A thin rod is all that is needed to transmit vibrations from a shaker device (at bottom) and the wingtip of the Active Aeroelastic Wing F/A-18 research aircraft during ground vibration testing at NASA's Dryden Flight Research Center. Wiring hanging down from the wingtip launcher rail transfer signals from accelerometers and other sensors mounted on the wing's upper surface to monitoring equipment. The tests help engineers determine if aerodynamically induced vibrations are controlled or suppressed during flight, and were the last major ground tests prior to the initiation of research flights.