This Fact Sheet is primarily aimed at the newcomer to Building R/C Model Aircraft.

This fact sheet applies to Wings manufactured at Probuild. However, the general principles remain the same no mater what aircraft you are building that utilises a one-piece wing.

The following is a recommendation on how best to join such wings.

Wing reinforcing should be adhered to as follows, it is imperative not to try and save weight on one small central reinforcing layer of cloth. The wing will not survive long term; a stress point at the junction where the fuselage side meets the wing will end up causing the wing to snap! Using the 3 layers of 80g-glass cloth in the method shown has proved 100% reliable.

1. Before joining the wing make sure that all cut-outs/holes for the aileron servos and retracts units/servo (if required) have been done.
2. The wing should be set up on a flat surface with the wing tips parallel to each other. (A wing incidence meter can be used for this operation) Any deviation in wing panels should be taken out at the wing root, maximum error 2mm. There are a number of ways to make sure that the wing tips remain parallel during this operation. The wing can be sandwiched in their shuts (Foam outer cores) and set up on a flat surface. An incidence meter or level is then used on the top of each shut at the tips to make sure the wing tips are parallel. Alternatively you can make a couple of ply templates and fix them to the centre lines of the wing tips, the depth of the template should be equal to the dihedral of each wing panel from the wing tip. An incidence meter or level can be used across the top of each template to check the tips for being parallel with each other.

3. Check for correct dihedral and make sure the wing panel roots meet flush with each other in the middle with no gaps.
4. The two panels are joined using epoxy, making sure that the wing tips are still parallel
5. With the wing joined ensure that all parts of the joint are sealed.
6. Apply dope to the wing surface where you are going to place the glass cloth. The coat of dope need not be thick, just sufficient to seal the surface of the balsa skin.
7. When the dope is dry, lightly sand with some 360 wet & dry used dry.
8. Remove all dust particles from the wing and wet out the surface with epoxy.
9. Cut out the pieces of 80g glass cloth to the dimensions shown for both sides of the wing. If using retracts, don't for get to allow for taking largest piece of cloth around the retract fixing points. (For extra strength the shortest length can be cut from 93g carbon fibre)
10. Carefully place the longest length of cloth (1) on the wing surface and stipple with a brush to wet out the cloth; the cloth becomes transparent when wetted out.
11. The second longest piece of cloth (2) is then placed on top of the first layer of cloth; there should be little need for any additional epoxy to wet out the second layer of cloth.
12. The shortest layer of cloth (3) can be applied when the second layer is wetted out.
13. The process is repeated for the other side of the wing.

14. When the epoxy has set it can be lightly cut back with 240 wet & dry used dry to just to remove any surface roughness.
15. A weave filling layer of epoxy and fairing compound can be applied with an old credit card.
16. Once dry the entire surface can be cut back to a smooth surface in readiness for your favourite finishing process.

Recommended Materials: -

1. Cherbourge 101 Epoxy Resin
2. 80g Plain Weave Cloth
3. Fairing Compound
4. Latex Gloves

All these materials are stocked and can be purchased at Probuild.

Manufacturing facility

Here at Probuild we can manufacture on the premises any wing / tail section to your specifications A great deal of time and preparation is spent on producing wing cores. The cores are cut on a CNC foam cutter, which has been set up by lasers for greater accuracy. The skins are applied with epoxy resin using a vacuum bag process to provide an even pressure of around 2000lbs on each panel during the curing procedure. This helps tremendously with the bonding of the skins and makes for a stronger and lighter, wing, tail and rudder panel. The whole of the curing process is carried out on an engineer's surface table, which is totally flat and weighs around 3/4 ton. After trimming the wing panels they are then checked with a vertical vernier gauge to confirm accuracy before shipping to you the customer.

An additional bonus to this system allows all of the aileron and elevators to be faced and Kevlar hinged prior to the skins being attached to the core. A reduction in building time is a trade off to you the builder as well as having a more accurate wing or tail panel.

The control surfaces are made integrally when the panel is made, therefore accuracy is also increased. Why do the other companies use a press? Simply time & money. It takes many hours longer to vac a wing & it is more expensive in consumables, but the end result is a much stronger lighter wing, Christophe also uses his own built lighter wing rather than a factory unit.