Unlike the stabs, the Andes wings are of the foam core variety. I’m not sure why there is a mix of construction techniques but I’m sure there is a good reason.
Unfortunately, the wing tips suffered a little damage during transit. The wing tips on this model are quite pointed. Both wings come packed in bubble bags but a sharp wing tip makes short work of this. I’ve suggested the factory looks at a better packing method to protect the tips during transit.
The belly pan had also come off the bottom wing during transit. This pan is just glued onto the film which in my opinion is inadequate. Later in the build I’ll detail the solution for belly pan attachment.
Whilst the above issues are disappointing, they are both reasonably easy to fix. Three of the four wing tips had contacted the end/corner of the packing box. The good thing about balsa is that it can be repaired or restored to its original shape with water quite successfully. One needs to inject the water with a needle/syringe, allow to soak into the wood and then heated with a covering iron. The process may need to be repeated a couple of times to remove the dent or ding.
The belly pan was glued to the bottom wing but came off during shipping. The adhesive didn’t stick to the film properly mainly because of the gap between the pan and wing section. Some adhesive was left on the film but most was on the flange of the belly pan. The adhesive left on the film was carefully removed with a sharp scalpel. The adhesive on the belly pan was sanded off with a drum sander in the Dremel.
As with the stabs, Radio South CA hinges will be used. The hinges are cut in half (1/2”) and five will be used on each aileron. The centre of each hinge is marked on the wings and Ailerons first. Then all the slots were cut using a sharp scalpel and the Tettra hinge guide. This hinge guide is the bees knees. I don’t think Tettra is still around but if you search the world you may still find one of these tools.
As was done with the stabs, the hinge was glued into either the wing or the aileron. This allows the aileron to be removed whilst finishing the control horns or linkages etc. Don’t forget to glue the surface in once those other jobs are done though... ;-) To help set the depth the hinge is set in, I mark the halfway mark on each hinge with a dot from a permanent marker.
Tip: When using the thin CA on the hinges, apply the drop of CA with the hinge at approximately 45°. This puts the control surface bevel at a rough horizontal position which helps stopping the CA running and creating a mess. The wing side isn’t beveled so when gluing this side just hold the wing vertically. Capillary tubing is also a big help getting the CA in to where it needs to go.
The Wing servos will be MKS HV69’s. Small ply servo trays were designed and cut from ply. These were set into the wings and glued with epoxy resin. A Starrett depth gauge is used to set the depth of the Servo plates into the wings.
The HV69 comes with rubber grommets as per most other servos. I found that with just two servo mounting screws, the lateral movement in the Servo was unacceptable for F3A. After a little head scratching, it was decided to hard mount each servo. A small delrin Bush or insert was made to eliminate the rubber grommets.
Servo extensions were not fitted at this stage as the receiver location was yet to be determined. Whilst on this subject, you would normally have four aileron extensions to connect up in a Bipe. PowerBox makes a product called One 4 Two which simplifies assembly and reduces the chance of error.
Linkages will be the same as the stabs with MKS 6mm Hubs, Carbon Servo Arms and 2.5mm Titanium links. Before making the linkages the control horns need to fitted. Hard point plates are pre-installed in each aileron but unlike with the elevators, the builder needs to determine the actual horn location because they are not recessed. Firstly mark out the extents of the hard point and determine the orientation of the control horn to get it in the middle of the hard point. We now know which side of the Servo the linkage will be on.
The MKS alloy hub and Carbon Servo arm needs to be fitted to the servo. This is so we can mark out the linkage path on a strip of masking tape next to the Servo. For the Ailerons 20mm Carbon Servo Arms will be used. This will ensure enough throw for snap rolls. The HV69 Servo is 13mm wide so 20mm - 6.5mm = 13.5mm. This is the distance out from the side of the Servo to be marked on the tape. I place a straight edge against the Servo side and the mark a line on the tape. Then mark out 13.5mm from this line and extend the line down onto the control horn hard point. The width of the Dual Axis Ball end needs to be allowed for. The 2.5mm variant is 4mm wide. A second line is marked 2mm inside the linkage centreline. This is where the edge of the control horn sits. I placed the front edge of the control horn right on the bevel. One can then mark and drill the screw holes for the horn. With the control horn mounted, the Dual Axis Ball ends can be fitted to the Servo and to the control horn. The aileron should be taped into neutral and servo arm also at neutral. The length of the titanium linkage can then be measured and manufactured. I cut the titanium to length with Dremel ceramic cut-off wheels and run a 2.5mm die over each end in the lathe. Only 10mm of thread is put on each end of the linkage. I also put a 2.5mm locking nut on one end of the linkage.
With all the servos mounted and linkages done, the aileron hinges can be glued in with CA. This finishes the wings.