Patent US4580944A successfully refreshed from Google Patents.
US4580944A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aerodynamic flexible fairing
Assignee: Sumitomo Heavy Industries Ltd
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Filing: 1984-05-15
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Granted: 1986-04-08
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Expires: 2004-05-15
Abstract
Abstract The present invention is a flexible fairing for covering rotor connections on a rotor wing aircraft. Such a fairing would comprise a flexible polyurethane foam material which could maintain its aerodynamic shape while in flight yet be compliant enough to allow for changes in blade pitch without adding significant torsional stiffness to the connector. In addition, a flexible urethane rubber coating may be used to protect the foam fairing for abrasion or moisture absorption.
Inventors
- 👤 Gordon G. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 02:09
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/55
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
108 words
In a rotary wing aircraft having a flexible rotor connector comprising one or more flexbeams, a pitch shaft and a means for applying torque to the shaft to alter the pitch of the rotor wherein said flexbeams and pitch shaft are enclosed in a torsionally compliant, aerodynamic fairing which is capable of maintaining an aerodynamic shape during flight, protect the enclosed flexbeams and pitch shaft from damage due to debris while being sufficiently compliant to allow the outboard end to rotate through a pitch change of up to about +30 degrees to the normal axis without cracking or significantly contributing to the torsional stiffness of the rotor connector.
Claim 2
Dependent Claim
108 words
In a rotary wing aircraft having a flexible rotor connector comprising one or more flexbeams, a pitch shaft and a means for applying torque to the shaft to alter the pitch of the rotor wherein said flexbeams and pitch shaft are enclosed in a torsionally compliant, aerodynamic fairing which is capable of maintaining an aerodynamic shape during flight, protect the enclosed flexbeams and pitch shaft from damage due to debris while being sufficiently compliant to allow the outboard end to rotate through a pitch change of up to about +30 degrees to the normal axis without cracking or significantly contributing to the torsional stiffness of the rotor connector.
Claim 3
Dependent Claim
15 words
The article of claim 1 wherein the compliant fairing is formed of a urethane foam.
Claim 4
Dependent Claim
22 words
The article of claim 1 wherein the compliant urethane foam has a compressive modulus of about 50 psi to about 175 psi.
Claim 5
Dependent Claim
19 words
The article of claim 1 wherein the compliant fairing has an outer coating of an erosion resistant polyurethane rubber.
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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) | 1989-04-07 | 1989-10-07 | 1990-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-07 | 1993-10-07 | 1994-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-07 | 1997-10-07 | 1998-04-08 | $7700.00 | Window Closed / Lapsed |