The definition of `rotor' kite is in itself controversial. It has come to mean any kite which uses or depends on rotation in some manner to fly. The kites are sub-classed into some general categories, basically determined by the direction the axis of rotation is relative to the wind and ground...
Because of the unusal nature of this kite, a huge number of patents have been taken out on this kite. These patents use to be freely available on the net, but now the main web site is more restricted making it harder for people to just take a quick look. I will point to them in any case
Rotor Kites which spin around a horizontal axis, parallel to the
ground and perpendicular to the wind. The top side of the kite moves with
the wind and bottom rotates into the wind.
The traditional version of this kite uses two concave surfaces with
vertical disks either at both ends, or occasionally in the middle. The
concave surfaces ensures that the rotor spins in one direction only. They
also make this style of rotor spin very smoothly. The photo left is a
traditional rotor taken at the Dieppe 2000 Kite Fest
(France).
The modern version of this kite known as a ''UFO Sam'' was first published by Kenneth Sams in a children's book called ''Flying Toys'' (See Modern UFO).
The big difference between this style and the traditional rotor is that it uses completely flat surfaces! This however means that the kite alternativally catches and releases the wind as it rotates, producing a strange vibration on the kite line (which must be a streachy line to allow this or the kite will not spin correctly). The flat surfaces on the other hand means the kite is much easier to build as you do not need to shape the concave surfaces of the traditional rotor.
Another rotor kite which appeared in the 1970's was the rotor airplane, with a long body, and rotating wings. The body
increased the stability of the kite, allowing the rotating wings to become
longer and more tappered, increasing the efficiency of the rotor lift
effect. I had one of these as a kid.
Autogyro, or gyro glider, which have horizontally rotating blades,
the axil being close to the vertical. These include the Gyro Kite which
is commercially sold and Patented. Note
that while these kites are helicopter like, there is no motor, just the
action of the wind to spin a thin blade into one large spinning wing. I have been in email contact with the original patent holder, Alex Kattas, who has been facing legel problems with the manfacturer and distributor for this kite. As such the kite should not be commercially for sale at this time.
Basically to get them to work you have to get the rotor up to high speed before the kite will takeoff and remain stable. Also due to the high speed of the rotor, (100 Km/hr is not unheard of) the large heavier models (usally made of wood) can be very dangerious. Extreme caution and patience is advised.
If you are interested in Auto-Gyro Kites, I suggest you wander over to the
Rotorcraft Kite
Project, for more information and photos about this kite. You can
also send an email request for a copy of a plan, for a mini-rotor to play
around with. Warning some metal working is required, do it isn't for a
casual builder.
Alturnativally look at the Chupp Rotor (Type-H) Autogyro Kite Plan (see photo right). This plan is simpler and looks to be safer and more stable, due to the extra fins and wings. Again some advanced precision construction is needed.
A simular kite is Don
Mathews famous ''Windmill Kite'' (see photo right) which uses four
rotating turbines to act as the kites sails. This is not exactly the same
principle as an autogyro, but in is in the same class of vertical axil
rotor kites.
One minor point about these kites is that due to the rotation the kite
tends to fly off to one side. As such you could fly two of them rotating
in different directions, side by side on a forked kite line. When flying
properly they will not interfere with each other. Pictured right is my own
set, which my nephew calls 'jet engines', due to the look of them spinning
together in the sky.
WARNING: As the axis of rotation is with the wind, the kite lines twist up something increadible. A good set of swivals and other devices attached to the kite line is required to prevent the whole flying line twisting up.
A typical example of a rotating box is a ''Spinning Jenny'', and as with most rotors has lots of different patents. The latest known patent is US 5833174, which will reference all other simular patents. However better detail is given on the Spinning Jenny web page. The kite is simular to but definatally NOT the same, as a circoflex kite (which is a thin ring instead of a long tube, and does not rotate at all) or a spinning turbo tail, spin sock, or ''turbine'' (which produces drag but no lift). It is really just a box kite which spins.
Some plans (in Italian) is available for a rotating 2 cell box kite called a Revolver and for a rotating snowflake box kite called a Girasole.