The People's Helicopter Project @museum.de

Whenever Josef Maier was at Lake Constance, he met up with his brother Max and his friend Emil Mattes. One day, the factory owner Josef Wagner was also at the meeting and mentioned a manufacturing defect that had occurred at his firm, which manufactured paint-spraying guns. Because of this defect, a large consignment of faulty paint spraying guns had been returned from the US.

On the paper tablecloth of the restaurant where they’d met, Josef Maier sketched out a few drawings outlining a technical solution to these problems. Maier refused to accept any payment for his ideas by way of thanks.

And that launched the partnership between Josef Maier and Josef Wagner, united in their enthusiasm for aviation.

In Josef Wagner, Josef Maier found the perfect partner for his idea of a multifunctional "people's helicopter". Josef Wagner himself had long been obsessed with a vision of a "car" that could take to the skies as a helicopter.

Both now experimented with a engine that could power the blades on the rotor mast directly. The rotor blades were to rotate in opposite directions, eliminating the need for a tail motor. The goal was to make flying simpler, so that that even a layperson could learn the skill in a relatively short space of time.

From 1956 to 1958, Maier worked on developing a helicopter engine at his factory in France. It actually had to be smuggled across the border to Fischbach in pieces – secretly bypassing customs.

The first engine, a three-cylinder radial engine, proved to be underpowered. The second attempt, with a four-cylinder radial engine, resulted in a crash on the factory floor. Wagner was "not amused". After a third attempt also failed, Wagner seconded some graduate engineers from his factory to assist Maier. But Maier was self-taught, and the collaboration with the engineers was not successful. It ended in 1962.

After a lengthy development period, the ROTOCARS system was devised. A bare-bones design with a torque-free and gearless drive and no clutch brought the helicopter’s own weight down to just 50 per cent of a conventional helicopter’s weight. However, the payload exceeded 55 per cent. The helicopter essentially consisted of three elements: engine, passenger cell and rotors with control elements.

As early as 1961, the Südkurier newspaper reported on a Rotocar that was supposedly going to cost little more than a car.

But these lofty dreams came to nothing. All the engine variants lacked sufficient power. Funding failed to materialise, as did investors willing to support ongoing development.

It was only when an American Franklin engine was used that three airworthy prototypes of the Sky-Trac type could be exhibited at the Hanover Air Show in 1966.

The firm of Wagner Helicopter-Technic was granted type certification in Germany in 1969. Certification in the US followed in 1972. Wagner had set up a new firm called Helicopter Technic München (HTM) in 1971 to handle the manufacturing. There were plans to build approximately 400 units by 1977.

But the delay and technical glitches caused disquiet among clients and financiers, and they backed out.

By 1974, HTM was inevitably heading into bankruptcy. However, one helicopter that emerged from this collaboration between Maier and Wagner is still on show today at the helicopter museum in Bückeburg, Lower Saxony.