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gyro sailor

small catamaran with a autogyro-like sail/rotor
  [vote for,

This idea is based on some boat i saw on TV long time ago, and the bensen autogyro 'kites' or gliders of the '50-'70 of the last century. Basically it is a small but fast catamaran. On it is a spaceframe pyramid about 4 meters high made of aluminium tubing. The top of this pyramid has a rotor attached to it, about 6 meters in diameter. Turning this rotor partly into the wind will make it rotate and generate lift along the axis of the rotor. The same mechanism works in autogyro's or in helicopters when they lose power. The rotor acts just like a sail most of the time. It will be a bit less efficient because of the friction losses from the rotor etc, but will have some benefits that you can use the momentum of the rotor to move forwards when normal sails would stall or be forced to tack. The kicker is in the fact that the rotor can be tilted from vertical-starbord to horizontal to vertical-portside. When you set it horizontal, you could turn into the wind and: Fly Away! You wont be able to fly very far as you will be a not very efficient glider after takeoff. But with enough flywheel momentum in the rotor that you can convert into height, you will be able to make jumps of about 10-50 meters. Offcourse you need to reach the optimal rotorspeed first, probably by tacking downwind. Then you turn into the wind and with the help a a wavetop as ski-jump, you fly over the surf to the beach to make a gentle touchdown in front of your admirers :-o

Practical implementation: The rotorhead consists of a plate with a big ballbearing (from a car maybe?). The user can hook on more rotorblades depending on the wind conditions. (you need something to counteract imbalances, have not thought of something yet). beneath the rotorhead are two hinges: The first hinge is to set the angle of the rotor to the wind, and is moved by a small wing mounted on a boom pointing aft (& down to allow for flapping of the rotorblades). The angle of attack of this wing is set by the user via a bowden(clutch)-cable. This ensures a constant angle of attack in shifting winds. The second hinge (perpendicular to the first) is used to move the rotor from vertical to horizontal and is operated by the user. The hinge-rotorhead assembly is mounted on a mast that can rotate 360 degrees. The hinge and brake controls are mounted on the lower end of this mast. A breaking system allows the rotor to be stopped or slowed down. (this was the problem with the ancient design I saw on tv once)

So there you have it: a rotorboat with a gyrosail?

nietsch, Mar 21 2004

(?) Autogiro Boats http://www.users.gl...chts/auto/hist1.htm
Scroll down for Brab's 1933 autogiro Redwing. [phlogiston, Oct 04 2004]

(?) Autogiro sailboat pages http://uk.geocities...chts/auto/hist1.htm
I think is the same doc as the above link lost. [blimpyway, Jul 27 2006]


       Catamarans do not have any ballast weight apart from the crew. The weight of the rigging comes into play mostly when heeled over. With a cat you don't want to put it that far anyway, because the stability quicly decreases once you lift one hull out of the water. It is pretty straightforward to increase a cat's stability by increasing it's beam. A gyro driven cat falls out of every class regulation anyway, as these mostly restrict cat's beam.
nietsch, Mar 21 2004

       //and generate lift along the axis of the rotor//   

       How is this supposed to work? You expect to generate enough lift to propel the boat to windward? Not likely. When a helicopter loses power, it gets enough lift by auto-gyrating to slow it's fall, but not to enough to fly. I think you'll need some horizontal gravity to get this thing going.
oxen crossing, Mar 22 2004

       [oxen] The horizontal gravity is not needed. The thing that makes the rotor turn is air passing over the rotor. On a auto-gyro this is called airspeed, on a sailboat it is called wind. (after all it is not gravity rotating the rotor;) The rotor's axis is held at 80-85 degrees to the wind by a wind vane.   

       You can sail to windward (tacking) just like other sailboat. Just zig zag until you are there.
nietsch, Mar 22 2004

       [13lack]: sorry no picture (yet) what is it you can't see for yourself?
nietsch, Mar 22 2004

       This was actually nicely baked back in 1933 by the extraordinary Lord Brabazon of Tara (later Britain's Air Minister). He owned a Bembridge Redwing (Isle of Wight) and since one of the class rules stipulates a maximum sail area, but no limits on how the area is arranged, he constructed probably the first successful autogyro rig. See link. I think the AYRS guys are still exploring how this could be applied using modern materials and airfoil technologies.
phlogiston, Mar 22 2004

       Kevin Costner - Water World. A Darrius rotor, I believe.
Ling, Mar 22 2004

       Wow. Looks like it can work. Two questions remain. 1. Why the elaborate pyramid structure then? Seems like extra windage to slow you down. 2. How would this handle extra light air? I mean if you are becalmed, and then you get a light puff, if the rotors aren't turning, and the wind is too light to get them going, won't you end up going backward? If so, this is a huge drawback compared to regular rigs, which can easily take advantage of light puffs to get moving, if you know what you're doing.
oxen crossing, Mar 22 2004


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