Hybrid composite for erosion resistant helicopter blades

Abstract

A protective hybrid composite for a rotor blade is based on the use of tape cast ceramic layers densified by pre-ceramic polymer infiltration methods and laminated together with polymer matrix composite prepregs, with or without an embedded metallic mesh, to form a conforming helicopter blade cladding that is laminated to the blade surface for added erosion protection. The hybrid composite is fabricated to net shape and laminated to the blade using either an adhesive or a polymer composite prepreg inner layer. Installation is accomplished by a standard composite fabrication method of vacuum bagging the blade while the system is laminated to its surface. Repair methods based on removal of ceramic tiles is facilitated by incorporation of a metallic mesh element laminated beneath the ceramic tiles that can be used to heat the tile and decrease its adhesion strength.

1 . A method of making a hybrid composite for a helicopter blade comprising:
 tape casting ceramic materials in thin sheets and including an organic binder that renders the thin sheets flexible;   densifying the thin sheets without applied pressure;   forming in a green state the thin sheets into curved ceramic segments formed to net shape;   laminating the thin sheets with polymer composite prepreg layers at low temperature.   
     
     
         2 . The method of  claim 1 , wherein the densifying includes pressureless sintering to full or nearly full density. 
     
     
         3 . The method of  claim 2 , further comprising introducing pre-ceramic polymer infiltrations to aid in the densifying.