Definition
A secondary connecting rod used in a radial aircraft engine that attaches to a knuckle pin on the master connecting rod rather than directly to the crankshaft. In a radial engine, only one piston's rod (the master rod) connects directly to the crankshaft journal; the remaining pistons drive articulated rods that pivot on pins set around the master rod's flange.
Plain English
In a radial engine, only one piston's rod is connected straight to the crankshaft. The other pistons use shorter rods that hinge off that main rod instead. Those hinged rods are called articulated connecting rods.
Context Anchor
Seen in radial engine construction, engine diagrams, and maintenance discussions about how piston motion is carried to the crankshaft.
Derivation
From the Latin articulatus, meaning 'jointed' or 'divided into joints.' An articulated rod is one that joins onto another part through a pivoting joint — in this case, the knuckle pin on the master rod — rather than connecting directly to the crankshaft.
Why Pilots Care
Articulated rods are the reason radial engines have their characteristic firing pattern and slightly uneven piston motion. Pilots and mechanics working with radial engines need to understand this design when interpreting wear patterns, oil consumption, and overhaul procedures.
Intuition Check
Articulated does not mean “spoken clearly” here. It means jointed or hinged so the rod can move through changing angles.
Example Sentence 1
During the radial engine overhaul, the mechanic inspected each articulated connecting rod and its knuckle pin for wear before reassembly.
Example Sentence 2
Radial engines rely on articulated connecting rods so the outer cylinders can reach the same crankshaft without interference.