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irBorne WindSports
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Fun MANUAL
Issue Date: 1 October 2001 Page 14
Section 10 TUNING
Your Fun was test flown and delivered to you in good trim. If, however, any adjustments are made to your
glider, we recommend that they be recorded in your maintenance log at the rear of this manual.
If you feel that the glider requires adjustment to trim in the roll or pitch axis you should check that the problem
is not caused by something asymmetrical in the frame or battens. In order of priority, check the following:
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Ensure that the wires, including reflex bridles, are correctly routed;
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Check the battens against the profile;
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Check that the keel is straight;
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Check that the sail is correctly mounted on the leading edges.
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Check leading edges are straight and the rear leading edges are located correctly;
Pitch Trim
Standard position of the hang loop is outline in the compliance schedule at the rear of this manual.
To make the glider trim faster move the hang loop forward 10-15 mm. To make the glider trim slower move
the hang loop rearward 10-15 mm. The velcro tensioner should be firm to secure the loop.
A heavier pilot may make the glider trim slower than a lighter pilot. The heavier pilot causes an increase in
twist through extra leading edge flex. The hang loop should be moved forward if this is the case.
Pitch Stability System
Stability in the pitch axis is provided by reflex in the root section. Alterations to the lengths of rigging, airframe
or adjustments to the airfoil can have adverse effects on pitch stability.
Reflex bridles provide pitch stability at low angles of attack. Correct attachment and adjustment of the reflex
bridles is essential for maximum stability.
A string line can be used to check the reflex bridles are correct. The line should be firmly stretched between
the reflex bridle attachment eyelet on corresponding battens on the right and left side of the glider. Check the
measurement from the string line to the top of the keel.
The glider should be standing on the control
frame. It is important to support the keel off the ground from the rear flying wire attachment point
otherwise the keel will flex and the measurements will be incorrect.
String tension and measurement technique will cause variations of +/- 10 mm. This tolerance should be
considered when checking against the chart below.
Summary of Contents for FUN 160
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