01/31/2010. Remarks by Kees Kort: "Designed by Gabriel Letsch the 20 E.I, also referred to as the Kavallerie-Eindecker (Cavalry Monoplane), was produced in 1913. The 161.46 sq.ft (15 sq.m) wing measured only 29 ft 6.3 in, and powered by an 150 Argus engine, it achieved a speed of 84 mph (135 kmh)."