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US 5,269,657 AGranted
Aerodynamically-stable airfoil spar
OwnerMarvin Garfinkleinventor
Life of this patent
Estimating the term…
Abstract
A structural spar is provided that provides beneficial flexural-torsional coupling to an airfoil so that flexural excursions of the airfoil induces torsion in the spar so as to change the pitch angle of the airfoil in such a manner as to the oppose the flexure, thereby ameliorating the excursion.
Claims27
In a spar of the type having a neutral plane, a normal bending axis and a longitudinal axis, the method of applying a torsional-flexural coupling to said spar after it is bent comprising the steps of
- creating a second bending axis which is skewed from said normal bending axis by providing at least two essentially helical windings that extend longitudinally along said spar, said essentially helical windings essentially mirror images of each other, said second bending axis being the actual bending axis of said spar,
- thereby when said spar is bent the bending imparts a torsional-flexural coupling about said longitudinal axis,
- whereupon said torsional-flexural coupling is applied over the length of said spar.
A spar of the type having a neutral plane, a normal bending axis and a longitudinal axis,
- said spar comprising a core having a plurality of sections, and
- an actual bending axis, said actual bending axis being skewed from said normal bending axis so that when said spar is bent a torsional-flexural coupling is induced about said longitudinal axis over the length of said spar.
Dependencies are inferred from the claim text.