Kratzner Plank
The construction was foam and glass D cell straight D cell wing. The nice feature is it allows the use of ailerons with differential throw as the lever arm from the ailerons to the CG is too short to give much pitch change - so no need for spadds, spoilerons, tip rudders or other complicated devices.

The 1982 Kratzner Plank was for advanced pilots.
proto unique
Wing area: 17 m²
Wing span: 12.78 m
Aspect ratio: 9.6
Hang glider weight: 59 kg
Minimum speed: 29 km/h
Maximum speed: 100 km/h
Max glide ratio (L/H): 16
Minimum sink rate: 0.78 m/s
Nose angle: 180°