Definition
A starting system in which an electric motor, powered by the aircraft battery, turns the engine crankshaft directly through a small pinion gear that engages a ring gear on the engine. When the pilot activates the starter switch, the motor spins the crankshaft fast enough for the ignition system to fire the spark plugs and the engine to start. Once the engine starts and exceeds the cranking speed, the pinion automatically disengages from the ring gear.
Plain English
An electric motor runs off the battery and spins the engine fast enough to start it. When the engine catches and speeds up, the motor disconnects on its own.
Context Anchor
Seen in aircraft starting-system descriptions and during engine-start procedures for piston-engine airplanes.
Derivation
Direct-cranking means the motor turns the crankshaft directly, with no inertia flywheel or wind-up stage in between like older starter designs used. Earlier aircraft used inertia starters that had to be spun up first; direct-cranking simply spins the engine the moment you press the switch.
Why Pilots Care
Delivers reliable, repeatable starts without manual cranking or separate inertia mechanisms.
Analogy
It works much like the starter in a car: an electric motor briefly turns the engine fast enough for it to begin running on its own.
Intuition Check
Do not read “direct-cranking” as hand-cranking the propeller. Here it means an electric starter motor directly turns the engine for starting.
Example Sentence 1
Most modern piston singles use a direct-cranking electric starter system, so starting the engine is just a matter of turning the key with the mixture and throttle set correctly.
Example Sentence 2
During a cold-weather start, the direct-cranking electric starter system maintained steady cranking speed until the engine fired.