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Electrostatic Theory Applied to Helicopter Discharging,
NAVAL RESEARCH LAB WASHINGTON DC
An electrostatic analysis is made of a hovering vehicle out of electrical contact with the ground. Charging of the vehicle is seen to be accomplished by a variety of mechanisms. Engine exhausts are strongly ionized and, since they are physically localized at the stacks, can be modulated to produce vehicle charging. Strong charging can result from the frictional contact of dust, ice, or water particles with the vehicle skin and the processes of conduction and diffusion will operate to remove net charge from any isolated object. The electrostatics of an isolated body above a ground plane are reviewed and developed. The dynamics of the discharge process are next addressed. In the process of summarizing the results presented, several possible solutions to the grounding problem are suggested. All rely on establishing initial ground contact through a controlled non-zero resistive path in order to limit the magnitude and steepness of the current discharge pulse. Upon accomplishment of this initial attachment, existing grounding techniques may be profitably employed. It is suggested that existing specifications and procedures be assessed to determine their usefulness in the light of this analysis.
This article is from 'International Aerospace and Ground Conference on Lightning and Static Electricity (8th): 'Lightning Technology Roundup,' held at Fort Worth, Texas on 21-23 June 1983,' AD-A135 100, p60-1 thru 60-8.