Siemetzki ASRO 4 (c/n 1, no registration) experimental rotorcraft, exhibited at Hubschraubermuseum Bückeburg (Bückeburg Helicopter Museum), June 2023.
The story of amateur-built ASRO rotorcraft begins on 4th September 1930. On that day, Alfons Siemetzki was born in Rössel, a small town in the then Ostpreussen (East Prussia) province of Germany. Although, from his early years, Siemetzki was fascinated with flying machines, the difficult time of the World War II did not allow the young man to pursue his passion for aviation.
After the war, a part of the former East Prussia province became a part of Poland. In 1946, Siemetzki, just like most of his countrymen from that area, moved to Germany. However, he returned to his hometown, now named Reszel, just after one year and then, since the late 1960s, Siemetzki´s life was split between two cities – the place he was born and Kirchdorf a.d. Iller in Baden-Württemberg, where he settled.
In Germany, Siemetzki studied mechanics and in 1954 became a licensed mechanic engineer. During his university years, he learned to fly gliders.
One of Alfons Siemetzki´s ideas was to create ´an affordable helicopter´, a simple and not expensive rotorcraft made of commonly existing on the market, serial manufactured mechanical parts and, therefore, available for everyone.
His works on models and prototypes led to development of ASRO 3 rotorcraft. It was an open-frame, small experimental helicopter powered by BMW motorcycle engine that successfully performed its first flight in October of 1959.
In the further stage of his development, Siemetzki equipped the rotorcraft with BMW Model 6002 turboshaft engine. The upgraded helicopter, known as ASRO 3-T, flew for the first time on 29th December 1961.
The next rotorcraft designed by Siemetzki was already featuring a fully enclosed fuselage. It was designated ASRO 4 and completed its maiden flight on 22nd January 1965.
The ASRO 4 helicopter was powered by BMW 6012 turboshaft engine (later known as MAN MTU 6012), generating about 100 hp – the same as the one used in the Dornier Do 32, one of the first rotorcraft developed in Germany after the war. The Siemetzki´s helicopter was built in classic configuration, with centrally mounted engine that powered three-blade main and two-blade tail rotors. The ASRO 4 was equipped with skid landing gear and could carry two people. Its estimated range was about 200 km and top speed up to 160 kph.
Regrettably, after a few evaluation flights, Siemetzki abandoned his idea of making the affordable helicopter. The ASRO 4 was never registered nor received any certification.
Interesting fact is that in designation of his rotorcraft, Siemetzki used both his initials and name of the place he was born. The ASRO abbreviation stood for Alfons Siemetzki Rössel Ostpreussen.
The only example of ASRO 4 helicopter is now part of rotorcraft exhibition at Hubschraubermuseum Bückeburg, the biggest helicopter museum in Europe (more information about the museum and its collection can be found in our article from August of 2023 – An incredible journey through rotorcraft history, from an aerial screw to the Mars Helicopter – Bückeburg Helicopter Museum).
In 2012, the German engineer became an honorary citizen of Reszel.
Alfons Siemetzki died on 7th April 2019, at the age of eighty-eight.
