The purpose of the Project Rainbow aka the Philadelphia Experiment was Radar invisibility of a Navy ship by counter clockwise Rotating magnetic fields during World War II, which allegedly lead to the deportation of the ship. The principle behind the Philadelphia experiment was the unified field theory developed by Albert Einstein in 1928, which states that Gravity and magnetism are connected like mass and energy are also connected. Tesla Coils (strong electromagnets) were placed at the Navy Ship U.S.S. Eldrige (DE 173) operating at a certain frequency and be able to wrap Gravity around the ship. Dr. Albert Einstein, Dr. John von Neumann and Dr. Nikola Tesla (or at least his technology) was involved in the project. Albert Einstein worked fort he Navy in 1943, a consultancy period by the appointment of Dr. Vannevar Bush.
Anti-Gravity research was conducted in the third Reich by a special united lead by General Hans Kammler. The most known saucer type developed during that time was VRIL and HANEBU. They were alreday powerd by moving magnetic fields.