Analytical flutter investigation of a composite propfan model

T h i s paper p resen ts a t h e o r e t i c a l model and an a s s o c i a t e d computer program f o r p r e d i c t i n g subsonic bend ing to rs ion f l u t t e r i n p rcp fans . The model i s based on two-dimensional uns teady cascade s t r i p t h e o r y and th ree-d imens iona l s teady and unsteady l i f t i n g s u r f a c e aerodynamic t h e o r y i n c o n j u n c t i o n w i t h a f i n i t e e lement s t r u c t u r a l model f o r t h e b lade. The a n a l y t i c a l r e s u l t s compare w e l l w i t h p u b l i s h e d exper imen ta l da ta . A d d i t i o n a l param e t r i c s t u d i e s a r e a l s o p resen ted i l l u s t r a t i n g t h e e f f e c t s on f l u t t e r speed o f s teady a e r o e l a s t i c de fo rma t ions , b l a d e s e t t i n g angle, r o t a t i o n a l speed, number o f b lades, s t r u c t u r a l damping, and number o f modes. 2