So, I'm not sure how it'll work, but I'm making a baffle to direct air to the front of the motor, which is sitting behind a solid phenolic motor mount. In theory the ram air into the scoop will be directed to the front of the motor, where it doesn't really have much room to go anywhere but through the motor. If that works, then my motor will stay cool.
If it doesn't, then I'll stop trying to be too clever and I'll just look at what a lot of other people are doing, and do that.
It's of composite construction so it's cool. And it's made from a bunch of different stuff, so with luck it'll be light and strong. There's a 1/32" balsa core, with two layers of 1/4 oz fiberglass cloth on the inside and outside. I made no attempt to epoxy-proof the wood, so it'll probably soak up more than not (I could have used Bob Hunt's trick of spraying lacquer on it, but frankly -- I'm lazy). I'm hoping I get something light and stiff -- and it doesn't need much strength in the first place, so strength wise I'm already in overkill-land.
The dry ingredients going in weighed 1.4g, I mixed up 3g of resin and had 2g of resin left over (that's why I tared the scale with my brush and mixing stick included -- I wanted to get the weight of stuff stuck to them so I knew how much resin I used). So raw out of the mold (less any extraneous bits of waxed paper or plug stuck to it -- see below) it should weigh 2.4g, and then I'll trim it.
I didn't have any fancier material on hand, so I used waxed paper as a release agent. I've got my fingers crossed that this thing will pull, because I had epoxy weeping out of the paper as I wrapped it. So there may be a mess involved when it's cured. As long as it separates from the plug without breaking I'll be reasonably happy -- I'm going for usable, not a show-winning finish. If worse comes to worst I'll cut the plug out from the part, but that will be tedious.