Science Fair Project Encyclopedia
A spar is a round timber or metal pole used on a sailing ship. Masts, booms, gaffs, or yards are all examples of spars. Wooden ships from the age of sail often carried many extra spars of all types for repairs while at sea. The spar deck of a frigate was called such as it was used to carry spare spars.
In an aircraft, the spar is the main structural member of the wing, running lengthways across the span of the wing, at right angles (or thereabouts) to the fuselage. The spar carries all of the forces of both lift, and the weight of the wings on the ground. Other structural and forming members such as ribs may be attached to the spar or spars. There may be more than one spar in a wing, though in general one carries the majority of the forces on it, and is called the main spar.
Spar is a term employed to include a great number of crystallized, earthy, and some metallic substances, which easily break into rhomboidal, cubical, or laminated fragments with polished surfaces, but without regard to the ingredients of which they are composed. Among miners the term is frequently used alone to express any bright crystalline substance.
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