Sail Tension Markers For more twist, rotate up For less twist, rotate down Wing Twist Adjustment UP DO WN Figure 5-38. Carefully zipping bag with minimum stress by tucking  in wires and organizing components. Figure 5-39. Left hand wing tip twist adjustment shown without  sail. Wings are designed to fly straight with a range of trim speeds  determined by the manufacturer. If the wing does not fly  straight or trim to the manufacturer’s specifications, it must  be tuned to fly properly. Any wing adjustment can change the  handling and stability characteristics of the wing. Each wing  is unique and the tuning procedures are unique for each wing.  It is very important to follow the specific tuning procedures  in the POH/AFM for the specific wing. The following are  general guidelines to understand the tuning process. Wings may turn to the right or left (depending on which way  the propeller turns) at high power settings because of the  turning effect described earlier in the aerodynamics section.  If it does not fly straight for cruising flight, visually examine  for any asymmetric right and left features on the wing  before making any adjustments. Look for symmetry in the  twist angle. Inspect the leading edge for any discontinuities,  bumps, or an irregular leading edge stiffener. Ensure the  pockets are zippered and symmetrical on both sides. Ensure  the reflex lines are clear, straight, and routed properly. Check  the battens to ensure the right and left match (do not make  any adjustments in the battens initially because reflex may  have been added at the factory initially for tuning), and  ensure the battens match the manufacturer’s batten pattern.  Check the batten tension on both sides and the leading edge  tension to ensure it is symmetrical. If it is a used wing just  acquired, research the history of the wing to see what might  have happened which would cause it to not fly straight. For  new wings, contact the manufacturer for advice.  If these checks do not make the wing fly straight, then  adjust the twist in the wing according to the manufacturer’s  instructions. More twist on one side decreases angle of attack,  produces less lift, and will drop the wing, which makes it turn  in the direction where more twist was added. For example,  with an unwanted left hand turn, either decrease the twist  on the left hand wing (increase angle of attack at the tip) or  increase the twist on the right hand wing (decrease the angle  of attack at the tip). Batten tension is one way of fixing very mild turns. Increasing  the batten tension at the tips especially decreases twist and  raises the wing. For normal mild turns, most wings have an  adjustment at the tip where you can rotate the wing tip around  the leading edge. This is the easiest and most effective wing  twist adjustment.  [Figure 5-39]  For some models, reflex at the  root can be adjusted on a side to adjust a significant turn. More  reflex on a side means wing up, similar to reducing twist in a  wing. As emphasized above, the POH for each manufacturer  must be used for adjusting twist for wing tuning.  Adjusting the tension on the leading edge is another method  of adjusting the wing twist. However, different wings will  react differently when tension is adjusted, so the POH must  be followed for a particular wing. Some manufacturers do  not suggest adjusting sail tension to adjust twist, but require  equal tension with other adjustments to remedy an unwanted  turn. For those wings utilizing asymmetrical sail tension to  adjust twist, the following information is provided. Adjusting  sail tension is most effective on slower wings with lots of  twist. Adjusting sail tension affects some high performance  wings differently, making it necessary to consult the POH.  However, on most wings, increasing sail tension at the tip  increases leading edge flex, resulting in more twist.  Most wings allow the hang point attachment to move forward  to increase trim speed and back to decrease trim speed.  If there is a situation where the hang point is at the most  forward position and the wing trims below the manufacturer   Wing Tuning  Tuning the Wing To Fly Straight   Tuning the Wing To Fly Slower or Faster  5-14