Hafner Rotachute
| Hafner Rotachute | |
|---|---|
|
|
| Type: | Experimental aircraft , gyroplane |
| Design country: | |
| Manufacturer: |
F. Hills & Son |
| First flight: |
February 11, 1942 (in vehicle tow) |
| Number of pieces: |
about 8 |
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The Hafner Rotachute is an experimental aircraft designed as a gyroplane, designed by Raoul Hafner and built by Hills & Son in Manchester.
history
Against the background of the experience with the defeat of France and the evacuation of the British expeditionary force in Dunkirk in 1940, the British War Cabinet decided to set up an airborne task force. This should include 5000 men and consist only of volunteers.
development
In developing the equipment for the force, unconventional approaches were also considered and tested. In November 1940, the Austrian Raoul Hafner, who was released from his internment for this, designed a non-powered gyroplane in collaboration with aerodynamicist JA Bennett, which was supposed to transport one soldier at a time. Hafner was convinced that with the support of a rotor much more precise landings of paratroopers would be possible. It should also make it easier to set down agents during secret operations, medical aids and doctors or even fire extinguishers in inaccessible areas.
Initially, it was planned to be a simple backpack device. Hafner changed the design after a short time and designed a light tubular steel construction with a rotor arranged above it. The version accepted by the Royal Air Force complied with tender requirements 11/42 . The rotor blade structure was manufactured by F. Hills & Son in Manchester, while the rotor blades were manufactured by H. Morris & Co. in Glasgow.
testing
In the first phase of execution of the program, a dummy called H. 8 was built. After initial attempts at a simulator in the form of a Rotachute replica, which was hung in a frame behind a stationary Whitley bomber, were not practical because of the strong turbulence, further training was carried out with a Cierva C.30 A gyroplane. For this purpose, the control system of the Rotachute was installed in the front cockpit of the C.30. The well-known glider pilot Robert Kronfeld was among the three test pilots who carried out the tests as volunteers . First the device was attached to a truck, later it was fitted with wheels and pulled on a 40 m long rope behind a Humber car. The first towed flight took place on February 11, 1942. In the twenty second flight, a height of two meters was reached. After releasing the rope, the flight ended with the device rolling over. The second flight on February 16 also ended in the same way, after which further testing was relocated to Snaith, which had a longer runway of two kilometers. Due to the longer towing time that this made possible, climbing and sinking could also be tested. The rear part of the device has also been modified by lengthening and increasing the rigidity of the “bag”. The name was now Rotachute Mk. II. The first flight of this variant was on May 29, 1942 behind a Willys Jeep . With further flights a flight time of up to three minutes was achieved.
On the Mk. III, the rear part of the unit was no longer clad in fabric, but had plywood planking and a real wooden tailplane. Heights of up to 30 m can be reached on a 92 m long rope. The first free flight on June 9th, during which a forward speed of 50 km / h was reached, was successful. When towed by a Tiger Moth , the flight and release height of the Mk. III with the registration number P-1 could be increased to 1000 m and the flight time increased to forty minutes, whereby a very good, gyroplane-like flight behavior was noted. The flight tests of the Mk. III could be continued until October 18, 1943, when, after a flight with Kronfeld at the controls, the machine was severely damaged in a hard landing.
The next version was the Rotachute Mk. IV with an improved tail unit, which was tested from April 29 to May 20, 1943. After that, the RAF made the decision not to equip the airborne landing forces with the Rotachute. The last flight of a Rotachute took place on October 18, 1943.
Further use
A copy was delivered to the USA and tested there in flight from December 1945 to January 1946 by the General Engineering and Consulting Laboratory of the General Electric Company (GE) and the Air Materiel Command of the USAAF . In 1947 Igor Bensen , then an engineer at GE, developed the Gyroglider, an aircraft that was very similar to the Rotachute and was the starting point for a whole family of other such designs.
construction
The "fuselage" of the device was open at the front and in the first two versions had a sack-like fabric cladding of the framework, which inflated in the draft. The stabilization surfaces at the rear were also integrated into the fabric bag. A wooden muffled runner was used for landing. The rotor blades, which allowed 375 revolutions per minute, were also made of wood. The control took place via a hanging control stick attached directly to the rotor head. Due to the overhead arrangement, the usual reactions to control commands compared to the conventional control were exactly the opposite. So z. B. be pushed forward to rise the joystick. There were no rudders, the rotor was tilted to turn. Besides the soldier himself, a Bren machine gun with 300 rounds should be able to be transported. With a curb weight of just 35 kg and a total weight of 134 kg, the Rotachute was the lightest manned aircraft developed to date.
One of the main drawbacks of the device was the need to bring the rotor to a specific speed before use. During testing, this was done by an escort vehicle, as was to be done for a large number of devices under operational conditions, remained one of the unsolved questions. A mini gyroplane with a drive, called a Rotacub , was therefore proposed, but not pursued further.
Technical specifications
| Parameter | Data |
|---|---|
| crew | 1 |
| length | 3.0 m |
| height | 1.5 m |
| Rotor diameter | 4.6 m |
| Rotor area | 16.4 m² |
| Rotor speed | 375 min −1 |
| Slightest sinking | ? m / s at? km / h |
| payload | 99 kg |
| Structural mass | 34.5 kg |
| Max. Takeoff mass | 134 kg |
| Minimum speed | 34 km / h |
| Top speed | 173 km / h |
Whereabouts
The original Rotachute Mk. III P-5 is on display at the Museum of Army Flying in Middle Wallop .
See also
literature
- Ryszard Witkowski: Allied Rotorcraft of the WW2 Period , Stratus sc, 2010, ISBN 978-83-89450-97-5
- Philip Jarrett: Nothing Ventured ... - Part 17 . In: Airplane Monthly August 1991, pp. 470-476
Web links
Individual evidence
- ↑ List of Bensen constructions (accessed on September 3, 2015)
- ↑ Airplane Monthly August 1991, p. 476