Gears with an asymmetric involute gear tooth form were analyzed to determine their bending and contact
stresses relative to symmetric involute gear tooth designs which are representative of helicopter main drive
gears. Asymmetric and baseline (symmetric) toothed gear test specimens were designed, fabricated and
tested to experimentally determine their single-tooth bending fatigue strength and scuffing resistance. Also,
gears with an analytically optimized root fillet form were tested to determine theirsingle-tooth bending fatigue
characteristics relative to baseline specimens with a circularroot fillet form. Test results demonstrated higher
bending fatigue strength for both the asymmetric tooth form and optimized fillet form compared to baseline
designs. Scuffing resistance was significantly increased for the asymmetric tooth form compared to a
conventional symmetric involute tooth design.