I'm in the process of installing some new avionics in a PA24-180, which includes an OAT probe. Therefore, I'd like to remove the existing mechanical OAT probe that goes through my one-piece windshield. Question: any ideas on how to plug the hole in the windshield, after the probe is removed? Obviously, something that will be aerodynamic, and NOT collect ice would be great.

Personally, I like the old fashioned OAT probe because it does collect ice. All the better to monitor the accumulation.

The best way is to replace the windscreen. Short of that, a countersunk machine screw, a tinnerman washer, a flat washer, a fiberlock nut and some RTV is about the best you can hope for. As for what I prefer. I have the probe, and as Kristin said it doubles as an ice detector. The small radius stuff on the plane will pick up ice first. In this case, the probe is about the smallest radius of anything on the plane including antennas, wings and tail leading edges. If painted black, it becomes immediately obvious when you pick up the first trace of ice.

Zach