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Perturbation solutions for the influence of forward flight on helicopter rotor flapping stability
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Johnson, W. |
| Copyright Year | 1974 |
| Description | The stability of the flapping motion of a helicopter rotor blade in forward flight is investigated, using a perturbation technique which gives analytic expressions for the eigenvalues, including the influence of the periodic aerodynamic forces in forward flight. The perturbation solutions are based on small advance ratio (the ratio of the helicopter forward speed to the rotor tip speed). The rotor configurations considered are a single, independent blade; a teetering rotor; a gimballed rotor with three, four, and five or more blades; and a rotor with N independent blades. The constant coefficient approximation with the equations and degrees of freedom in the nonrotating frame represents the flap dynamic reasonably well for the lower frequency modes, although it cannot, of course, be completely correct. The transfer function of the rotor flap response to sinusoidal pitch input is examined, as an alternative to the eigenvalues as a representation of the dynamic characteristics of the flap motion. |
| File Size | 4279900 |
| Page Count | 108 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19740023388 |
| Archival Resource Key | ark:/13960/t9r25qg14 |
| Language | English |
| Publisher Date | 1974-08-01 |
| Access Restriction | Open |
| Subject Keyword | Aircraft Numerical Analysis Aerodynamic Configurations Flapping Hinges Eigenvalues Performance Prediction Rotor Aerodynamics Aerodynamic Forces Rotary Wings Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
