Definition
An aircraft structural framework built from rigid members — typically tubes or rods — joined to form a rigid skeleton of triangles. Loads are carried by the framework itself through tension and compression in the individual members, with the outer covering (fabric or thin metal) carrying little or no structural load.
Plain English
A skeleton-style airframe made of straight metal tubes welded into a frame of triangles. The tubes carry the weight and stress; the skin on the outside is just a cover.
Context Anchor
Seen in airframe structure discussions, especially older or fabric-covered aircraft fuselages and welded tube frames.
Derivation
From the Old French trousse, meaning a bundle or pack tied together. In engineering, a truss became the name for a rigid frame of members tied together to share a load — the same idea seen in bridges and roof rafters.
Why Pilots Care
Knowing the structure type matters during preflight and maintenance. On a truss-type airframe, damage to a tube is structural damage, even if the fabric or skin still looks fine. Repairs and inspections focus on the frame underneath, not just the surface.
Analogy
Think of a steel-tube bicycle frame. The triangles of tubing carry all the load; any paint or wrap on top is just cosmetic.
Intuition Check
Do not assume the outer skin or fabric is what makes a truss-type structure strong. In this design, the internal framework carries the main loads.
Example Sentence 1
The Piper Cub uses a welded steel-tube truss-type structure covered with fabric.
Example Sentence 2
Early fabric-covered airplanes often relied on a truss-type structure to keep the fuselage rigid.