The use of warning lights on aircraft is well known. Such lights are typically attached to aircraft extremities such as wing tips or tail sections and are illuminated at night so that the aircraft can be seen. Warning lights for helicopters pose a slightly different problem than for fixed wing aircraft in that the outer extremities of a helicopter are mostly defined by its whirling rotor blade.
It goes without saying that helicopters are highly maneuverable aircraft and certain kinds of rescue and/or military operations involve their use in areas where space is limited, perhaps by the existence of trees, buildings, or the presence of other helicopters. A person familiar with helicopter technology knows that collision of a rotor blade with virtually anything is typically a catastrophic event. It is important, therefore, that the helicopter operator or pilot is aware of the position of the blade's outer perimeter. During night operations it is difficult or impossible for the pilot to accurately determine this, which has been known to cause numerous accidents.
Past attempts have been made at solving this problem by placing electric lights at the rotor's tip so that the blade's perimeter is easily visible. Also, there have been attempts to develop tip-mounted radar devices which electronically sense objects near the rotor, such as the device disclosed in U.S. Pat. No. 4,737,788. However, these attempts have not met with practical results, primarily because it is difficult to design relatively complex electrical systems that can structurally weather the high forces present on the rotor blade as it whirls. As will become apparent, the present invention provides a simple, workable design that is believed to be the first practical device known in the art for placing warning lights at the blade's tip.