Aeroplane Powerplant Installation and Propellers
Engine installation
Engine mounts and isolators carry thrust and torque; dynafocal mounts align the mount legs with the engine's centre of gravity. The firewall and firewall shutoff valve, baffles and cowl flaps control cooling and fire containment. Exhaust systems are a carbon-monoxide source: cracked mufflers, slip joints and heat-exchanger walls must be inspected for cracks and soot trails. Engine controls need full-range travel checks and correct rigging.
Propellers
Fixed-pitch propellers are set by the manufacturer. Constant-speed propellers use a governor that ports oil pressure against springs and counterweights to change blade angle; loss of governor oil pressure drives the blades to fine pitch and overspeed. Feathering and reversing are separate functions with their own checks. Maintenance covers blade damage limits (nicks, gouges, corrosion), dressing, tracking, balance, hub inspection and NDT, and spinner condition.
Worked example
A constant-speed propeller overspeeds on takeoff. The governor is not driving blade angle up. Check governor oil supply and linkage first, then the governor itself, then the propeller. Do not adjust the governor before confirming that oil pressure is actually reaching it.
Traps
Treating a prop strike as cosmetic: the engine maker's inspection, including crank runout and possible tear-down, is mandatory. Ignoring exhaust cracks that leak CO into the cabin; using lubricated torque values on dry threads; mixing blade station limits.