D. Barwey et Gh. Gaonkar, DYNAMIC-STALL AND STRUCTURAL-MODELING EFFECTS ON HELICOPTER BLADE STABILITY WITH EXPERIMENTAL CORRELATION, AIAA journal, 32(4), 1994, pp. 811-819
The effects of blade and root-flexure elasticity and dynamic stall on
the stability of hingeless rotor blades are investigated. The dynamic
stall description is based on the ONERA models of lift, drag, and pitc
hing moment. The structural analysis is based on three blade models th
at range from a rigid flap-lag model to two elastic nap-lag-torsion mo
dels, which differ in representing root-flexure elasticity. The predic
tions are correlated with the measured lag damping of an experimental
isolated three-blade rotor; the correlation covers rotor operations fr
om near-zero-thrust conditions in hover to highly stalled, high-thrust
conditions in forward flight. That correlation shows sensitivity of l
ag-damping predictions to structural refinements in blade and root-fle
xure modeling. Moreover, this sensitivity increases with increasing co
ntrol pitch angle and advance ratio. For high-advance-ratio and high-t
hrust conditions, inclusion of dynamic stall generally improves the co
rrelation.