The influence of unsteady aerodynamic effects on the coupled free vibrations of rotor flapping and body pitch and roll in hover

Journal of the American Helicopter Society

Volumn 41, Issue 3, 1996, Pages 208-218

  Rosen, A ^a   Isser, Ahron ^a  

^a TECHNION ISRAEL INSTITUTE OF TECHNOLOGY   (Israel)

Author keywords

[No Author keywords available]

Indexed keywords

AERODYNAMICS; DAMPING; FLIGHT DYNAMICS; MATHEMATICAL MODELS; NATURAL FREQUENCIES; STABILITY; UNSTEADY FLOW; VIBRATIONS (MECHANICAL);

AEROMECHANICAL STABILITY; COUPLED FREE VIBRATIONS; FLAP REGRESSING MODE; UNSTEADY AERODYNAMIC EFFECTS;

HELICOPTER ROTORS;

EID: 0030191860     PISSN: 00028711     EISSN: None     Source Type: Journal    
DOI: 10.4050/jahs.41.208     Document Type: Article

References (28)

1. Lytwyn, R.T., Miao, W. and Woitch, W., "Airborne and Ground Resonance of Hingeless Rotors," Journal of the American Helicopter Society, Vol. 16, (2), 1971, pp. 2-9.
2. Donham, R.E., Cardinale, S.Y. and Sachs, I.B., "Ground and Air Resonance Characteristics of a Soft Inplane Rigid Rotor System," Journal of the American Helicopter Society, Vol. 14, (4), 1969, pp. 33-41.
3. Orniston, R.A., Warmhrodt, W.G., Hodges, D.H. and Peters, D.A., "Survey ofArmy/NASA Rotorcraft Aeroelastic Stability Research," NASA TM 101026, Oct 1988.
4. Hodges, D.H., Hopkins, A.S., Kunz, D.L. and Hinnant, H.H., "Introduction to GRASP - General Rotorcraft Aeromechanical Stability Program - A Modern Approach to Rotorcraft Modeling," Journal of the American Helicopter Society, Vol. 32, (2), 1987, pp. 78-90.
5. Rutkowski, M.J., Ruzicka, G.G., Ormiston, R.A., Saberi, H. and Jung, Y., "Comprehensive Aeromechanics Analysis of Complex Rotorcraft Using 2GCHAS," Journal of the American Helicopter Society, Vol. 40, (4), 1995, pp. 3-17.
6. Ormiston, R. A., "Rotor-Fuselage Dynamics of Helicopter Air and Ground Resonance," Journal of the American Helicopter Society, Vol. 35, (2), 1991, pp. 3-20.
7. Zhang, X., "Investigation of Helicopter Air Resonance in Hover by Complex Coordinates and Mutual Excitation Analysis," Journal of the American Helicopter Society, Vol. 38, (2), 1993, pp. 15-24.
8. Milgram, J.H. and Chopra, I., "Air Resonance of Hingeless Rotor Helicopters in Trimmed Forward Flight," Journal of the American Helicopter Society, Vol. 39, (4), 1994, pp. 46-58.
9. Zotto, M.D. and Loewy, R.G., "Influence of Pitch-Lag Coupling on Damping Requirements to Stabilize Ground/Air Resonance," Journal of the American Helicopter Society, Vol. 37, (4), 1992, pp. 68-71.
10. Smith, E.C. and Chopra, I., "Air and Ground Resonance of Helicopters with Elastically Tailored Composite Rotor Blades," Journal of the American Helicopter Society, Vol. 38, (4), 1993, pp. 50-61.
11. Gandhi, F. and Chopra, I., "An Analytical Model for a Nonlinear Elastomeric Lag Damper and Its Effect on Aeromechanical Stability in Hover," Journal of the American Helicopter Society, Vol. 39, (4), 1994, pp. 59-69.
12. Wang, J.M. and Chopra, I., "Dynamics of Helicopters with Dissimilar Blades," Proceedings of the 47th Annual Forum of the American Helicopter Society, Phoenix, AZ, May 1991, pp. 1399-1412.
13. Flowers, G.T. and Tongue, B.H., "Nonlinear Behavior of a Rotorcraft Model During Air Resonance," Journal of Vibration and Acoustics, Vol. 113, 1991, pp. 141-151.
14. Takahashi, M.D. and Friedmann, P.P., "Helicopter Air Resonance Modeling and Suppression Using Active Control," Journal of Guidance and Control, Vol. 14, (6), 1991, pp. 1294-1300.
15. Juggins, P.T.W., "Substantiation of the Analytical Prediction of Ground and Air Resonance Stability of a Bearingless Rotor, Using Model Scale Tests," Vertica, Vol. 14, (3), 1990, pp. 301-312.
16. Lim, J.W. and Anastassiades, T., "Correlation of 2GCHAS Analysis with Experimental Data," Journal of the American Helicopter Society, Vol. 40, (4), 1995, pp. 18-33.
17. Bousman, W.G., "An Experimental Investigation of the Effects of Aeroelastic Couplings on Aeromechanical Stability of a Hingeless Rotor Helicopter," Journal of The American Helicopter Society, Vol. 26, (1), 1981, pp. 46-54.
18. Hodges, D.H., "An Aeromechanical Stability Analysis for Bearingless Rotor Helicopters," Journal of the American Helicopter Society, Vol. 24, (1), 1979, pp. 2-9.
19. Friedmann, P.P. and Venkatesan, C., "Coupled Rotor/Body Aeromechanical Stability Comparison of Theoretical and Experimental Results," Journal of Aircraft, Vol. 22, (2), 1985, pp. 148-155.
20. Johnson, W., "Influence of Unsteady Aerodynamics on Hingeless Rotor Ground Resonance," Journal of Aircraft, Vol. 19, (8), 1982, pp. 668-673.
21. Friedmann, P.P. and Venkatesan, C, "Influence of Unsteady Aero-dynamic Models on Aero-mechanical Stability in Ground Resonance," Journal of the American Helicopter Society, Vol. 31, (1), 1986, pp. 65-74.
22. Rosen, A. and Isser, A., "The Influence of Variations in the Locations of the Blades on the Loads of a Helicopter Rotor During Perturbations About an Axial Flight," TAE Report No. 721, Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa, Israel, Oct 1994.
23. Isser, A. and Rosen, A., "A Model of the Unsteady Aerodynamics of a Hovering Helicopter Rotor that Includes Variations of the Wake Geometry," Journal of the American Helicopter Society, Vol. 40, (3), 1995, pp. 6-16.
24. Rosen, A. and Isser, A., "A New Model of Rotor Dynamics During Pitch and Roll of a Hovering Helicopter," Journal of the American Helicopter Society, Vol. 40, (3), 1995, pp. 17-28.
25. Rosen, A., Isser, A. and Yoshpe, M., "The Influence of Unsteady Aerodynamics and Inter-Blade Aerodynamic Coupling on the Blades Response to Harmonic Variations of Their Pitch Angles," The Aeronautical Journal, Vol. 100 (991), 1996, pp. 27-35. Also Proceedings of the Twentieth European Rotorcraft Forum, Amsterdam, The Netherlands, 4-7 Oct 1994, Paper No. 74.
26. Rosen, A., Isser, A. and Yoshpe, M., "The Influence of Unsteady Aerodynamics and Inter-Blade Aerodynamic Coupling on the Blades Response to Harmonic Variations of Their Pitch Angles," The Aeronautical Journal, Vol. 100 (991), 1996, pp. 27-35. Also Proceedings of the Twentieth European Rotorcraft Forum, Amsterdam, The Netherlands, 4-7 Oct 1994, Paper No. 74.
27. Rosen, A. and Isser, A., "A New Unsteady Aerodynamic Model of the Coupled Rotor-Body Dynamics," TAE Report No. 728, Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, March 1995.
28. Rosen, A. and Isser, A., "A New Unsteady Aerodynamic Model of the Coupled Rotor-Body Dynamics," Proceedings of the American Helicopter Society 51st Annual Forum, Fort Worth, TX, May 9-11, 1995.