cowl flaps, please help!

Best explanation I've ever seen.
Everything should have a page like this, life would be so nice!

http://stoenworks.com/Tutorials/Cowl%20Flaps%20&%20Engine%20C.html

Thanks! I understand it now

Cowl flaps are basically control valves or doors that regulate how much air flows through the engine compartment for cooling purposes. Proper air flow around the engine is crucial to engine life. Too much air flow especially at altitude and cruise power can be damaging because there can be too much of a temperature gradient across the cylinders and heads, this is called shock cooling and can literally crack the engine block and cylinders not unlike pouring cold water on a hot glass. The cowl flaps are used to prevent that by limiting the flow of cold air over the engine.

This is how me and cowl flaps work!
Take off - open
Cruise - 1/2
Descent - Closed
Final approach - open in preperation for Go Around.
This makes things simple!