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

This fact sheet applies to tail planes manufactured at Probuild. Which have a Gator spar system ready fitted in to the tail cores. However, the general principles remain the same no mater what aircraft you are building.

Tail Installation

Install the Gator plug-in adjustable tail set.

1. Before the tail plane is glued in to the fuz the Gator plug-in adjustable tail set must be fitted first. Tail planes manufactured at Probuild come with the phenolic tubes ready installed.

2. Using 1/8" balsa or 1.5mm (1/16" lite ply, cut out the airfoil section of the tail for the 'Root Ribs' of the centre section.
3. Mark out the positions of the spar and the adjuster assembly on the ribs, taking care to position the adjuster to just fit in between the balsa sheeting on the tail half's.
4. The rib sections will require some reinforcement, 3mm (1/8") lite ply where the adjuster assembly is to be positioned.

The centre tail section will need to be shortened on both sides to compensate for the thickness of the root ribs, other wise the leading/trailing edges will not match up to the centre section.

5. Glue the ribs to the tail and centre section, using white glue. When dry sand ribs flush with balsa sheeting.
6. At this stage the tail centre section can be glass/epoxy skinned before it is glued in the fuz.
7. To prevent the tail half's coming apart mid flight, the ends of the alloy spar are bolted though the balsa skin and the phenolic tube, with two DUB571 4-40 x 1/2" Cap Head Screws. One at ether end. Where the bolt protrudes through the balsa skin, this area is re-enforced with 1/16" ply 20mmx20mm set in to and flush with the balsa skin. (The spar tube ends will need re-enforced with hardwood then taped out to 4-40 to accommodate the bolts)

Installing the tail in the Fuz

1. Mark out the centre line for the tail plane on both sides of the fuz at the correct height for you aircraft. This should normally be at 0 deg incidence. (Check the correct incidence for you aircraft)
2. Position the centre section of the tail plane on the centre line 10mm back from he rudder hinge line, then draw around the airfoil section on the fuz.

3. Cut out the section using a dremel and fine file leaving a 1mm - 1.5mm gap all round the tail section.
4. At this stage the insides of the tail cut out can be re-enforced with glass/nomex for extra strength when the tail is fitted.
5. Insert the complete tail assembly and hold in position using 1.5mm balsa spacers.
6. Align the tail plane on the centre line of the fuz making sure that the tail tips AT THE HINGE LINE are at equal distance from the fin tip (the fin will be at 90deg to the tail plane) and at an equal distance from the centre line of the fuz at the nose.

7. Using Chemie Technique 101 epoxy or similar mix with some micro fibres to a stiff consistency, then pack the gap between the tail section and the fuz with this glue, when packed with epoxy re-align the tail as above making sure the tail is aligned squarely with the fuz. Smooth off square with the fuz and leave to set.

It is a good idea to allow yourself plenty of time for this operation, and double check, as mistakes cannot be rectified easily when set.

8. When set the joint between the tail and fuz can now be filled using epoxy and faring compound, then sanded smooth.

The finished plug-in tail plane

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.