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:
Feb. 20, 2001
Filed:
Sep. 24, 1999
Eiichi Yamakawa, Kakamigahara, JP;
Atsushi Murashige, Kakamigahara, JP;
Tomoka Tsujiuchi, Kakamigahara, JP;
Abstract
A blade root portion of a rotor blade is attached to a rotor head for rotating. A center portion linearly elongates from the blade root portion. A blade tip portion outward elongates from the center portion and has a shape which is defined by a leading edge, a side edge and a trailing edge, and has a predetermined aerofoil. In the leading edge of the blade tip portion, a swept-back angle &lgr;(r) at a distance r from the rotation center of a rotor satisfies relational expression (1) of a rotor blade length R of a rotorcraft, a maximum flight Mach number M,which is a flight limit speed of the rotorcraft, a blade tip Mach number M,which is a tip speed during hovering, and a drag divergence Mach number M,which is determined from the aerofoil of the blade tip portion. According to this configuration, it is possible to provide a rotor blade for a rotorcraft in which the performance in high-speed flying is improved, the high-speed impulsive noise can be reduced, and a high control performance is attained.