Wills Wing Sport 2 155 Owner'S Service Manual Download

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Trimming Your Glider in Pitch

You will find that the on the Sport 2 the basetube position at trim changes with VG setting. At VG
loose the glider will trim with the bar farther out, and as VG is pulled on, the basetube trim position will
move back. The trim speed will normally not change by more than one or two mph at different VG
settings. The Sport 2 will normally be trimmed at near minimum sink speed or slightly above.

At tighter VG settings, the amount of pitch pressure felt as you move away from trim also decreases.
At VG loose, the pitch "well" is very defined; the pitch force increases quickly as you pull in from trim
speed. At tighter VG settings, the pitch well becomes more shallow, and the pitch force increases
much less as you pull in from trim speed. At VG full tight, the pitch pressures when pulled all the way
forward may be as light as 8 to 12 lbs per hand.

Overall pitch trim is affected by several factors. Among the most significant is the location along the keel
of your hang point (commonly, if mistakenly, referred to as your “CG location"). The farther forward your
hang point is, the faster the glider will trim, the less effort will be required to fly fast, and the more effort
will be required to fly slow. If the glider's trim is too slow, it will make the glider more difficult to control
in roll, especially in turbulent air and when the nose pitches up on entering a strong thermal.

On the Sport 2, hang loop fore and aft position is adjusted by repositioning the kingpost base bracket
attachment to the keel. The bracket is secured by a bolt through the keel. There are three holes in the
keel to allow three positions in increments of 5/8" over a range of 1.25" of adjustment.

We recommend that you not stow your glider bag, or any other cargo on the glider.
The practice of putting your glider bag inside the sail, for example, can drastically
alter the pitch trim and static balance of your glider, and adversely affect its flying
and landing characteristics. The best place to carry your glider bag or other cargo
is in your harness.

Another factor that can affect pitch trim is the adjustment of the keel pocket rear support strap. If this
strap is too tight, it can slow the trim speed. With the glider fully set up on the ground, and the VG set
full loose, there should be 0.5" of slack in this strap.

Finally, the adjustment of the sprogs will affect pitch trim at tighter VG settings, although not at VG
settings looser than about 2/3. If there is excessive "transient trim" (increase in trim speed at tighter
VG settings), it is an indication that the sprogs are set too low. If there is a marked reduction in trim
speed between VG 2/3 and VG tight, it indicates that the sprogs may be set too high. When the sprogs
are set properly, the trim speed will normally remain the same, or increase slightly up to VG 3/4, and
will not be significantly higher or lower at VGT than at VG 3/4.

In the absence of the use of tufts, it has become common for pilots to talk about bar position, or about
indicated airspeed, when trying to communicate how to trim a glider properly or how to fly a glider at
the proper speed for a given situation. The problem is that these methods are unreliable and inconsis-
tent from one pilot to another even on the same glider. The angle at which your harness suspends your
body in your glider has a great deal to do with your perception of the bar “position” relative to your
body. Airspeed indicators vary in their indicated airspeed depending on the make of the instrument, its
calibration, any installation error, etc. The use of tufts gives you an absolute first hand indication of the
actual aerodynamic event associated with two critically important airspeeds on your glider. It is a
potentially useful tool that may improve your flying.