The H.III was designed to compete at the 1938 Rhön Gliding Competitions at the Wasserkuppe and two aircraft were available at the start of the competition, to be flown by Heinz Scheidhauer and Werner Blech. As the competition progressed the two H.IIIs were achieving reasonable results with Blech leading over Scheidhauer. Near the end of the competition the weather deteriorated with cumulonimbus clouds and rain showers. Blech recognised that he could win the competition outright with a high-altitude flight in one of the clouds.