Heinz Keller has died

Heinz Keller, born in 1929, first completed an apprenticeship at Hanauer Vakuumschmelze after graduating from high school; he then returned to work for the company that had trained him after earning a degree in physics from Goethe University in Frankfurt. There, Keller, a graduate in physics, began working early on with alloys of the rare-earth metals cobalt and samarium and quickly recognized the potential of these—at the time—novel magnetic materials for the construction of high-torque electric motors. The inspiration to try building a motor himself came from his hobby of model racing boats, which he pursued in his free time at the Fulda Model Boat Club.

Very soon after—it was probably 1978—electric model airplane enthusiasts also discovered the significance of this innovation. Until then, they had mostly struggled to gain altitude using Japanese Mabuchi motors, which were designed for power tools. The Keller motors brought a whole new dynamic to the electric aviation scene, which had previously often been ridiculed for its lack of power. Soon, it was impossible to win a competition without a Keller motor. Demand exploded, so that on the 25th anniversary of his employment at Vakuumschmelze, Heinz Keller resigned from his secure position and founded his own motor company. The now-legendary “Keller 50/24” was followed by numerous motor models for various applications and power classes. Yet his business acumen always lagged behind that of the designer and tinker. Heinz Keller did not concern himself with sales promotion in the modern sense; instead, he preferred to support young competitors—

commercial pilots. Getting a Keller motor wasn’t always easy; the service was more like a support program for competitors.

In 1989, Heinz Keller sold his engine manufacturing business to Robbe and, throughout the 1990s, pursued electric flight solely as a hobby. He turned his research attention to the nickel-cadmium cells that were common at the time. With great dedication, he collected measurement data and published the findings he had gathered in a technical book. Even then—

he continued to attend electric flight events time and again, always in his unmistakable outfit. He was often seen as a fellow citizen who was highly critical of the spirit of the times.

Although Heinz Keller had increasingly withdrawn into private life in his final years for health reasons, his name and his associated contributions to electric flight will remain indelibly etched in the memory of future generations. ■

*Ludwig Retzbach*