2006-12-14 #1

Discus Upgrade

J'ai trouvé un sujet dans les forums du OzReport que j'avais repéré il y a quelques temps. Je le publie ici pour référence :) Il s'agit de modifications à faire sur le Discus afin d'améliorer ces performances (en maneuvrabilité vraisemblablement).

Le sujet est ici : http://ozreport.com/forum/viewtopic.php?t=486 et la doc de l'upgrade ci-dessous. A noter qu'il faut un nouveau jeu de cables pour la modif complète.

UPGRADING THE PERFORMANCE AND HANDLING OF THE DISCUS

The Discus is a very stable and easy to fly wing. It has been made this way so that pilots can transition to it comfortably from single surface wings without any 'surprise' flying characteristics.

The Discus however can be 'upgraded' in performance and handling (quicker response) by adjusting a few components and replacing the side wires. Note, making any change outside of these guidelines will result in the Discus being outside of its tested stability range. As with ALL hang gliders, make sure that your glider is within its tested specifications at all times.

These upgrades should be done one step at a time, so the pilot can become accustomed to the newness of the glider performance and handling characteristics. Also, if any change you make is undesirable to you, you'll know exactly what to return to stock configuration.

In some instances, it might be best if your dealer does these changes for you. If you are not familiar with working on hang gliders, we recommend that you take your glider to your dealer or qualified glider mechanic to have this work performed.

With these changes to the glider, the pilot can expect lighter handling and better performance. The glider will have some tendencies to become less directionally or roll stable. The pilot needs to be completely comfortable with the Discus in its stock configuration before adjusting the glider. These steps are designed to allow the pilot to become comfortable while growing into the new characteristics of the glider slowly. The pilot should fly the glider for many hours before going on to the next step in tuning up their Discus.

STEP 1. WASHOUT TUBE ADJUSTMENT (Sprogs)

Lower the washout tubes 2 full turns. You need to remove the washout support cable from the top of the leading edge (very simple safety ring removal). This can be done with the glider set up but is most easily done with the glider broken down or at least with glider on control frame and wings folded. Once you have the cable support detached turn the washout tube clockwise (screwing the washout tube IN toward the leading edge) 2 full turns (720 degrees of rotation) and reattach the cable. Do not adjust this tube inward more than 2 full turns.

This Step has the least effect on the glider and may not be noticeable at first but as other tuning is implemented it will show up more.

STEP 2. LEADING EDGE ADJUSTMENT

Twist the aft leading edges down. This is most easily done with the glider broken completely down in the bag. Roll the glider so the control frame is under the glider (KINGPOST UP). Unroll the sail, detach the sail at the aft leading edge, you need to slide the sail up the leading edge a bit. Open and look inside the washout tube zipper. You will see where the aft leading edge steps up to a larger diameter tube, there is a crescent shaped plastic spacer (much like the end of the leading edge where the tip wand plugs in). It is fixed in position with a small set screw. There are five marks on the crescent spacer, the screw corresponds with one in the middle of the range. Remove the set screw, twist the plastic piece up toward the top of the tube two marks on the plastic spacer with a large pair of channel locks or pliers. Put set screw back through same hole in aluminum leading edge to secure the plastic spacer. This moves the aft leading edge forward and down, tightens the sail and removes some twist from the out-board wing. Of course, do the same to both sides and reattach sail at aft leading edge.

This has a greater effect on the glider, pilot should notice lighter handling and increased performance.

STEP 3. REPLACE THE SIDE WIRES ON THE GLIDER

Flying and Top side wire replacement. You need a new set of lower side flying cables and a new upper side-to-side cable. The easiest way to change these wires is to have the wings completely folded in on the glider with the glider sitting on the control frame. Fold the assembled control frame under the wing so that the glider is laying flat on the ground (kingpost up) with the control frame raked behind the glider (under the keel). Take your time and make sure things are routed correctly. You can easily access the wire attachments on the crossbar through the crossbar/leading edge access zipper. We recommend doing one side at a time so you have a reference on the other side in case you get confused while putting it back together.

This again will improve handling and performance slightly.