Opel-RAK were a series of rocket vehicles produced by German automobile manufacturer Fritz von Opel, of the Opel car company, in association with others, including Max Valier, Julius Hatry, and Friedrich Wilhelm Sander. Opel RAK is generally considered the world's first large-scale rocket program, significantly advancing rocket and aviation technology as well as instrumental in popularizing rockets as means of propulsion. In addition Opel RAK demonstrations were also highly successful as publicity stunts for the Opel car company. The Lippisch Ente, the world's first rocket-powered glider and piloted for its first flight on June 11, 1928, by Fritz Stamer at Wasserkuppe, was bought and operated by Opel in context of the Opel RAK program but is not formally designated an Opel RAK series number. Also a rocket-powered RAK-Motoclub motorbike, based on a conventional Opel Motoclub 500 SS and presented at the Berlin Motorshow 1928, did not receive a formal RAK number.Opel RAK.1 - a rocket car that achieved 75 km/h (47 mph) in March 1928 and more than 100 km/h in April of the same year Opel RAK.2 - rocket car tested May 23, 1928; reached a speed of 238 km/h (145 mph) driven by 24 solid-fuel rockets Opel RAK.3 - rocket rail vehicle On the second run the vehicle jumped the track and was destroyed. Opel RAK.4 - rocket rail vehicle, destroyed when a solid rocket exploded on the track, exploding all the other rockets. Railway authorities prohibited further runs. Opel RAK.1 - rocket plane flown September 30,

Fritz Adam Hermann von Opel, known as Fritz Adam Hermann Opel until his father was ennobled in 1917, was the only son of Wilhelm von Opel and a grandson of Adam Opel, founder of the Opel company. He is remembered mostly for his Opel RAK demonstrations of the world's first manned rocket-powered ground and air vehicles that earned him the nickname "Rocket Fritz" and which were also highly effective as publicity stunts for his family's automotive business.