Saw it in a nice display at a gun show. We thought we could tell what the cowl flaps were, but we didn't know why they'd be adjusted or what they did.
Or if there's a better subreddit to ask in, that'd be good too.
Thanks!
Opening cowl flaps increases the airflow through the cowl, and this across the cylinders.
Cowl flaps are a cooling mechanism for propeller craft. They're opened during high-power/low-speed operations such as takeoff to maximize cooling and closed during flight to minimize drag.
/r/aviation is probably a better place to ask. While this control panel is specific to the B-17, cowl-flaps themselves aren't.