The First Retractable Undercarriage

The fs18 arose from experience gained from the Rhön Gliding Competition. It was designed to be able to thermal tightly with as little sink rate as possible. Six months were available for the construction of the plane.

The fs18 has a high-wing configuration. Its wings are square in the innerside with trapezoid outer panels. There’s a kink at the 4 m span, where the two-piece aileron begins. The wings are also equipped with flaps, with a depth of 30%. They are attached perpendicularly to the fuselage to reduce interference drag at the wing root as much as possible.

The fs18 was the first sailplane to receive a retractable undercarriage. The wheel is in its retracted configuration fully covered inside the fuselage contour, with the wheel well being covered by the undercarriage doors. As with the F.1 and fs16, the fuselage behind the wing is raised upwards.

On the 7th December 1938, the fs18 was destroyed in a plane crash which killed its pilot, Ernst Scheible.


First flight21 July 1938
Method of constructionWood
Wingspan18 m
Wing area18 m²
Aspect ratio18
ProfileNACA 23012
thickened to 23018
between 1,5 – 0m
Dihedral angle
Wing sweep
Aileron area4,9 m²
Flap area3,5 m²
Elevator area1,425 m²
Rudder area1,0 m²
Length8,7 m
Height1,75 m
Empty weight215 kg
MTOW315 kg
Glide ratio26,9
Best glide speed78 km/h
Min. sink speed53 km/h
Landing speed37 km/h
Ultimate load factor10g