B.they are impressive, these sublime-looking gliders with mighty spans beyond 20 meters. They are the so-called open class gliders, a kind of Formula 1 of the skies, in which there are no upper limits in terms of wingspan. The giants, hovering majestically between heaven and earth, became famous through the plane of Hans-Werner Grosse, who died in February – the Eta, which had extremely broad shoulders. The 30.90 meter wingspan of this tall ship, which took off on its maiden flight in 2000, was a record. There were only three machines of this type, which impressed with one characteristic above all: the sliding ability. The Eta showed off with a glide ratio of 70, which means: From a height of one kilometer it came 70 kilometers without having to climb in between. For comparison: an Airbus A340 can travel 16 kilometers without an engine thrust.
New signals are now being sent from Poppenhausen at the foot of the Wasserkuppe. The world’s oldest glider manufacturer is located in the wide hilly landscape of the Rhön: Alexander Schleicher. A machine is currently being developed there that will cause a stir with a span of 20 meters, the minimum in the open class: the AS 35 Mi. The last two letters stand for the engine and the injection system. Because even gliders can have engines. The AS 35 Mi will be capable of self-starting thanks to a 56 hp Wankel engine. If necessary, the unit and propeller fold out of the fuselage of the machine and, depending on the amount of water ballast, pull the aircraft, which can weigh up to 730 kilograms, into the sky. Or they enable you to return to your home airfield should the pilot run out of thermals.
Alexander Schleicher is currently testing the new aircraft with a new computer model and a CFD (Computional Fluid Dynamics) simulation. “These calculation models are very close to reality,” says Patrick Wenzeck, the head of marketing at the traditional Hessian company, which will be 95 years old next year. The company’s founder, Alexander Schleicher, built his first aircraft in 1927. The name of the device with which Schleicher, who died in 1968, won the Rhön gliding competition: “Get the devil”. The prize money formed the basis for the purchase of the first workshop space. Today there are 115 employees at Alexander Schleicher. Five people are responsible for developing new projects like the AS 35 Mi. Whether a new aircraft can do what the engineers have calculated is tested practically on the doorstep. Because Schleicher has its own airfield, including a tow plane, behind the production halls.
Wingspan is the magic formula that enables gliders to glide far. But in everyday use, the white giants of the air have disadvantages. In the warm, rising air they have to go further in circles called “cranks”, while gliding they are slower than the competition, which is equipped with shorter wings, whose wings offer far less resistance to the air flowing past than those of an Eta, for example. This is particularly advantageous in difficult thermal conditions, as the greater range when gliding gives the pilot more chances of finding the next updraft. Under normal conditions, however, modern gliders with a smaller wingspan are superior to the so-called “long-eared”.