Abstract :
AUTOMATIC temperature control for aircraft long has been neglected, and it is only during the war that adequate attention has been given to this important subject. The increased duties imposed upon flight personnel by the requirements of modern military aircraft, together with the necessity for reducing air drag to the minimum consistent with required cooling, have prompted aircraft designers to give consideration to automatic operation of cowl flaps, oil and coolant flaps, and intercooler doors. Automatic flap operation can be appreciated fully when it is considered that engine cowl flaps fully opened might represent an air drag as high as 40 miles per hour on a 400-mile-per-hour airplane.