Gary, I opened up the bottom of the cowl for cooling and glow plug access. I had forgotten to install my remote glow adapter, and realized this when I got to the field. I was going to see how it ran without the bottom opened up, but ended up cutting it out in the field to access the glow plug. I opened up the two molded in slots in the front of the cowling during assembly, and just enough of the lower corner to clear the muffler which is very close to the lower left corner of the fuse front.

I've run this thing for several minutes doing "high speed" flybys without any overheating problems. The .52 runs very well in all flying conditions on this Cub from full speed to putting at just above idle. I first tried running a 12/6 APC prop, but found the motor likes an 11/7 Zinger on this plane as it doesn't have to work so hard. I want to try a 12/4 or 12/5 on it for a more scale look with lower load. The .52 is more than enough motor which provides quite a bit more than a scale top end speed.