Re: How does adverse yaw work?

Dear friend,

   Sometimes I have the chance to pilot a glider that belongs to a 
group of enthusiasts for flight.
   Adverse yaw really IS a nasty thing, and it make every "rookie"
freeze as we try (I consider myself one, even after 20 flights...)
to avoid it using pedals, applying more rudder...
   Just try to imagine a leveled flight.  That's all ok, the flow pattern 
around the left and right wings is identical.  Now imagine that a little 
pesky flying goblin decides to "take a ride" on your plane, more exactly 
over your left wingtip (somewhere near the position where ailerons use to 
be placed).  Needless to say, your "leveled" flight just says "bye, bye"...
   What happened?
   Easy!  The drag over you left wing raised (due the "goblin" presence) 
and it forced you to apply right rudder(opposite direction) in order to 
maintain straight flight.
   Now, you guess!  That left "goblin" has the same basic "property" as 
your left aileron when you turn it down.  It raises drag on left wing.  But 
"wait", you might say, "when left aileron goes down, right aileron goes 
up!".  Yeah, but wing pressure pattern over is different that from under.  
Usually under the wing there is more pressure than over (that's why 
airplanes fly, after all...).  More pressure at the aileron, more drag it 
produces, so instead of nullifiying themselves, a little, but VERY 
noticeable force results, dragging your downed aileron back.
   Now that's just a matter of putting pieces together.
   When you fly and want to turn right, first apply your control stick 
right and some seconds after apply right rudder, pulling up a little 
control stick to avoid loss of altitude.  Correct coordination of movements 
between these two controls results in a perfect maneuver.  However, things 
aren't so easy...
   Control stick right results in left aileron down (and right up), so we 
have a resultant left drag.  So it's bizarre, but when the airplane just 
happens to roll right, its nose begin to move left in the opposite, or 
adverse, direction.  Tricky, but just apply a little more rudder than 
necessary at the begining and after rolling you can apply less force to the 
rudder, just the necessary amount to maintain a coordinated turn.
   Hope you have understood, after all those "rights" and "lefts"!