reference for the prop cutout. I could try and make a crude cutout template from cardboard. But I heard Hartrzell -- maker of my prop -- has a template for the Van's spinner in PDF format they'll email you. So I'll see if I can get that.

And now, the time has come to start work on the dreaded "baffles". The baffles are a critical for cooling the engine. Essentially, they are barriers which channel the air flow through the cylinder fins. Historically, the baffles have challenged builders because the instructions and drawings were poor and it was difficult just to figure out what was supposed to go where. But I have the latest baffle kit from Vans and supposedly the new kit makes installing the baffles things much easier. I sincerely hope so. I had already spent a week edge-smoothing all the baffle components, and doing what I could before engine mounting. First step was to mount the Aft Center Support and Forward Center brackets. Right away I ran into trouble -- the lightspeed thingamajig was right were the Aft bracket was supposed to go. I should be able to mount the Lightspeed in the middle like shown.

I had the #3 and #4 cylinder baffle assemblys all clecoed together. Naively, I thought I'd be able to just slide the assemblys right in. Not a chance. Not even close! So I took the #3 assembly apart and tried mounting it. The side piece fit fine but no-go on the aft piece.

So I tried the left side #4 assembly. Again the side piece fit fine.

But the aft piece didn't. I was rather dismayed at this point so I took a break. I checked my favorite builder's websites but none of them used the new baffle kit, and most of them had different engine flavors.

Per the instructions, I made this spacer for the #4 baffle.

I calmed down during the break and took another shot at it. This time I would take it one piece at a time and work systematically. I started with the #4 baffle aft inboard piece. Why did it not fit? After staring at it for awhile, I realized that the tab below was bumping against a big nut on the engine.

I trimmed it off and the baffle now fit nicely where it was supposed to. Except the there was a problem where it connected with the Aft Center Support Bracket. It wasn't the baffle. It was the bracket. The bracket face extended about 1/8 too much aft.

I screwed down the #2 and #4 side baffles. The baffles holes lined up perfectly with the engine holes.

Then I fit the aft outboard baffle. I was amazed -- and happy -- when it fit perfectly. Making some progress now.

Looking aft.

Looking from the elft side.

And from the top. Notice how the aft bracket is pointing straight up. I'm going to have to do something about it. I don't want the baffles bulging aft in the center.

See how the bracket extends too far aft?

Back to the #3 baffle. I looked at the aft baffle and saw where it needed trimming, just below the engine mounting bolt hole.

I ended up having to trim away quite a big in this area before I got it right.

It was an iterative process: trim and fit, trim and fit.


There was also an issue down below. The aluminum tube was in the way of the curved tabs.

I realized I needed to trim the corner of the wider tab, marked below in red Sharpie.

Still triming around the engine mount bolt hole.

The baffle screws onto the engine on the outboard edge. The baffle hole was pre-drilled. Amazingly, once I got the baffle trimmed, the baffle and engine holes lined up perfectly.

The baffle also screws to the engine near the engine mount bolt.

My curved tab trimming did the trick.

And the #1 and #3 baffles are mounted. I think I made pretty good progress on my first Baffle day.


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April 20, 2007 - Spinner & Baffles Begin