Lightning direct effect experimental research on rotor blade of a helicopter

The lightning protection performance of the carbon fiber composite (CFC) main rotor blade of a helicopter is studied by using high-voltage large-current generators. According to the lightning zoning of this helicopter, the blade tip of the main rotor blade was considered belonging to lightning Zone 1A, the blade airfoil part and the blade root of main rotor blade were considered belonging to lightning Zone 2A. In order to achieve the lightning protection for the CFC blade, the blade tip part is protected by covering and bonding copper mesh, the blade leading edge is protected by fully wrapping and bonding metallic sheet wrap till the tip and grounding through a electrical bonding braid at the blade root. To assess the performance of the lightning protection design, simulated lightning strike testing (direct injecting of simulated lightning arc) were conducted for the blade tip part in Zone 1A and the blade airfoil part in Zone 2A, respectively. Coaxial return conductor arrangement which can minimize the magnetic field and magnetic force effect of the return current, and standardized lightning waveforms were employed in the lightning strike testing. Although multiple damages were found in the blade tip part, welded joints of the leading edge metallic wrap and other blade surfaces after the lighting arc injecting and current conducting testing, the mechanical structure integrity and it aerodynamics shape of the main rotor blade were not seriously affected, indicating that the lightning protection design of the main rotor blade is rational and advisable.