Reinforced plastic blades
Abstract
Abstract A HELICOPTER ROTOR BLADE COMPRISES A THIN SECTION HOLLOW STEEL SPINE ATTACHED TO A ROOT SECTION AND WITH A FIBRE GLASS SHEATH MOULDED ON TO IT TO GIVE THE REQUIRED PROFILE. SECTIONS OF THE SHEATH ARE CUT AWAY AND FAIRED BY METAL SHEETING TO PROVIDE FLUID DUCTS EXTENDING ALONG THE BLADE. SLOTS FORMED IN THE METAL SHEETING ENABLE AIR TO BE DISCHARGED OVER THE BLADE SURFACE FOR CIRCULATION CONTROL PURPOSES. THE DUCTS AND SLOTS ARE IN THREE SEPARATE SPANWISE SECTIONS, OF WHICH THE OUTER TWO ARE SUPPLIED WITH AIR PASSING ALONG THE HOLLOW SPINE WHICH IS SUITABLY PROVIDED WITH BAFFLES. HIGH TENSILE STEEL WIRES EXTENDING AXIALLY THROUGH THE SHEATH AND ATTACHED TO THE ROOT SECTION AND THE SPINE IN THE REGION OF THE BLADE LIP ACT TO RESTRICT BLADE FLEXING AND ANY CONSEQUENT DISTORTION OF THE SLOTS. THE USE OF CARBON OR OTHER FIBRES IS ENVISAGED AS ARE VARIATIONS IN THE DIRECTION OF THE LAY OF THE FIBRES, INCLUDING A LATTICE STRUCTURE.
Inventors
- 👤 Ian Clifford Cheeseman
- 👤 Charles Reginald Lawrence
- 👤 Thomas George Holmes Woolford
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |