The response of most carmakers to plans for a rocket-powered car would have been frosty. But Fritz von Opel was fascinated by the theories of Max Valier, inventor and author of The Advance Into Space, and in 1927 agreed to help him create just such a vehicle. The Opel company's research department was assisted by rocket scientist Wilhelm Sander. They produced the "Rakentenwagen" (or RAK 1), equipped with solid fuel rockets. At Opel's Russelshiem test track in April 1928, the car reached 62mph (100kph) in just eight seconds. The car was then radically redesigned as the RAK 2, with huge wings on either side to counteract any tendency to leave the ground. It was equipped with 24 cluster-powder rockets, calculated to give 13,228lb (6,000kg) of thrust. At Berlin's Avus race track on May 23, the crowd went wild when Opel reached 148mph (238kph). "Rocket Fritz" made headline news worldwide, amid speculation that the technology could transform world travel. The publicity worked wonders. It probably sweetened General Motors' buy-out of the Opel family's carmaking interests in 1928-they received $66.7 million.