Abstract: Unmanned aerial vehicles are provided. In one aspect, the unmanned aerial vehicle includes a four-bar linkage mechanism in mechanical communication with a pair of wings. An electrical subsystem includes an actuator in mechanical communication with the four-bar-linkage mechanism. The actuator is in electrical communication with a capacitor. A plurality of solar panels is in electrical communication with the capacitor, which is configured to harvest non-battery energy from the plurality of solar panels to power the actuator for controlling the four-bar linkage mechanism to operate the pair of wings.