Henrich Focke

Germany

 

In 1910, Henrich Focke began to study at the Technical University of Hanover, where he became friends with Georg Wulf a year later.

When designing and building the A IV, a wing was modeled after the shape of the Zanonia seed, for the purpose of stability and safety, a main focus of Focke’s designs throughout his life.

In 1914, Focke and Wulf both reported for military service and both deferred, Focke due to heart problems, and Georg because of vision problems. Both were eventually drafted and Focke ended up in an infantry regiment. After serving on the Eastern front, he was transferred to the Imperial German Army Air Service where he became a teacher at the DVL in Berlin, while Wulf, who had a natural talent for flying, made it into a flying school.

After WWI, Focke took up his studies, taking supplementary courses in aeromechanics, design, and operation of aircraft, and graduated in 1920 as Dipl.-Ing. (roughly equivalent to a master’s degree) with distinction. His first job was with the Francke Company of Bremen as a designer of water-gas systems, where he managed to also find a position for Georg Wulf. At the same time, in 1914, both continued work on the unfinished A VI in the basement of his father’s Focke-Museum, which became the A VII. The A VII flew in 1922 and was certified.

In 1923, with Wulf and Dr. Werner Naumann, Focke co-founded Focke-Wulf Flugzeugbau GmbH. At the time, the Treaty of Versailles only allowed small aircraft with weak engines to be built in Germany after WW I.

In 1924, the first contract was for designing a 4-seater, which became the Focke-Wulf A 16. It was successful and 22 were sold. During design, model tests were performed at the AVA Göttingen under Ludwig Prandtl to make proof of the estimated performance.

In 1927, Wulf died while test flying the Focke-Wulf F 19 “Ente” canard monoplane, and in 1929, a large fire destroyed the manufacturing plant. Despite these setbacks, a series of successful aircraft followed, all derivatives building on the progress of the former.

Inflation in Germany caused an economic crisis which affected their industry and they lost government contracts. This forced a merge with the Albatros aircraft manufacturing plant in 1930, and thus a partial loss of control of the Focke-Wulf company. However, Focke’s success was honored by the Senate of Bremen with a Professorship in 1931. During that time, in secrecy (the Treaty of Versaille was still in effect), the German aircraft manufacturing plants were already equipped for mass production of aircraft.

Political influence grew further when Focke was forced to hire engineer and pilot Kurt Tank at the demand of the Reichs Aeronautics Ministry. When the Nazis took over the government in 1933, Tank was a staunch supporter of the ministry and was made to replace Focke in his own company the same year. However, Focke had friends on his board which gave him a fixed salary as an employee. There he would further make use of the wind tunnel that he had built in the 1930s, and got a building for his further studies and experiments in Hemelingen, near Bremen, and had some of his former staff, craftsmen and workshop machines.

Focke-Wulf constructed Juan de la Cierva's C.19 and C.30 Autogiros under license from 1930 until 1937. Focke was not satisfied with the remaining need for take-off speed and discussed the further development of a true helicopter with Cierva, who judged that as too complicated. Focke, however, was inspired by this complication and began, supported by the motor manufacturer Siemens, to design his first helicopter in 1930. Model tests in his wind tunnel supported and extended the scarcely accepted theory of vertical take-off, and in 1932, he proposed a helicopter project to the ministry with drawings and calculations, which was granted that same year. The design guidelines were described by Focke as six major items:

1. Safe landing in case of engine failure.
2. Controllability and Stability.
3. General safety of operation.
4. simplicity of control
5. Acceptable performances.
6. Maintenance of no more difficulty than in airplanes.

A free-flight model followed (that was more broken than intact during its life) and after many tests in his wind tunnel as well as in that of the AVA Göttingen, the world's first practical helicopter, the Focke-Wulf Fw 61, took shape with first tethered flights in late 1935 and which first flew on June 26, 1936 with pilot Rohlfs on the controls, and exactly one year later he broke all existing helicopter world records with it: range of 80 km (1 km before), altitude 2439 m (158 m before), and had demonstrated autorotation landings.

In Spring 1937 Focke canceled his contract with the Focke-Wulf company but remained a member of the supervisory board. Ernst Udet was Focke’s friend with a vision in the Air Ministry, who had been impressed by the Fw 61 helicopter and who suggested that Focke establish a new company dedicated to helicopter development and issued him with a contract for an improved design capable of carrying a 1,500 lb (700 kg) payload in 1938. The vehicle was initially ordered for the Lufthansa and designated Fa 266. The payload requirement led to a total weight estimate of five times the payload, an 800 HP engine and two rotors of 12 m diameter each – a quantum step from the little Fw 61.

Focke established the Focke-Achgelis company on 27 April 1937 in partnership with pilot Gerd Achgelis and began development work in Hoyenkamp near Delmenhorst in 1938. A series of honors were given to Focke in that year: the golden Lilienthal Memorial Coin, a Dr. h.c. from the TH Hanover, and the title “Wehrwirtschaftsführer”, given to important industrial leaders from the Ministry of Economics with the goal of binding these companies to the military.

With the outbreak of WWII, the Fa 266 was converted for military use and renamed to Fa 223, which was equipped with a 1000 hp Bramo engine. The development was accompanied by many especially dynamic problems never experienced in the Fw 61, but on June 12, 1940, the first free flight took place. Then records were achieved in breathtaking speed: Oct. 15: hover with MTOM of 4300 kg (1596 kg payload), Oct. 22: max. speed: 113 mph (182 km/h), max. height: 7,100 m; climb rate 1,732 ft/min (8.8 m/s). 1941 an order for 100 Fa 223 Drache ("Dragon") helicopters was placed, but on June 1942 the manufacturing plant and all machines under construction were destroyed by a bombing raid, leading to relocation to Laupheim south of Ulm. Subsequent war models were primarily used for mountain troop transport, rescue, and crashed aircraft recovery. The helicopter had provision for a nose-mounted machine gun and could carry one or two bombs, but the Drache was never used for combat. Again, in July 1944 that location was destroyed by bombing. Relocation to Ochsenhausen near Biberach took place, and until the end of the war only about 20 vehicles could be built, despite a new order for a production rate of 400 vehicles/month in late 1944, and relocating the production to Berlin-Tempelhof, where in Spring 1945 the first Fa-233 was finished, when Russian troops were surrounding the city.

Focke-Achgelis also built the experimental Fa 225 using the fuselage of a DFS 230 glider and a rotor from a Fa 223. Another project was the Fa 330 submarine kite with a rotor, capable of being deployed by a submarine on short notice and then used as a towed spotter. It was stored in a watertight container on the deck of the U-boat and was used during the war. Production remained in Hoyenkamp because it could easily be carried into underground shelters during a raid. About 200 Fa-3300's were built from 1942 on. Focke also designed the Fa 224 (1939, training helicopter similar to Fa 61), Fa 269 (tiltrotor, never built), Fa 283 (jet gyrocopter, design only), Fa 284 (prototype of heavy transport helicopter), and the Fa 336 (prototype of a Fa 330 converted to a helicopter) during World War II.

A captured Fa 223 was flown to the UK for evaluation in September 1945, the first crossing of the Channel by a helicopter – 30 years after the famous flight of Luis Bleriot in his monoplane.

On Sept. 1, 1945, Focke and his team signed a contract with the French company SNCASE and assisted in the development of their SE-3000 passenger helicopter, which was based on the Focke-Achgelis Fa 223 "Drache" and which first flew in 1948. In parallel, the SE-3101 with a V-tail and two tail rotors at the tips of it – a Focke patent also seen on his later helicopter projects – was built, also flown first in 1948, which became the “grandfather” of the successful Alouette. The contract with SNCASE ended prematurely in Summer 1947 and Focke returned to Germany.

Focke returned to Bremen to work for the car manufacturer Borgward designing busses. The currency reform in 1948 caused a loss of all savings and with the remaining assets, he bought a property in Bremen and built his own home. In 1950, he worked as a bus designer with the North German Automobile Company (Norddeutsche Fahrzeugwerke) of Wilhelmshaven.

Spare time was filled with ideas on an aircraft convertible from a helicopter for take-off and landing to a fixed-wing for cruise. These led to his hiring by an industrialist in the Netherlands in 1951 and the “Convertiplane” or “Heliconair” named vehicle slowly took shape on the drawing board. Funding quickly seized, but in 1952, Focke and other members of his former design team were employed by Brazil's Centro Técnico Aeronáutica (CTA) in São Paulo, at the time the air force's technical center, to develop the "Convertiplano" (convertiplane), which drew heavily on Focke's wartime work on the Fa 269. Also recruited was Bussmann, a transmission specialist formerly of BMW.

While working at the CTA, Focke also developed the BF-1 Beija-Flor (hummingbird) two-seat light helicopter from 1955, which made its first flight at San Jose dos Campos on Jan. 22, 1959. The BF-1 was similar in design to the Cessna CH-1, with a 225 hp Continental E225 piston engine in the nose and the rotor mast running vertically between the front seats. An open structure tubular steel tail boom carried a pair of tail surfaces and two intermeshing tail rotors incorporating combined and differential pitch, while the main rotor had collective and lateral cyclic pitch control only. This helicopter incorporated dynamic stability by itself without any complex and expansive electric controller. The BF-2 was developed from this and first flew on Jan. 1, 1959 and performed an extended flight-testing campaign until it was damaged in an accident. The Beija-Flor was built in small series production until the 1970s.

The Heliconair on a test rig experienced a gearbox failure, but repair was denied by the manufacturer and the project was thus abandoned. 1954 Focke got an offer from the Technical University Stuttgart as Professor for aircraft technology and design and since then he spent the winter in Germany with teaching, while working during Summer in Brazil. However, the Administration of the University and its funding Ministry of Education permanently delayed his professorship, his permanent hiring, the promised setup of experimental facilities and left Focke frustrated, despite having liked very much teaching and working with young and interested students. In 1956 Borgward in Bremen, for whom Focke had worked some years before, approached him to enhance his car portfolio by a small “Volkshelicopter” to be designed by Focke and his team.

Focke happily accepted that offer, left the University in Stuttgart and returned permanently to Germany in 1956 to develop a three-seater helicopter named the "Kolibri" (hummingbird) at the Borgward company, with its first flight taking place in 1958 with pilot Rohlfs at the controls, who formerly also flew the FW 61. The Kolibri had similar features as the SE-3101 and the Beija-Flor in Brazil, with a V-tail and two tail rotors. A second prototype was finished 1960, but right before the test flights with pilots from the DFL could take place, Borgward went bankrupt and all activities on the Kolibri stopped instantly and Borgward was dissolved in 1961.

Focke for the fourth time lost his life’s work and, now at an age of 71, became a private consultant for the Deutsche Forschungsanstalt für Luft-und Raumfahrt (DFL) in Braunschweig, with Vereinigte Flugtechnische Werke (VFW) in Bremen and Rheinische Flugzeugwerke in Krefeld until 1965, when he retired. With some support of VFW Focke built his own lab in 1961 with a wind tunnel in Bremen (this wind tunnel was rediscovered in 1997 and is today the “Henrich Focke Wind-Tunnel” museum, which was awarded as “Vertical Flight Heritage Site” by the Vertical Flight society in 2019) in order to continue his aerodynamic experiments and investigations. During that time he was honored by the Franklin Institution in Philadelphia with the “Howard H. Potts Gold Medal”, handed over by the son of his friend Igor Sikorsky.

Focke was also awarded the Ludwig-Prandtl-Ring from the Deutsche Gesellschaft für Luft- und Raumfahrt (German Society for Aeronautics and Astronautics, DGLR) for "outstanding contributions in the field of aerospace engineering" in 1961. Focke died in Bremen on Feb. 25, 1979.

 

 

 

Milestones associated with Henrich Focke
June 26, 1936	First flight of a practical, controllable helicopter (Focke-Wulf Fw 61)
June 26, 1936	First flight of a lateral tandem rotor configuration (Focke-Wulf Fw 61)
May 10, 1937	First autorotational landing by a helicopter (Focke-Wulf Fw 61)
June 26, 1937	Focke Fw 61 completes breaking all existing helicopter world records
June 12, 1940	First flight of the Fa 223