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Description of the very small and light Proxflyer Micron / Microflyer

The original Proxflyer Micron was in 2003 the smallest and lightest electric powered
contra-rotating coaxial-rotor "helicopter" ever built. It is battery powered and it uses
the Proxflyer concept to give it inherent stability. It is built both to prove that the new
Proxflyer concept works for really small helicopters and also as an answer to a challenge.

The total weight of the Micron, 6.9 grams is not in any way the limit for what's possible, it is
the result of a rare encounter between to very passionate model builders. The autumn of 2003
Alexander Van de Rostyne and Petter Muren met in Brussels and took up the challenge to
build the smallest and lightest helicopters ever presented to the public - using two
very different concepets, the Rotorix concept and the Proxflyer concept.

The Microflyer is a upgraded version of the original Micron. With a new battery the
weight has increased to 7.8 grams, and the flight time is now over 10 minutes.

Key specifications, components and materials used in the Proxflyer Micron / Microflyer:



Motors (x2):



Flight time:

    128 mm (2 contra rotating 4-bladed rotors)
    Carbon rod 0.5mm and 0.7 mm from WES-Technik
    Aramid 30 g/m2 fabric from CST
    124 mm long, balsa and 0.1 mm carbon plate, 0.5 rod
    Ball bearings (5) 1 mm from WES-Technik
    6 mm, 6 ohm and 4 mm, 30 ohm from Didel
    1 x 3.7 V, 45 mAh Kokam cell from WES-Technik
    90 mAh E-tec cell for the Microflyer
    3 (uses 2) channels FM Radio with ESC from MPS
    One motor drives both rotors with one rubber band
    twisted. Vertical tail rotor for yaw control
    6.9 grams (ready to fly, incl. battery and radio)
    7.8 grams for the Microflyer
    2 minutes, (1 minute continues)
    10 minutes continuesly for the Microflyer

Because of the new Proxflyer concept, this helicopter is much simpler and has
much fewer parts than other model helicopters. The helicopter is passively stable
in hover and during forward flight and has no need for cyclic control. It is controlled
vertically and in yaw (rotation), and it can be operated with a standard RC transmitter.

STABILITY: Most other "stable" model helicopters, including toy helicopters from
i.e. Asia, achieve some kind of stability by utilizing centrifugal forces and gyroscopic
effects to keep the rotor and helicopter horizontal at all times, thus preventing it from
entering into oscillations or becoming unstable. The Proxflyer, however, uses a different
approach (patent pending). In stead of trying to keep the rotors in a horizontal plane, they
are arranged in an innovative way so that they do the complete opposite. Triggered by the
smallest horizontal movement, the rotors tilt up, creating a horizontal force stopping the
motion almost before it starts. The helicopter is kept at the exact same position relative
to the surrounding air. The Proxflyer concept gives the helicopter incredible stability,
but limits the maximum horizontal speed. The concept, without relying on centrifugal
forces alone, give the rotors good and quick stability with respect to the rotor shaft as
well, and it will therefore promptly and smoothly let the helicopter move in the
same direction as it is tilted by i.e. manually shifting the CG forward. As can
be seen in the video clips, it may be controlled very precisely.

Key benefits of the helicopter:

  • Absolutely stable without the use of any gyros or autopilots

  • There are no servos, actuators, rods, links, gears or other moving part

  • The whole helicopter is operated and controlled by 2 electric motors
    (1 motor for the main rotors and one extra motor for control)

  • Forward movement is achieved by manually shifting the CG forward

  • The rotor blades are encircled by a ring that supports and protects them

  • It is very efficient, all the power is used to generate lift

  • It is silent, the mechanical drives and the rotors generate no noise

  • There are no vibrations

  • It is safe

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