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EWALD ROHLFS TOOK THE FW 61 TO AN ALTITUDE OF JUST OVER 1,300 FEET AND SWITCHED OFF THE THE ENGINE. ROLFS SUBSEQUENTLY MADE THE FIRST SUCCESSFUL HELICOPTER AUTOROTIONAL LANDING.


politically unpopular. After losing


his status as the Technical Director at Focke-Wulf, Focke assembled a group of engineers to begin work on a helicopter. The group eventually developed a three horsepower, elec- tric model which was used to refine rotor head designs. Subsequently, a small scale free flying model of the entire helicopter underwent exten- sive wind tunnel testing. Construction on the full scale heli- copter began in March of 1935. To counter torque effects, the


Fw 61 used two rotor heads turning in opposite directions.


The rotor ROTORCRAFTPROFESSIONAL


heads were located on steel outrig- gers extending from the fuselage. Each rotor head had three fully articulated,


fabric-covered rotor


blades made of a steel spar and ply- wood. To save development time, a


Focke-Wulf Fw 44 Stieglitz fixed- wing fuselage was used for the body of the helicopter. The Fw 44 was a popular two cockpit training biplane.


A 160 horsepower


Siemens-Halske Sh 14E radial engine powered the rotors through a system of gears and shafts. A small propeller was put in the front


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of the aircraft which gave it the appearance of an Autogyro. However, the propeller provided no thrust and was simply used as a fan to cool the engine behind it. The first Fw 61, designated as Fw 61 V1 and registered as D- EBVU, was completed sometime late in 1935. The building of a sec- ond prototype known as Fw 61 V2 began in January of 1936 and fin- ished in early 1937.


Although


Heinrich Focke had separated from Focke-Wulf, he was still using the Focke-Wulf wind tunnel and the company’s manufacturing facilities.


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