Abstract: A radar cross-section reduction system utilizes a charging device for creating a high positive DC static potential on an object such as an aircraft. The charging system is mounted to the object so that this DC potential would be applied to the outer skin or surface of the object. The charging system includes Van de Graaf generators located in housings attached to the object. Each Van de Graaf generator has two pulleys about which a belt is rotated. One of the pulleys and the belt are nonconductors, while the other pulley is a conductor. This results in a buildup of positive charges at one end of the belt and negative charges at the other end. The negative charges are picked off and applied to a ground section. The positive charges are picked off and applied to a collector. The collector is in electrical continuity with the outer structure of the object. Negative dissipators attached to the ground section dissipate the excess negative charges during flight.

Abstract: An aircraft has an exhaust flame or plume which can be modulated to communicate. A sound emitter is mounted to the aircraft for emitting acoustic waves into the exhaust plume. An encoder will control the emitter at selected digital sequence to provide a digital message. The flame or plume will radiate at a frequency range of interest depending on the type of aircraft. The sound waves cause the frequencies to change from a continuous spectrum to a spectrum which has a much lower amplitude. A detector remotely located from the aircraft will detect radiation. It filters frequencies outside of the frequency range of interest. It will discriminate between the modulated pattern and the continuous pattern. This output provides the digital code that was encoded by the encoder. A decoder will decode the message for the recipient.