Walter Rieseler (1890–1937) was a German aircraft developer. Once he had gained his pilot’s licence, he opened a flying school at Berlin-Johannisthal airfield and trained other pilots. Later on, he developed his own planes, including the Rieseler Parasol R III sport aircraft, which was the first private and sport aircraft to be built under licence. Rieseler was also dedicated to designing helicopters. His work in this field included developing the R1 helicopter for the German Department of Aviation, which was the first helicopter with rigid, contra-rotating coaxial rotors.