|Based on the Pegasus FW-44|
|Brian R Baker|
|Much kit bashing involved!!|
Later, Cierva developed original designs and autogyros, while never
completely successful in a commercial sense, were used during the thirties
in small numbers. American producers of autogyros include Pitcairne and
Kellett. At least one Pitcairne, owned by the son of the designer, is
still flying today. Others are preserved in various places.
The transition from autogyro to pure helicopter, which provided an aircraft that could actually hover and make vertical takeoffs and landings, involved the efforts of the German Focke Wulf firm, and the designing genius of Heinrich Focke. In the early thirties, Focke Wulf contracted with the Cierva firm to build under license C.19 and C.30 autogyros. Over thirty were built, and based on the experience gained, Focke decided to try to build a true helicopter.
In 1935, Focke designed and built a prototype of an autogyro which competed in the Luftwaffe contest to develop a utility and liaison aircraft. The winner was the Fieseler Fi-156 Storch, and only one FW-186, which was essentially a FW-56 Stosser advanced trainer fuselage with a single rotor assembly and a modified tail and landing gear. This provides the basis for another kit conversion, but not here.
After the FW-186 project, Focke decided to concentrate on the helicopter. In true Germanic fashion, he took an engineering approach, and formulated basic requirements for his aircraft, which included controllability, reliability, simplicity of control, adequate performance including reasonable cruising speed, and ease of maintenance. With these factors in mind, he set about to develop a pure helicopter, and aircraft with the primary power geared directly to controllable rotor blades, which provided both lift and thrust.
After the concept was established, Focke test flew a scale model of the design, and in 1934, this model achieved an altitude of 59 feet, which was equal to the altitude record for previous manned unsuccessful experimental helicopters.
Focke selected the Focke Wulf FW-44 Stieglitz as the basis for his design. In fact, the prototypes were actually conversions of FW-44 fuselages, with wings and tail removed and new equipment installed. The configuration chosen was two rotors located on each side of the aircraft, far enough apart to avoid aerodynamic interference. This also solved the problem of rotor torque, which on single rotor helicopters required a tail rotor to achieve stability. A 160 hp. Siemens SH 14a radial engine was located in the nose to provide power for the rotors, and a small fan was mounted in the usually position for engine cooling only. The location of this fan was construed by many to be a means of thrust, and this argument t was used by Sikorsky supporters to claim that his VS-300, which flew four years later, was actually the first successful
helicopter. Not so! The FW-61 was the first successful helicopter.
The first FW-61 prototype, D-EBVU, made its first tethered flights in early 1936. On 26 June 1936, the aircraft made its first free flight with test pilot Ewald Rohlfs in control. By 1937, the aircraft had set an altitude record of 1200 feet, and at that point, Rohlfs cut the throttle, disengaged the clutch, and made the first autorotational descent to landing. Later the FW-61 was flown to 8000 feet, setting another record, and the same day an endurance record of 1 hour and 21 minutes and
a speed record of 76 mph were set.
Later in 1937, famed German woman pilot Hanna Reitsch began flying the aircraft, setting distance records before her startling demonstration flights inside the Deutschlandhalle area in Berlin, where she displayed the helicopter in free flight indoors in an arena area of 100 by 250 feet in front of thousands of people. Films of these flights were shown in the
United States, stimulating the development process in this country that led to the Sikorsky helicopters several years later.
A second prototype, E-EKRA, was completed in 1938, and this aircraft set several records, including a 143 mile straight line distance flight and an altitude record of 11,243 feet on January 29, 1939.
Due to questions of political unreliability and distrust by the Nazi Party , Focke left the Focke Wulf firm, but after the Luftwaffe realized the significance of his work, he was eventually allowed to form another firm, Focke-Achgelis, which developed the twin rotored Fa 223 transport helicopter, that was produced in small numbers during World War II.
The origin of this project began when, many years ago, I obtained a Pegasus 1/72 scale Focke Wulf FW-44 Stieglitz training biplane. It was a little crude, even by the standards of the day, so I held on to the kit, hoping that something better would come along. When Huma released their FW-44 kit a few years ago, my problem was what to do with the old Pegasus
kit. It did have some good points, but it really was fairly crude by modern standards, although the fuselage offered some promise. Then I got the idea of converting it to the FW-61 helicopter prototype, since the FW-61 was, in essence, a modified FW-44. The basic problem was research, since there was little information available on the FW-61.
Fortunately, the internet came through, and I was able to find a pretty good selection of photos, data, and even a small three view of the helicopter described as being a “factory drawing”. It wasn’t all that helpful, as it seems that the FW-61 went through several configurations, with the rotor assembly remaining constant while the braces and strut assemblies changed from time to time. The only solution was to pick a photo of the aircraft taken at a particular time and use that as a guide.
Two good sources for information, besides the photos I turned up on the internet, were Heinz Nowarra’s GERMAN HELICOPTERS, 1928-1945, a paperback published by Shiffer Military History, West Chester, PA, (ISBN 0-88740-289-5) published in 1990, and an article in WINGS (date unknown) by Mal Holcombe entitled “Vertical Lift: A Little Known Look
At German Helicopter Development Through the End of World War II, Which Preceded Our Own By Nearly Two Decades”. I suspect that the issue was published before 1990, but the copy I have has no documentation. Both sources have a lot of information, and the Nowarra book has a number of three views, including that of one configuration of the FW-61, purporting to be of “:factory” origin.
The Pegasus is not really that good a kit, but it is more
for this conversion. The fuselage needs some cleaning up, especially on the inside, as the modifications include revising the cockpit since
FW-61 was single seat. Once the interior is smoothed out, the interior
can be constructed. I simulated the steel tube structure with rod plastic,
adding details such as throttle and other controls.
The major problem was getting the right lengths of the various struts, and this was done mainly by trial and error. I scaled up the three view drawing to 1/72 scale, and went from there. The engine from the kit was useless, so I found another one from the spares box, although I’m not sure which kit it was from. It looks good, though, and that’s what counts. One thing I did forget to do was to weight down the nose, as the aircraft sits tail heavy, although the existence of a tailwheel shows that the aircraft sometimes could sit in that position, even though I couldn’t find a photo that shows it that way.
The rudder is straight from the kit, but the “T”: tail is scratch built. It was completely movable, and was not hinged as most elevator-horizontal stabilizer arrangements. Actually, it functioned more as a trim tab than as an elevator. The struts were all from plastic rod of varying thicknesses, but the main rotors were the biggest problem. After examining photos, I found that a pair of props I have in my spares box worked perfectly. They were from an old kit I built years ago of the Tupelov TU-2, the props of which were so bad that I replaced them.
Going on the theory of never throwing anything away, I now found that the hubs worked perfectly for the rotors on the FW-61. I trimmed off the prop blades and replaced them with card plastic with suitable airfoil shapes. These were strengthened by short lengths of piano wire and super glue. I gave them a slight “down” angle, as that is what shows in the photos. The propeller in front, actually a cooling fan, was cut down from a two bladed unit from the spares box. It is painted a wood color.
PAINT & DECALS
Finishing was relatively simple. The airframe was basically silver with schwarzgrau 66 top decking. The fin and rudder carried the typical red banner with the white disk and black swastika common on all German civilian aircraft of the period. Markings are typical Micro-Scale German code letters. Paints were Testors’ Model Master colors covered with glosscote lacquer.
I haven’t entered this model in any contests, but I was entirely satisfied with the result. It is a model of a historically significant helicopter, one that I would not otherwise have in my display cases. It does attract attention mainly because of its unusual appearance. And I am even happier to know that I salvaged a kit that I probably would not have built otherwise. Now the only question is, what can I do with the wings?
Brian R Baker
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