Opel RAK.1

The Opel RAK 1, introduced in 1928, was the first rocket‑propelled aircraft built by the German automobile manufacturer Opel as part of its pioneering RAK (Raketensport) program. Engineer Fritz von Opel, son of the company’s founder, collaborated with rocket pioneer Max Valier and aeronautical designer Julius Hatry to mount a small liquid‑fuel rocket motor on a modified glider fuselage. The aircraft’s airframe was a lightweight wooden monoplane with a 15‑meter wingspan, open cockpit and tail‑plane that could be detached for ground transport. Its propulsion system used liquid oxygen and gasoline, delivering roughly 350 kgf of thrust for a brief burst lasting about ten seconds. On June 11 1929, the RAK 1 performed a successful 3.5‑kilometre flight from Stuttgart to the nearby forest, reaching an altitude of 200 meters and demonstrating controlled rocket thrust for the first time in aviation history. Although the flight was short, the experiment proved that rockets could be used for aircraft propulsion, directly influencing later experimental designs such as the Heinkel He 176 and the early German missile programs. The Opel RAK 1 therefore occupies a unique place as the world’s first operational rocket‑driven aircraft and a milestone in the transition from propeller to jet‑based flight.