CoolIP index           


 Multi Autogyro Rotors On One Line

Ganged turbine rotors along a common axis is an old idea. Doug Selsam  has kept the scheme active on the AWE forum with his SuperTurbineŽ, based on torsional power transmission. SkyMill's concept begins as a single autogyro rotor modulating tug on one line, but there is no critical barrier to putting may such rotors on one line, boosting power.

The simplest method is to give each rotor its own section of leader line and connect rotors much as an ordinary kite train is built. A bit more complex would be rotors that can thread onto a continuous line and climb or descend as an independent carriage (kite messenger).

The topmost element could be an electric helicopter to initiate early launch to altitude and decelerate landing. This may well be a general AWECS launch solution.

The Multi Autogyro method offers high operational flexibility. It greatly multiplies the potential power of autogyro-based AWE, while avoiding difficulties of torsional power transmission.

CoolIP                       ~Dave Santos           Aug. 14, 2011            M3946

Comment and development of this topic will be occurring here.       
All, send notes, drawings, and photographs!

Terms and aspects:   

  • Early air and water patents for multiple rotating elements on one tether:          

Related links:


Commentary is welcome:

  • Interesting way. But on SkyMill the tether is several km,and the direction of winds differs according their height. The management of different directions of wind could be difficult, except (?) in the case where only rotors in the same wind direction are working.   ~ PierreB
    • Pierre,     Experience with kite trains shows they gracefully conform to varied wind by altitude. The commonest such condition is the Ekman spiral due to Coriolis effect, but all kinds of windshear would be passively "processed" by the collective array into a coherent output.

      Its also possible for each autogyro rotor to have considerable freedom of AoA by riding on a partial ball-joint, as a further optimization,              ~DaveS
      See Fig.4.   ~PierreB


  • At first consideration, such a scheme presents very attractive power-harvesting attributes. That said, my guess is, as far as our SkyMill type application goes, the "devil's in the details" for such a scheme, i.e., the orchestration of passing high tensions along such a chain of tethers will be (if lacking some highly inventive scheme that would allow this occur in a simple reliable operational fashion) fraught with many detail design/operational obstacles.  ~DaveL
  • DaveL,        Every scheme that has multiple flight "agents" working in a coordinated fashion has added control complexity. SkyWindPower describes a flock of close-flying units, presumably to avoid surface sprawl of widely spaced units. KiteGen also depicts coordinated flight in its stem farm and carousel animations..

    Fortunately, ganging units along a common line is a less complex way to aggregate power. A misbehaving unit is constrained by all the others, carried along rather than causing mayhem. The model of a tug-o'-war suggests reasonably tame collective dynamics, although one can envision fancier harmonics, like multiple traveling waves pumping the surface work-cell.

    A basic "long-line" AWE principle seems to be emerging; that lift might as well be harvested all along a kiteline, rather than bypassing a bunch of lift to only get it at some higher altitude.

    I also see "SkyMill Trains" as a competitive harvesting units under a potentially far larger cross-linked lifter array, for gigawatt-scale energy production,    ~DaveS
  • DaveS,  I am not as concerned about "group stability" (since active control for each rotor is at our disposal) as I am about other "devils in the details". For instance, I am referring to things like the "Ball-swivel" you refer to, or the launching and retrieval of such a chain of rotors.           ~DaveL
    • DaveL,       Lets forget the ball-swivel then, it adds little value.

      The more fundamental open question is whether it is easier (or cheaper, safer, etc.) to launch multiple standalone autogyro units versus launching multiple units along a "pilot-line" for equivalent power. 
  • Dave, are there some links to see these contraptions in action?    ~Darin Selby            Aug. 15, 2011
    • Darin,    This is not a "contraption" in the Rube Goldberg sense of messy complexity, but a reasonably "clean" modular design.

      This scheme looks just like Doug's demos of many rotors on a kitestring. The slight visual difference is the line is tugged, not torque,         ~ DaveS
  • Wouldn't a contra-rotating blade arrangement stabilize your airborne generator from precession forces?  ~DarinS

  • click through image for full patent.

  • Click image above for full patent.

  • Enjoy a Dave Santos drawing here

  • And shown is a Selsam hand-held electricity-generating torque-tether multiple rotors on single line with lifter pilot kite. He is holding the generator.
  • Follow a related discussion in forum:  AirborneWindEnergy/topics/3946 and following.