Fiber reinforced composite spar for a rotary wing aircraft

摘要

The present invention discloses a damage tolerant composite article comprising a plurality of layers of both graphite and polyaramide fibers. The graphite fiber layers are oriented at angles of about +/-30 DEG and about +/-15 DEG to the longitudinal axis while the polyaramide fiber layers are oriented at about +/-14 DEG to the longitudinal axis. Composite structures of this construction will have increased damage tolerance while maintaining the required bending and torsional stiffness.