Propeller, oil and engine cooling

Propellers

A propeller is a rotating wing that produces thrust. The blade is twisted so that each part of it meets the air at an efficient angle, since the tips travel much faster than the parts near the hub.

• Fixed-pitch: the blade angle can't change. Simple and cheap, used on most trainers. A "climb" prop is better for takeoff, a "cruise" prop for speed.
• Constant-speed: a governor changes the blade angle to hold the RPM you select with the propeller control, and you set power with the throttle and the manifold pressure gauge. This is part of the complex airplane endorsement later.

Oil

Engine oil does more than lubricate. It lubricates moving parts, cools the engine internally, seals the gap between pistons and cylinder walls, cleans by carrying away contaminants to the filter, and protects against corrosion. Always check the level before flight and carry the POH-specified type.

Cooling

Air enters the cowling, flows around the cylinder fins and leaves out the bottom. Cooling is weakest at high power and low airspeed, like a long climb on a hot day.

If temperatures run high: enrich the mixture, reduce power, increase airspeed (lower the nose), and open the cowl flaps if the airplane has them. A rising oil temperature with falling oil pressure is a serious warning sign; land as soon as possible.