The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 10, 1977
Filed:
Nov. 06, 1975
Jan M Drees, Dallas, TX (US);
Arthur D Gravley, Euless, TX (US);
Charles V Palachek, Smithfield, TX (US);
James L Spencer, Arlington, TX (US);
Textron, Inc., Providence, RI (US);
Abstract
A helicopter main rotor has blades with an inboard airfoil having a high lift-drag ratio for efficient hovering and a 'shock-free' outboard airfoil for high speed cruise. Each rotor blade has a structural section composed of metal spars and metal skins forming torque boxes accompanied by a nonstructural fairing and after body. Secured within the torque boxes and the after body are honeycomb cellular structures of a metallic and nonmetallic material, depending on the area wherein the cellular structure is secured. At a point along the blade radius, between 60% and 75%, the upper metal skin of the aft torque box changes from an outer contour surface of the blade to a flat surface parallel to and above the cord line. A fairing of fiberglass skin is secured over a nonmetallic cellular structure over the flat surface of the upper metal skin to complete the upper outer airfoil contour outboard of the 75% radius dimension. The lower outer airfoil contour is the metal skin of the aft torque box followed by a fiberglass skin joined at a trailing edge with the fiberglass upper surface.