Mirrored Yaw Bearing and rotor direction

[daleh007]

What would happen if you were to mirror the design of the yaw bearing? So, if instead of furling to the right as you face the rotors it rotates or furls to the left? I'm sure this makes no difference whatsoever except maybe, and this is really my question, what about the direction of the blade rotation? Would the blades/rotor then have to rotate CCW as opposed to the CW rotation of a right sided furling bearing?

Daleh

[Flux]

I doesn't really matter which way it furls or which way the blades rotate.

Flux

[Norm]

   Like Flux says it really doesn't make any

difference, but I believe just on the rotor

direction you get a different reaction depending

on if it is spinning cw or ccw and if you take

a bicycle wheel spin it cw then yaw it to the right

and observe what happens then yaw it to the

left and observe what happens...spin it ccw and

repeat the procedure...I think in one instance it

will deflect toward your knees and spinning in

opposite direction will deflect away from your

knees...so if that were your rotor and the blade

tips didn't have much clearance from the tower...

   I think one of the Dans commented on this

quite awhile back.

          Just what I remember and I may

    be all wrong...so it may or may not help.

hopefully it will.

                 ( :>) Norm.

[daleh007]

Interesting, what I was thinking about is the combination of the CW rotation and a left side furl as it relates to air movement across the slope or face of the rotor in the furlling action. Air is moving across the face of the rotor and would exit across the top of the rotor in a CCW rotation and across the bottom of the rotor in a CW spin assuming you are looking at the downwind blade. I suppose this is the part that either moves the blades up or down (to the knees) as you put it?

Daleh

[Flux]

No it's gyroscopic force that causes the movement. this force is only present during a yaw.  During a sudden gust it is more likely to yaw more rapidly as it furls than it is likely to from general turbulence. Also during a gust the bottom of the blades are blown back towards the tower so it would be safer to arrange things so that the gyroscopic force is tending to tip the blade bottom forward and the top back.

This is only a secondary issue and it is far better to have adequate clearance in the first place, but it is a nice refinement that costs nothing except the trouble of finding out which rotation you need.

I think for clockwise looking at the prop from up wind the offset needs to be to the left of the pivot but the mathematicians will correct me if I have got it wrong.

Flux

[Ungrounded Lightning Rod]

I think for clockwise looking at the prop from up wind the offset needs to be to the left of the pivot but the mathematicians will correct me if I have got it wrong.

I think you have it right.

The spinning wheel "drags the twist along with it" by a quarter turn.

With the offset to the left of the yaw bearing and clockwise rotation (both as viewed from the front), a sudden yaw from a gust will move the right side (3 oclock) toward you.  The right side is moving down, so it will carry the "move toward you" with the rotation by a quarter turn (to 6 oclock, where the blade passes the tower).  So the gyroscopic effect will try to push the blade away from the tower.  (Similarly it will try to move the blade toward the tower at 12 oclock, but there's no tower to hit up there.  B-) )

Yawing back into the wind after the gust is over does push the blade toward the tower.  But the yaw is slower (and the blade may be moving more slowly) so there's much less force to deflect the blade.