Definition
Rigid vertical or near-vertical structural members on a biplane that connect the upper wing to the lower wing, holding them apart at the correct spacing and helping carry flight loads between the two wings.
Plain English
The upright posts between the upper and lower wings of a biplane that hold the wings apart and tie them together as one structure.
Context Anchor
Seen in discussions of biplane structure, aircraft restoration, preflight inspection of older aircraft, and wing bracing.
Derivation
From Latin 'inter' meaning 'between' and 'plane' (short for aeroplane, referring to a wing surface), plus 'strut' from Old English meaning a rigid supporting bar. Together: a supporting bar between the wings.
Why Pilots Care
They preserve wing alignment and structural integrity under aerodynamic loads; loose or damaged struts can lead to wing distortion or failure.
Analogy
They are like the braces between shelves in a frame: they help keep the two surfaces spaced correctly and able to carry loads without shifting.
Intuition Check
Do not confuse interplane struts with landing gear struts. Interplane struts are between wings, not between the airplane and the wheels.
Example Sentence 1
During the preflight on the Stearman, the pilot checked each interplane strut for cracks and secure attachment at the upper and lower wing fittings.
Example Sentence 2
During restoration the crew replaced the original wooden interplane struts with metal ones for added strength.