U.S. patents available from 1976 to present.
U.S. patent applications available from 2005 to present.

Hingeless and bearingless multiblade rotor for rotary wing aircraft

Patent 4344739 Issued on August 17, 1982. Estimated Expiration Date: Icon_subject April 25, 2000. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Patent References

3879153

Hingeless helicopter rotor with improved stability
Patent #: 3999886
Issued on: 12/28/1976
Inventor: Ormiston ,   et al.

Rotor without flapping hinges and without lead-lag hinges
Patent #: 4201515
Issued on: 05/06/1980
Inventor: Derschmidt ,   et al.

Multi-blade propellers Patent #: 4281966
Issued on: 08/04/1981
Inventor: Duret ,   et al.

Inventors

Assignee

Application

No. 06/143628 filed on 04/25/1980

US Classes:

416/141, Plural articulation416/134AAircraft rotors

Examiners

Primary: Powell, Everette A. Jr.

Attorney, Agent or Firm

International Classes

B64C 27/32 (20060101)
B64C 27/33 (20060101)

Foreign Application Priority Data

1979-05-16 DE

Abstract

The wing blades of a hingeless and bearingless multiblade rotor are connected to a substantially rigid rotor hub by spar sections elastically twistable and bendable in the flapping direction and in the lead-lag direction. The mounting positions on the periphery of the rotor hub for connection of the spar sections of the respective blades are off-set relative to the angular position of the corresponding blades to which they are connected. Further, the mounting positions for the spar sections of each rotor blade are situated on the periphery of the half side or far side of the rotor hub, facing away from the respective rotor blade. A rear spar section of each mounted rotor blade with reference to the direction of rotation, overlaps the front spar section of the immediately following rotor blade but with free clearance and spacing between the overlapping spar sections in the direction of the rotor axis so that the maximum bendable length of the elastic spar sections is afforded without interference between the blades. The effective or virtual flapping hinges and lead-lag hinges of each blade is shifted closer to the rotor axis thereby minimizing the masses necessary for propeller moment compensation, and static and dynamic balancing of the rotor blades, as well as reducing the required steering forces.

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