upper cowl vent?

[Darick]

I was looking at the 2019 AirVenture pictures on the factory web site and noticed two round vents (at least they looked like vents) on the red B model upper cowl. Are they actually vents?

[Rynoth]

This would be on the Aerovee Turbo demonstrator I believe: https://www.sonexaircraft.com/wp-conten ... m_2844.jpg

The vents aren't required (as far as I know) but they were doing testing on different ways to help the Turbo cool down post-shutdown. I installed the vents on my own plane. Theirs are 4" wide circle vents, I installed 3" ones. I don't think they flow very much air in-flight (if they did I'd expect my windscreen to be dirty from the oil/coolant leaks I've been tracking down), it's mostly just for helping hot cowling air exit the cowling and help keep the turbo bearings cool (along with post-shutdown liquid cooling on the turbo.) Those vents are mentioned in this article: https://www.sonexaircraft.com/aeroveetu ... te_020618/

The article itself stated that the vents alone were minimally effective in keeping the turbo core temps down post-shutdown.

[GraemeSmith]

The builder of my Sonex put a small scoop on top of the cowl to direct air down onto the voltage regulator heat sink.

[Darick]

I like to open the oil fill door on top of my cowl after a flight to reduce the temperature under the cowl. It is really surprising to feel how hot the cowl becomes. I was hoping the vents would have open/close positions but that doesn't appear to be the case.