Tom Knauff's newsletter
At 03:26 02 July 2008, Bill Daniels wrote:
Examples of the questions include:
snip
During a steep, continuous left hand turn, how are the controls held?
A. Left Aileron, right rudder, back stick
B. Left aileron, left rudder, back stick
C. Right aileron, right rudder, back stick
D. Right aileron, left rudder, back stick
Q#2: This one needs a some qualification since it depends on the glider.
Obviously, into-the-turn aileron (left in a left turn) would never be
used
in a continuous turn so the choice is between C and D.
I find many gliders, once stabilized in a turn, will track nicely with
the
string centered with my feet off the pedals indicating no rudder is
needed
at all. Only opposite aileron (right in this case) is used to hold off
the
overbanking tendency - this right aileron provides all the left yaw
(adverse
yaw) needed to center the string. Gliders with less adverse yaw will
need
some into-the-turn rudder (Answer: D). Gliders with a lot of adverse
yaw
may need a little out-of-the-turn rudder (right) (Answer: C).
One must add that the Dick Johnson technique of using a slight slip also
works nicely and adds a little to the performance. Dick holds
out-of-the-turn rudder to oppose overbanking and keeps the stick
centered.
In my experience, this works best on gliders with generous dihedral and
without winglets or polyhedral.
snip
Bill Daniels
I notice from the back seat in a left turn that the yaw string for the
front cockpit is slightly more to the right than the one in the back; I
believe this to be because the front one is farther from the center of
lift -- or the tangent of the turning radius.
This leads me to believe that the rudder, also displaced from the center
of lift would likely align itself with its own relative wind and would
thus be slightly to the left if unattended.
I do not think of this as holding bottom rudder. I was taught to hold a
little top rudder and it might just be that a bit of pressure on the top
rudder would place it somewhere between the place it would naturally seek
and perfect alignment with the fuselage if not actually to the outside.
I do note that if the nose drifts too low in a turn it is much easier to
move it back to the proper position by applying top rudder than it is to
add more back pressure on the stick. I believe this is also much safer --
a little bit of slip instead of lowering the airspeed with the stick while
holding top aileron and bottom rudder, the classic setup for spin entry.
React, Bill?
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