A young man was killed today in a Brooklyn park, when the blades of one of his remote-controlled copters scalped him, sources say. Roman Pirozek, 19, was flying the chopper at Calvert Vaux Park in Gravesend, when he lost control of the toy aircraft around 3:40 p.m., law enforcement source told The Post. The aircraft boomeranged and sliced off the top of his head – while people watched in horror. “I was playing at the park and we came into the clearing and we just saw a body on the floor, he was just decapitated, the whole top of his head was gone,” said Maria Delgado, 13. Pirozek was pronounced dead at the scene, the FDNY said. RIP!