Abstract: A method for reducing a nose-up pitching moment in an unmanned aerial vehicle during forward flight. The unmanned aerial vehicle includes counter-rotating rotor assemblies that are mounted within a duct. Each rotor assembly includes a plurality of rotor blades. The method involves adjusting the rotor blades to have substantially zero pitch. Then rotating the rotor assemblies to produce a virtual plane across the duct. The virtual plane is operative for substantially deflecting air passing over the fuselage away from the duct. In one embodiment of the invention, the method involves the further step of obstructing at least a portion of the bottom of the duct to inhibit air that is flowing across the bottom of the duct from passing into the duct.

Abstract: A dimmer panel for controlling the intensity of a plurality of electric light sources includes a plurality of dimming circuits. Each dimming circuit has a control circuit, a heat producing controllably conductive power switch such as a triac, and a heat producing coil such as a choke. The power switches and coils are arranged on a corrugated heat sink to minimize component temperatures in the dimming control circuit and of the power switches. The heat producing coils are remotely located from the control circuit and the power switches, so that the heat generated by the coils does not increase the temperature of the components in the control circuit or of the power switches.