While Ignor Sikorsky, the father of helicopters due to his small little system, the tail rotor. The man who is credited with creating the Intermeshing Rotor System is a Mr Anton Flettner.
Before we learn about Mr Flettner what’s Intermeshing Rotors?
The Intermeshing Rotor System is a set of two rotors turning in opposite directions, with each rotor mast mounted with a slight angle to the other, in a transversely symmetrical manner, so that the blades intermesh without colliding. The arrangement allows the helicopter to function without a tail rotor. Currently the HH-43 Huskie (One owned by Kaman and one in Oregon both air worthy), and the K-Max 1200 use Intermeshing Rotor Systems.
As Rotex flies their third Kmax to Switzerland let’s look at the history of where these incredible designs came from! We can trace the history back to Anton Flettner. Born in Eddersheim in 1885. Mr Flettner made important contributions to airplane, helicopter, vessel, and automobile designs. Anton served the German Military in World War One developing remote controls for air, water, and land vehicles. While working for Ferdinand Von Zeppelin Anton developed pilotless aircraft projects. At the age of 29 Anton presented his first invention, a steerable torpedo, to the Kriegsmarine (German Navy). However at the time the Kriegsmarine did not think it was technically feasible but in 1918 his ideas were wired to developing Air to Surface missiles. Another one of his many projects is the servo tab for vessels which would later develop into the trim tab for aircraft!
After World War One he was named Managing Director of the Institute for Aero and Hydro Dynamics in Amsterdam. During this time in the 1920s he developed the famous Flettner rotary ventilator which was widely used on buses, vans, boats, railroad cars, campervans, and trucks to assist cooling without the use of energy. These are still being made in England. Anton worked with scientist Albert Betz, Jacob Ackeret, Ludwig Prandtl, and Albert Einstein to design a ship using the Magnus effect. in 1926 Anton began switching his focus to aviation and finding his own company. The the Anton Flettner Aircraft Corporation in Berlin. His goal was to replace wings with the Flettner-rotor as a wing replacement. With his company Anton resigned from his position as Managing Director of the Institute for Aero and Hydro Dynamic. In 1935 Anton built a German night reconnaissance and anti-submarine gyroplane , the Flettner FI 184
The aircraft went on its first test flight, while in flight the aircraft caught on fire crashing thus ending the program.
In 1938, Anton with the help of Kurt Hogenemser, a German Aerospace engineer, would change the world with the Flettner FI 265. The Intermeshing Rotor System, or Flettner double rotor, addressed the problem of torque compensation as the first helicopter with counter-rotating rotor. Thus elimiting the need for a tail rotor.
The German navy supported this idea, the fact this machine could hover, and safely autorotate made it at the time the safest helicopter to fly. Six were built for the Germans.
As the World again entered World War Two, Anton would head the Flettner Flugzeubau. His new company specialized in making helicopters for the Luftwaffe. His helicopter inventions were financed from wealth acquired from his ventilator business. Though during this time Anton built helicopters for the Germans Navy, one issue was his wife, Lydia Flettner was Jewish. He held a personal relationship with the head of gestapo, Heinrich Himmler. Due to this connection the Himmler ordered his men to escort Anton and his family to Switzerland and made sure they were kept safe during World War Two. With Antons success of the FI 265, and being safe in Switzerland, he continued to build helicopters for the Germans. His second machine the FI 282 was built. Anton and Kurt insisted to the Germans that they would build the gears for the intermeshing rotors since it was so complicated to build.
The FI282 had amazing handling in bad weather, could safely landed if needed too.Because of its ability to hover and transport things from Shore to Ship, the FI282 saw service in World War Two near Rangsdorf Germany. In 1945 the FI282s would spot artillery targets and other for the Germans. Initally the Germans order 1,000 of the FI 282s but due to Allied bombing of the BMW in Muinch factory only 24 were ever built. There are only three that exist to this day. The FI282 also holds the title of being the world’s first series production helicopter.
After World War Two Anton and his family was brought to the United States as a part of OperationA Paperclip. Anton again started Flettner Aircraft Corporation, which developed helicopters for the U.S. military.Though his new company was not commercially successful, the US Army Air Force was interested in his helicopters and work. For his 14 years in the United States he worked for the Army, Air Force and Navy testing different helicopters. Anton would later become the head designer of Kaman Aircraft.
Because of his technology advancement Albert Einstein praised Anton’s work as “having great practical importance”.
Anton passed away in New York City on December 29th 1961. His partner, Kurt, passed away many years later on April 7th 2001. Both members were introduced to the American Helicopter Society. Antons birthplace home and tomb are national historic protected monuments in Germany.