Definition
The thick, rounded inner sections of a propeller blade, located close to the hub, where each blade attaches to the propeller assembly. Blade shanks are structural rather than aerodynamic — they carry the loads from the spinning blade into the hub but produce little useful thrust because of their round, untwisted shape.
Plain English
The chunky base of each propeller blade, right next to the hub. It's the part that holds the blade onto the propeller, not the part that does the work of pulling the airplane through the air.
Context Anchor
Seen in propeller blade-angle control discussions, especially when explaining how a propeller blade changes angle instead of staying fixed in one position.
Derivation
Shank' comes from Old English 'scanca,' meaning the leg between knee and ankle. In tools and mechanical parts, it refers to the straight, plain section between a working end and an attachment point — like the shank of a screwdriver or a key. On a propeller blade, the shank is the plain structural section between the hub and the airfoil portion that does the actual work.
Why Pilots Care
Wear, corrosion, or binding at the blade shanks can prevent proper pitch changes, leading to loss of constant-speed control or inability to feather the propeller.
Intuition Check
Do not picture the entire propeller blade. The blade shank is specifically the thick inner/root portion of each blade where it is held at the center of the propeller.
Example Sentence 1
During preflight, the pilot inspected the blade shanks for cracks or corrosion where each blade enters the hub.
Example Sentence 2
When the propeller governor called for a higher pitch, the mechanism rotated the blade shanks inside the hub.