In early 1928, Fritz von Opel teamed with rocketry promoter Max Valier and pyrotechnics maker Friedrich Wilhelm Sander to test solid-fuel rockets as practical propulsion. Their plan used dramatic public demonstrations to prove control and power, moving step-by-step from ground vehicles to aircraft.
Opel scheduled an initial RAK.1 rocket-car trial at the company’s facilities in Rüsselsheim to begin with cautious, low-speed testing. Kurt C. Volkhart served as the driver for the earliest runs as the team learned how to ignite and sequence the rockets safely.
A widely reported RAK.1 demonstration in Rüsselsheim showed the car accelerating rapidly to around 100 km/h, even though not all rockets ignited reliably. The event helped convince audiences that rocket thrust could be managed on a vehicle, not just in theory.
Fritz von Opel drove the Opel RAK.2 on Berlin’s AVUS course, using 24 solid-fuel rockets and small stabilizing winglets. The run reached about 238 km/h and became the program’s best-known public proof that very high speeds were possible with rockets.
To move from ground tests toward aviation, the team fitted rockets to Alexander Lippisch’s canard glider, the Lippisch Ente. Test pilot Fritz Stamer flew it under rocket power at the Wasserkuppe on June 11, marking a landmark early step toward rocket-propelled flight.
Later testing of the Ente ended when a rocket failed catastrophically and the aircraft caught fire. Stamer was able to land, but the glider was effectively destroyed, pushing the group to pursue a new airframe designed specifically for rocket experiments.
The program expanded to rail-based tests with the unmanned RAK.3, a rocket vehicle designed to run on tracks. On a straight stretch near Hanover/Celle, it reached roughly 254 km/h (about 157.5 mph), showing how rockets could deliver sustained high speed in a guided run.
After its headline-grabbing run, the RAK.3 program ended abruptly when the vehicle jumped the track on another attempt and was wrecked. The accident highlighted a recurring problem for the demonstrations: controlling ignition, thrust, and stability at extreme speeds.
A follow-on rocket vehicle, known as RAK.4, was destroyed when rockets exploded during a test run. The blast became one of the most vivid reminders that black-powder rockets could be powerful but also unpredictable, especially when used in large clusters.
After the Ente’s loss, Fritz von Opel commissioned aircraft designer Julius Hatry to build a purpose-made rocket aircraft. At Frankfurt’s Rebstock airfield, von Opel flew the Opel RAK.1 in front of a large crowd, demonstrating controlled rocket-powered flight over a short distance.
Despite the successful 1929 airplane demonstration, the intensive Opel-backed campaign did not continue as a sustained development program. The work remained an important proof-of-concept for rocket propulsion, but the highly public, high-risk test style proved difficult to carry forward.
Max Valier, one of the key public advocates and organizers behind the Opel-RAK demonstrations, was killed in Berlin during a later rocket-engine test. His death underscored the danger of early rocketry and marked a sobering endpoint to the most famous public “rocket vehicle” era of 1928–1929.
Opel RAK Rocket Propelled Car and Glider Demonstrations (1928–1929)