Arrays of LEDs are mounted within the tip of windmill wings, each array comprising a plurality of LEDs mounted to printed circuit boards. Additional printed circuit boards assembled over the LED printed circuit boards provide both a radio frequency interference barrier and Faraday cage effect lightning protector. This assembly (lamination) forms assembled core units which then slide into dove tails formed in a central bracket positioned in the wing interior. The bracket also serves as a wing tip spar. The spar, with the assembled core units coupled thereto, slides into channels formed in the interior surfaces of the wing.