A X-wing flapping-wing mechanism with wings flapping symmetrically is designed. The crank slider mechanism is adopted to convert the circular motion of the crank into the linear reciprocating motion of the straight shaft. and the straight shaft drives the wings on both sides through the rocker to realize the symmetric flapping of the wings. A prototype of the flapping-wing mechanism i... https://www.chiggate.com/jerome-brown-philadelphia-eagles-mitchell-ness-1990-legacy-jersey-discount/