Micro helicopter
As micro helicopters are helicopters designated suitable to transport only one person without any additional expense. In the literature, miniature autogyros are usually included in this category.
definition
A distinction is made between backpack helicopters and one- man helicopters , whereby the transition is fluid. A “real” backpack helicopter in which the pilot wears both the drive unit and the flight control on his body is not known to this day. One-man helicopters, on the other hand, have a load-bearing structure, usually in the form of a light frame construction, which carries the weight of the drive, the controls and the pilot and also absorbs the aerodynamic forces in flight. To compensate for the torque that is transmitted to the structure of the engine mount, a coaxial design is preferably used for the rotor. Alternatively, the torque transmission can be structurally excluded by attaching the drive to the rotor blade. This can be done by single-blade rotors with small piston motors arranged at one end or on the blade, or by a blade tip drive .
In recent times, the new class of microlight helicopters, such as. B. the Coax 2d from EDM-Aerotec and the Guimbal Cabri referred to as small helicopters. There is therefore no generally applicable definition and / or classification of miniature helicopters. Even modern gyroscopes are incorrectly referred to as miniature helicopters, especially in press reports.
history
Beginnings during the Second World War
The requirements of the military both in World War II and later during the Cold War can be seen as the trigger for the development of miniature helicopters, which began around 1940. The first known patent application was made by Adolf Weissenburger in February 1938 and is entitled: "Helicopter attached to the human body". The intended uses of the mini helicopters were: dropping of troops, personnel rescue system for fighter aircraft crews, combat field deployment. Occasionally a civil use was also propagated.
The small company Nagler-Rolz-Flugzeugbau developed some miniature helicopters and a backpack helicopter from the mid-1930s. Their first result was the NR 55 in 1940 with a 40 HP Argus engine that served as a counterweight for a single-blade rotor. The motor drove two propellers rotating in opposite directions over a long shaft, which were attached 2.27 m from the rotor axis. With a payload of 110 kg, the maximum take-off weight was 300 kg. Free flight attempts are said to have been successful in a hall.
The subsequently built NR 54, originally planned as a backpack helicopter, was a smaller, collapsible version of the NR 55. With an empty weight of 80 kg, the first version of the NR 54, equipped with a 24 HP engine, could not be used as a backpack helicopter . Only the second version, which differed from the first variant in that it used two 8 HP motors and a two-blade rotor, weighed 36.5 kg and was light enough to be used as a backpack helicopter. The NR 54 was probably the first foldable and portable micro-helicopter. It is doubtful whether this construction can actually be addressed as a backpack helicopter, since the pilot sat in a three-legged frame, on which all drive elements were attached to a central tube. Only four of the NR 54 were built and tested.
In 1941, Peter Baumgartl built the Heliofly I, the first "backpack version " of a gyroplane that weighed only 17.5 kg and that could be attached to the body with straps. After "starting" the rotor, it should be possible to slide the sports equipment from a mountain into the valley. The military Heliofly III / 57 derived from it had a drive in the form of two Argus motors, each with eight HP, which drove two counter-rotating single-blade coaxial rotors and each formed the counterweight at the end of the blade. The device, weighing 20 kg, was foldable and portable. The development was abandoned because the drive was too weak and more powerful engines were not available. With the Heliofly III / 59, Baumgartl also built a 16 hp one-man helicopter, which also only performed a few hover flights.
The Focke-Achgelis Fa 330 represented a one-man gyroplane from the time of the Second World War, which was built in large numbers.
post war period
One of the first post-war developments was the Pentecost HX-1 Hoppi-Copter , which was planned as a backpack helicopter, but could not be flown in this form. From 1951 at Kellett Aircraft Corp. developed KH-15 one- man helicopter had a blade tip drive with rocket engines. The empty weight was 110 kg. In the USA, two further military one-man helicopters were built in the mid-1950s, the Gyrodyne RON and the Hiller ROE , of which only 10 and 12 were built.
In Brazil in 1957 Baumgartl developed the PB 64, a one-man helicopter similar to the KH-15, but which used pulse tubes for the blade tip drive. From 1960 onwards, Dornier produced the foldable Do 32 E, which also had a reaction drive. Here, compressed air, which was supplied by a gas turbine, emerged at the blade tips. The VFW H-2 , with a curb weight of 152 kg, also had its maiden flight in the mid-1960s and used a reaction drive with compressed air, provided by a two-stroke engine.
At the end of the 1960s, the number of newly developed micro-helicopters fell sharply and are rarely found today. The Gen H-4 , a coaxial one-man helicopter, is an exception .
Developments with a similar objective
- Support platforms from the 1950s: De Lackner HZ-1 , Hiller VZ-1 Pawnee
- Rocket backpack
- Kite design: Ryan Flex Wing
- Inflatable wings: Goodyear Inflatoplane , ML Aviation Utility
Individual evidence
- ↑ Approval of ultralight helicopters in Germany from December 2016
- ^ Patent application Adolf Weissenburger
- ↑ von Gersdorff, Knobling, 1982, pp. 70 f.
- ↑ Photo of the NR 55
- ↑ Photo of the NR 54
- ↑ Pentecost HX-1 (Model 100) Hoppi-Copter . Retrieved November 22, 2017.
- ↑ Video of a flight demonstration of the Gen H-4 (accessed December 22, 2017)
