The two-seater is an impressive 101 years old – and 100 percent roadworthy. Well maintained anyway. If you want to get ahead with it as a driver in the 21st century, you have to scale back your comfort standards a little. Wilfried Senger pulls the choke while his son Ansgar operates the hand crank. The Opel 4/16 HP comes to life. “The accelerator pedal is in the middle. And when clutching, you always have to double-clutch,” explains Senger Sr.
Twelve rockets instead of four cylinders
Is there any driving pleasure there? “And whether!” But there was a time when this very vehicle was not powered by four cylinders, but rather with the help of rockets. The Senger family from Rheinhessen owns a particularly valuable relic: “This car was once the legendary RAK 1 rocket car,” says Wilfried Senger. How did the vehicle, long considered missing, come into his possession? The 86-year-old tells the exciting, eventful history of the Opel original.
The current owners Wilfried (left) and Ansgar Senger tell the story of the former prototype, which was converted into a rocket car and later rediscovered in a garage.
On April 11, 1928, a test drive with the RAK 1 took place on the Opel test track in the presence of press representatives. Friedrich Sander (left at the rear) is personally responsible for loading the rockets.
With Kurt Volkhart at the wheel, the RAK 1 reaches 100 km/h within eight seconds.
The basis is an Opel 4/12 HP. Around 40 kilograms of explosives are mounted in the rear.
In 1930, Josef Becker bought the vehicle, which had since been converted into a racing car.
“…the car shot away with me, the track became a narrow line, the acceleration became the highest pleasure and jubilant liberation.”
– Kurt Volkhart about the journey in the RAK 1 –
The story begins in 1923 in the Opel testing department. The employees built a racing car based on the 4/16 hp pre-series of the tree frog, which achieved several victories by 1926. At the wheel: Fritz from Opel. When the company founder’s grandson meets the pilot Max Valier, with whom he shares his enthusiasm for young rocket technology, they decide to build a rocket car. To quickly implement a “rocket engine,” they bring Friedrich Sander on board, whose company produces solid-fuel rockets for signaling purposes.
The RAK 1 is transformed from a racing car
They convert Fritz von Opel’s racing car into the “T35 test car”, the engine comes out, instead twelve rockets decorate the rear, which are activated by a pedal in the footwell. The car, which was given the name RAK 1, demonstrated its potential on April 11, 1928 during a drive on the Opel test track in Rüsselsheim: Although only seven of the twelve installed rockets ignited, the car accelerated within eight seconds with Kurt Volkhart at the wheel to 100 km/h.
The successful attempt made it onto the front pages of many German daily newspapers. “The previous attempts have been far more successful than we, Max Valier and I, could have imagined,” says Fritz von Opel in a press release and announces another demonstration at the AVUS in Berlin in a newly built vehicle. On May 28, 1928, Fritz von Opel personally sat behind the wheel of the RAK 2 with 24 powder rockets in the back and set a celebrated new distance speed record of 238 km/h. The rocket age has arrived.
Sleeping Beauty sleeps in the coach house
And the RAK 1? It has had its day and is being dismantled. So out with the rockets and in with the four-cylinder engine. What’s left is a normal sports car. Irmgard von Opel, also a granddaughter of the company founder, drove it for two years, then in 1930 she sold it to Josef Becker, the uncle of Wilfried Senger’s wife Roswitha. The new owner only drove the car briefly and parked it in a shelter in 1933. The coach house becomes overgrown, the first rocket car is forgotten as it disappears under leaves, twigs and bushes. Which is perhaps even fortunate for the sports car, as it remained undetected even during the looting in the post-war years.
It wasn’t until 1986, when Josef Becker had already died, that his niece Roswitha and her husband Wilfried Senger came across the forgotten automobile. “It was completely rusted through, but still complete,” remembers Wilfried Senger, heir to the Senger car dealership, which was founded in 1933. And the trained car mechanic gets to work.
Essential modifications
He takes the car apart and brings every single part back to a high shine – the project lasts over 14 years. Because: He places the highest demands on his work. The Opel classic car should remain as close to the original as possible. He only allows himself modernizations “where they are essential”. For example, to get the engine cooling under control, which repeatedly causes problems. And a turn signal is a must these days to be allowed on public roads.
“To be honest, the car’s eventful past wasn’t and isn’t that important to me – I love it the way it is now.”
– Wilfried Senger –
The Sengers are expected to present the Opel 4/16 PS to the public at the Classic Gala in Schwetzingen at the end of August.
In the 1920s, the eye was the official Opel emblem. In 1935 it was replaced by a stylized Zeppelin.
VR is the historical vehicle registration number of the province of Rheinhessen in the German Empire.
The vehicle was painted beige and red when it was used as a racing car.
Paint residues in UV-protected areas, such as under decorative strips, served as a reference.
In 1999, Wilfried Senger presented his work to the public for the first time: in Rüsselsheim, as part of the supporting program for the 100th anniversary of Opel automobile production. Although the car is recognized, admired and celebrated as a unique prototype from the tree frog era, its glorious past as the RAK 1 is only revealed a few years later. It was Friedrich Rappsilber, vehicle appraiser and type representative for Alt-Opel-IG, who managed to establish the identity beyond doubt in 2006.
Appraiser reveals identity
Based on documents, statements from contemporary witnesses and certain details that are still visible on the vehicle today, such as the holes for the air baffles in the body frame, Rappsilber comes to the conclusion in his report that “the motor vehicle to be assessed is the first vehicle for Tests with rocket propulsion were used – called RAK1 in the specialist press.
Since the other rocket creations from Rüsselsheim – RAK 2, RAK motorcycle and RAK aircraft – only exist as replicas today, Wilfried Senger is in possession of the last original. “To be honest, the car’s eventful past wasn’t and isn’t that important to me – I love it the way it is now,” he says, taking a seat behind the wheel of his two-seater.
Guest appearance in the anniversary year
Like last year, Ansgar Senger will probably present the car at the Classic Gala in Schwetzingen, which is scheduled for August 30th to September 1st, 2024. “After all, the focus this year is on the 125th anniversary of Opel automobile construction,” says the 59-year-old junior happily. A worthy setting to present the last witness from Opel’s rocket days to the public.
March 2024
Text: Eric Scherer, photos: Alexander Heimann, Opel Archive, private