 Modern biplane designs still exist in specialist roles such as aerobatics and agricultural aircraft with the competition aerobatics role and format for such a biplane well-defined by the mid-1930s by the Udet U 12 Flamingo and Waco Taperwing.The Pitts Special dominated aerobatics for many years after World War II and is still in production.The vast majority of biplane designs have been fitted with reciprocating engines.