The influence of balanced anisotropy in elastic, inertial, and aerodynamic properties on the aeromechanical stability of a soft-in-plane rotor is examined. Balanced anisotropy will not produce large 1/rev vibratory loads experienced when one blade is dissimilar. Dissimilarities in flap stiffness, lag dampers, and aerodynamic properties have virtually no influence on the minimum damping. Dissimilarities in blade radius, mass, and lag stiffness are most effective in improving aeromechanical stability. Stability continues to improve as the degree of balanced anisotropy increases unlike the case of one dissimilar blade. A 20 % reduction in the radius of two opposite blades is able to stabilize ground resonance at 0-deg collective. For balanced anisotropy in radius, the destabilizing trend at roll resonance with increasing collective and decreasing body roll inertia is diminished. Balanced anisotropy in radius is less effective in stability augmentation for an articulated rotor. Appropriately combining dissimilarity in radius and lag stiffness can result in additional benefits for aeromechanical stability if the initial levels of anisotropy are moderate to small.
Influence of balanced rotor anisotropy on helicopter aeromechanical stability
Einfluß der anisotropen Flügelblattanordnung auf die aeromechanische Stabilität eines Helikopters
AIAA Journal ; 37 , 10 ; 1152-1160
1999
9 Seiten, 21 Bilder, 1 Tabelle, 26 Quellen
Aufsatz (Zeitschrift)
Englisch
Abmessung (Auslegung) , Abreißen der Strömung , Aerodynamik , Anisotropie , Antriebsleistung , Aufhängung , Auf-und-Ab-Bewegung , Drehschwingung , dynamische Stabilität , Flatterschwingung , Flügelblatt , Hubschrauber , Kippschwingung , mathematisches Modell , mechanischer Wirkungsgrad , Optimalwert , Phasendifferenz , Resonanz , Rotor (Drehflügel) , Schwingungsdämpfung , Schwingungsfrequenz , Schwingungsverhalten , Steifigkeit
Influence of Balanced Rotor Anisotropy on Helicopter Aeromechanical Stability
British Library Conference Proceedings | 1997
|