Definition
A short connecting rod used in a radial engine to attach an articulating piston to the master rod, rather than directly to the crankshaft. The link rod pivots on a knuckle pin set into a flange on the master rod, allowing each articulating piston to follow its cylinder's motion while the master rod alone rides the crankpin.
Plain English
In a radial engine, only one piston connects straight to the crankshaft through the master rod. All the other pistons are tied to that master rod by short rods called link rods. The link rod is what lets each of the other pistons push and pull on the master rod as the engine turns.
Context Anchor
Seen in radial engine construction, especially in diagrams of the master-and-link rod assembly.
Derivation
From 'link,' meaning a connecting piece that joins two parts so they can move together. The name describes its job: it links a piston to the master rod.
Why Pilots Care
Link rods carry combustion loads from every cylinder except the master cylinder. If a knuckle pin or link rod fails in flight, the engine can seize or shed parts. Mechanics inspect link rod bushings and knuckle pins carefully during radial engine overhauls.
Intuition Check
Do not read link rod as just any rod that connects two parts. In this engine context, it means a specific secondary connecting rod attached to the master rod in a radial piston engine.
Example Sentence 1
During the radial engine teardown, the technician removed each link rod from the master rod flange and inspected the knuckle pin bushings for wear.
Example Sentence 2
Each link rod in the radial engine swings on the master rod to keep piston motion synchronized.