[1] They were aware of the high-wing monoplane gliders that had been under development by Friedrich Harth, assisted by the teenage Willy Messerschmitt, since before 1915.

Two pairs of steel tube struts, attached to the top and bottom of the rear upright, spread out into Vs to support the rectangular plan tailplane.

Each leading edge was linked by a short forward extension of the control column by a vertical, outward leaning pushrod providing rotations of up to ±10°.

A grand prize for the greatest flight duration lasting more than 5 minutes with a specified maximum altitude loss was not awarded.

Nonetheless, Koller's total time of 31.6 minutes was made in only 25 flights and his average duration (76 seconds) was more than double that of the winner.

[2] At the next Rhön there were fifty-three entrants, ten of which had wings with adjustable incidence angles, including a Harth-Messerschmitt monoplane and the F.V.D.

The winner of the valuable Great Rhön Sailing Prize, the Hannover Vampyr which flew for over three hours, was not one of the ten.