Composite flexbeam for a bearingless helicopter rotor

• US 5,096,380 A
• Filed: 05/03/1990
• Issued: 03/17/1992
• Est. Priority Date: 05/03/1990
• Status: Expired due to Fees

• Current Assignee: United Technologies Corporation (Rtx Corporation)
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: Byrnes, Francis E., Krauss, Albert T.
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): LARSON, JAMES
• Application Number:
  US07/518,592
• Time in Patent Office: 684 Days
• Field of Search: 416/134 A, 416/138 A, 416/141, 416/230 A
• US Class Current: 416/134.00A
• CPC Class Codes: B29D 99/0003 Producing profiled members, e.g. beams
• CPC Class Codes: B64C 27/33 having flexing arms

Abstract

A flexbeam 16 for a bearingless helicoptor rotor includes a composite beam 28, composed of unidirectional fibers bound in an epoxy matrix, having ribs 32, composed of unidirectional fibers bound in a urethane matrix, bonded to each horizontal face at the section of the beam 28 which accommodates lead-lag torsion.

Claims

1. A flexbeam for a helicopter rotor system comprising:

a beam of unidirectional composite fibers extending longitudinally along the length of said beam and bound in an epoxy matrix and having two horizontal faces and two vertical faces, a hub section, a flap flexure section outboard of said hub section, a lag-torsion section outboard of said flap flexure section, and a blade attachment section outboard of said lag-torsion section; and

a rib of unidirectional composite fibers bound in a urethane matrix and extending longitudinally along the length of said rib and longitudinally of said beam and bonded to one of said horizontal faces of said beam at said lag-torsion section.

2. The flexbeam according to claim 1, wherein both of said horizontal faces have a said rib bonded thereto.

3. The flexbeam according to claim 1 wherein said rib is characterized by tapering down in thickness at each end.

4. The flexbeam according to claim 1, wherein said beam has a rectangular cross-section and is characterized by the width and thickness of said beam tapering down through said flap flexure section, staying constant through the majority of said lag-torsion section and tapering up at the outboard end of said lag-torsion section to the blade attachment section.

5. The flexbeam according to claim 2 wherein each said rib is characterized by tapering down in thickness at each end.