What kind of wind turbine is this?

  hi folks,

 for anyone interested in wind turbines or those folks just interested in interesting things i would recommend having a look at this new wind machine.

 bruce, i looked at the video shot a few more times trying to get my head around the center of rotation.

"The center of inertia of the entire system is located at a still point at the geometric dead center of the universal joint in the hub.  Thus there is no wobble or vibration at any speed or any rotor tilt angle."

  it looks like your universal joint/hub design takes all the side to side loads as well as the thrusting loads into the hub assembly and only lets through the rotational torque to the alternator/generator. nice...that also means it's reasonably easy to swap out different spec generators based on wind resources and power needs?

 i looked up that four digit airfoil. was that 12% by design
or trial and error.

 i hope you can tell us more about your choice for the powerplant as well as the gyroscopic precession correction methods you teased us about.

 all the best.

Gyroscopic precession seems pretty complex and mysterious at first, but in fact it is simply due to the fact that mass cannot change direction instantly - there is always a delay between the application of force and the movement of the mass.  In the case of a gyroscope, the response to a force is seen 90 degrees after the application of the force.

In other words if you press down at the 12 o'clock position, the clockwise-spinning gyroscope will dip at the 3 o'clock position.  This is simply because the mass passing the 12 o'clock position BEGINS to respond to the force, but it does not reach its full excursion until it reaches the 3 o'clock position.  No mass can respond instantaneously.

In helicopter rotor heads, the desired change to the pitch of the rotating blades must be applied exactly 90 degrees prior to the position that it will take effect.

In the VAWT/AR Tilt Rotor, gyroscopic precession must be compensated for, or the system will not run at its full potential TSR (Tip Speed Ratio - but for a VAWT, rotor speed relative to wind speed).  Here's why:

Let's say there's no wind and the AR is still, with its rotor level.  The wind begins to blow, and the rotor tilts into the wind, causing the airfoils to pitch correctly to produce rotational lift, and the rotor begins to turn.

Now the rotor starts to spin up, faster and faster, and as it does the effects of gyroscopic precession begin to take effect, causing the low tilt point of the rotor, which is supposed to be directly into the wind, to start to drift over to a point 90 degrees to the side. 

If the rotor were allowed to tilt 90 degrees off the windward mark, it would stop running very quickly, because the airfoils would not be positioned correctly to produce lift.  In fact, the airfoil that is swinging directly upwind - that should be perfectly faired into the wind - would start acting like a giant speed brake!

Early prototypes showed that without some means of correcting for gyroscopic precession, the turbines would settle into a tilt angle about 45 degrees between the optimal position and the show-stopper position.  The TSR would then be limited to around 1.5, whereas I've measured a TSR of 3 when correcting for gyroscopic precession.

How the VAWT/AR corrects for this is quite simple.  As I said before, as the rotor tilt angle starts to move away from the optimal windward position, the airfoil swinging in the upwind position begins to present drag because it is not perfectly faired into the wind.  However, due to the fixed cant angle of the airfoil relative to the rotor arm, any non-zero pitch in this airfoil is translated into a lifting force on the rotor arm, thus raising it back into its proper position. 

Remember, though, that gyroscopic precession is acting on this force as well!  But in this case it turns out to work in our favor, the final result of which is to nudge the rotor back into its proper windward tilt position.

So the airfoils are performing triple duty: 1) rotational force (produce rotor torque), 2) tilting force (orient the rotor to produce proper instantaneous airfoil AOA), and 3) correct for gyroscopic precession.  Once again, complex physics, simple design.

Cheers,
Bruce