Thermoplastic Rotorcraft Driveshafts Provide Weight Reduction with Improved Survivability

A recent Phase II SBIR program focused on improving the survivability of driveshafts in rotorcraft applications while decreasing their weight. Thermoplastic composites were identified as a candidate material for achieving the goals of the program and a design was developed utilizing data from many previous sources and designs. Driveshafts were manufactured and validated against predicted static torque loads after withstanding a ballistic impact. The shafts showed a significant improvement in post-damaged strength over the legacy aluminum design with a weight reduction greater than 30%, exceeding all program goals. Automated Dynamics utilized recent process advancements in manufacturing both test coupons and driveshafts. This process takes advantage of unique aspects of in-situ composite consolidation to improve the bond affected between subsequent plies of pre-impregnated fiber reinforced thermoplastic materials on a continuous basis. Coupon test results demonstrated a 52% reduction in void content and greatly improved mechanical properties, further improving the performance over aluminum and thermoset composite driveshafts.