The MK IV "high tech" Yaw String - is the only Yaw String with a
clear turbulator base. Do not be fooled by imitations. This is
not your ordinary yaw string. The clear base raises the synthetic
yarn 0.038? above the canopy eliminating scratches and reducing
static charge. We use premium synthetic yarn and if the Yaw
String needs to be removed, it leaves behind no adhesive residue.
Each yaw string is meticulously handcrafted through a 28-step
proprietary process done under a magnifying glass which produces
the best quality and clarity. After production, each Yaw String
is inspected under a magnifying glass again by quality control.

W&W typically stocks Yaw Strings.

International Customers - Please note. If you have other non-free
shipping items in your shopping cart please select "FREE Domestic
US First Class Mail".

About the Yaw String

The yaw string is the most effective, yet least expensive,
slip/skid indicator. It is made from a piece of yarn mounted in
the free airstream in a place easily visible to the pilot. The
yaw string indicates whether the pilot is using the rudder and
aileron inputs together in a coordinated fashion. When the controls
are properly coordinated, the yarn points straight back, aligned
with the longitudinal axis of the glider. During a slipping turn,
the tail of the yaw string is offset toward the outside of the
turn. In flight, the rule to remember is simple: step on the head
of the yaw string. If the head of the yaw string is to the right
of the tail, then the pilot needs to apply the right pedal. If
the head of the yaw string is to the left of the tail, then the
pilot should apply the left pedal.

Installation instructions

Determine the ship's true centerline for mounting the MKIV base
and included an optional center index dot. A good method is to
stretch a string from nose to tail. Tie or tape one end of the
string to the glider nose and the other end to the top center of
the horizontal stab or vertical stab. Stand away from the front
of the glider and sight down the string to be sure it's straight
and on center all the way from nose to tail. You may need to lift
and move the string from one side or the other where it crests the
curve of the canopy. Place a piece of masking tape under the string
just forward of where you will install MKIV and mark the centerline
on tape with a pen. Move the string off to the side and clean the
area for MKIV with denatured or rubbing alcohol and a soft cloth
(I recommend microfiber). Move the string back to the center.

Make a paper template guide to ensure an easy and accurate
installation. Cut a strip of paper approx 2? (50mm) wide by
about 8? (200mm) long. Position the MKIV base at the center of
this strip so that only the curved portion at the back of the
base is off the paper (align the two corners of the rounded base
with the edge of the paper). Trace around the pointed front of
the MKIV base with a pencil (no ink) to form a "V". Cut out a
"V" with scissors and discard. Place template with "V" cutout
under string (apex of template "V" cutout facing forward - open
end facing aft). Sight down on the template strip to ensure it
is perpendicular to the string, tape ends in place.

Yarn is supplied long, cut length to suit, and tie a simple
overhand knot  1/4 ? (6mm) from the end to prevent fraying. If
using an optional center index dot (this is the reflective dot
located loose in the MKIV package) temporarily place the MKIV
base in template "V" and gently stretch the yarn aft. Mark the
desired dot location with tape on the outside of the canopy. Dot
will be installed on the INSIDE surface of the canopy.

With the "V" template and center mark in place, remove the
string. Clean the inside canopy surface where the index dot will
go with denatured or rubbing alcohol. Hold the index dot between
finders and bend one edge gently away from the reflective side
to loosen the dot from backing (do not crease). Use the tip of a
clean utility knife, or other small knife blade or sharp tweezers,
to lift the edge of the dot from the liner. Then using a knife
tip or tweezers, position the dot before smoothing it down with
your finger. Use caution to avoid scratching the canopy with a
knife blade. With the dot installed, close the canopy.

Hold the MKIV base only by edges or yarn and remove the red
adhesive liner by lifting a rear corner edge with a knife tip
so you can grasp the liner and peel it off with tweezers or
fingernails. Re-attach about  1/4 ? (6mm) of the pointed tip of
the removed liner to the back center of the base adhesive to
form a temporary "handle". CAUTION! do not touch the exposed
clear adhesive surface with anything but the removed liner or
allow yarn to contact it as this will impair the optical clarity
of the base. The adhesive is very tacky and once it touches the
canopy plastic you will be unable to reposition the base without
damaging the MKIV. Steady your hand against the canopy and hold the
base using the "liner handle" in position over the "V" template
cutout. Maintain a slight and even gap on both sides of the "V"
cutout and base. Do not butt the MKIV base tightly into the "V"
or the adhesive may overlap or touch the paper template.

Okay, the goal is to get it on straight and with no bubbles under
the adhesive, take it slow and this will be easy. Touch the pointed
end of the base to the canopy first while holding the back of
the base up a bit, away from the canopy using the "handle". Use
a smooth object (retracted pen tip etc.) to slowly work the base
down while watching the adhesive progressively make contact with
the canopy, this is easy to see and looks like water between two
sheets of glass. Before getting more than half the base attached,
and while bending up the back of the base to keep it off the
canopy, grasp the rear of the base by edge corners and gently
remove the red liner "handle" by peeling off ( twist "handle"
slightly and pull in line with canopy surface, not in line with
base surface - so as not to stretch adhesive). Work the remainder
of the base down. With a finger, firmly press the base down for
several seconds. You may fly immediately, but please don't wash or
disturb the MKIV base for 24 hours to allow full adhesive strength.

After several years of exposure, you may wish to replace the MKIV
as the yarn wears or fades. To remove the old base lift edge and
"roll off" with finger pressure. Or use a fingernail, knife blade,
or similar tool to lift an edge of the clear plastic top layer
using caution not to touch the canopy with any tool. Grasp the
edge of the base with fingers or needle nose pliers and slowly
peel off. Any remaining adhesive residue will cleanly roll off
with finger pressure.

Inclinometer

Another type of slip/skid indicator is the inclinometer. Like
the magnetic compass, this instrument requires no electrical
power or input from other aircraft systems. The inclinometer
is influenced by centrifugal force and gravity. Mounted in the
bottom of a turn-and-bank indicator or mounted separately in
the instrument panel, the inclinometer consists of a metal ball
in an oil-filled, curved glass tube. When the glider is flying
in coordinated fashion, the ball remains centered at the bottom
of the glass tube. The inclinometer differs from the yaw string
during uncoordinated flight. The ball moves to the inside of the
turn to indicate a slip and to the outside of the turn to indicate
a skid. Remember the phrase, "step on the ball" in reference
to the inclinometer; it helps coordinate the turn using rudder
inputs. The long glider wing tends to increase the adverse yaw
effects from the ailerons and requires more rudder control than
many aircraft. Source -Glider Flying Handbook.

Click link for Inclinometers.

  https://wingsandwheels.com/avionics-instruments/slip-skid-indicator.html