Thomas Townsend Brown has been flying his own secret design of a metal disc for more than 30 years. The biggest reached about 30 inches in diameter. The discs were tethered to a mast or pole and the thin double discs flies in a circle around the pole all by itself. While flying it gave a low humming sound and it glowed in the dark with an eerie lavender light indicating their power which is a kind of electricity. The force that keeps the disc in the air is called "Electric Wind"