The Bäumer B II "Sausewind" was a light sports tandem two-seat, open cockpit, wooden cantilever monoplane. It was built by German aviation company Bäumer Aero GmbH, based at Hamburg Airport.
It was the first aircraft made in Germany to be designed for aerodynamic performance.[1]
The development was triggered when the BZ am Mittag announced the "B.Z. Preis der Lüfte (BZ Prize of the Skies)" as part of the 1925 Deutschland-Rundflug (The Round Germany Flight) [2] which offered prize money of 100,000 Reichsmarks for the winner.
The brothers, Siegfried and Walter Günter, designed the B II at Bäumer Aero GmbH. The "Sausewind" was the first aircraft to make use of a elliptical wing and tail units, which offered aerodynamic advantages over the rectangular wings that were common at the time. To reduce air resistance all control cables and control levers were installed internally. The undercarriage used split axles to reduce drag compared with a continuous axle.
On May 31, 1925, the B II took off from Berlin-Tempelhof for The Round Germany Flight. The flight time (including several emergency landings) for the distance of 5,242 kilometers was 91 hours and 12 minutes over five 2-day stages. The Sausewind took second place in Group B for aircraft with a maximum of 80 HP. It received a prize of 15,000 Reichsmarks.
At the Otto Lilienthal Competition from June 15 to July 23, 1925, the B II won the highest speed at 100 m altitude (183.5 km/h), maximum altitude (4770 m) and best climb rate (2.11 m/s).
The B II “Sausewind” was lost in a crash landing on September 19, 1925.