If you want to take it a notch further, check out Oregon Scale Aviation's ThermaCowl.
Here's a description and link at the end:
Where Scale Realism Meets Unprecedented Functionality
ThermaCowl Ultra enables the scale or sport aviation enthusiast to automatically control the opening and closing of cowl or cooling flaps in a scale-like manner. As the engine compartment temperature increases, the cowl flaps open wider to allow further cooling. Because the cowl flap position is controlled by temperature, ThermaCowl Ultra aids in maintaining a constant engine compartment temperature. This provides quicker warm-ups, and fewer lean run flame-outs. This control feature was found on many of the WWII era aircraft, and you will find ThermaCowl Ultra an excellent addition to your scale project to add that final touch of realism.
ThermaCowl Ultra adds the ability to optionally open the cowl flaps whenever the wing flaps (or any other channel you choose) are deployed. This feature allows you to verify correct operation while in the pits, and to demonstrate operational cowl flaps any time the radio system is on.
http://www.oregonscaleaviation.com/R...hermaCowl.html