The 4 aluminium wing joining tubes were placed into the wings during construction so at this stage I know they are all aligned correctly.
The only tubes that require trimming are the 2 at the rear. This is due to the inclusion of the aileron boxes. All the tubes were placed into the holes in the wing ribs, port and star board, and then the .8mm ply capping root ribs were placed over the ends of tubes. The rear tubes were then marked up with a fine pointed marker pen as close to the surface of the .8mm ply as possible. The rear tube fits up against the aileron box thus blanking the tube off and preventing the wooden wing joining dowel from working its way through the tube and into the wing. The 2 front tubes do not require trimming and just needed a short length of dowel gluing into the end of each tube, again to prevent the wing joining dowel from ending up inside the wing. The 2 rear tubes were then cut to length with a tube cutter, about 6mm was removed from each.
The only tubes that require trimming are the 2 at the rear. This is due to the inclusion of the aileron boxes. All the tubes were placed into the holes in the wing ribs, port and star board, and then the .8mm ply capping root ribs were placed over the ends of tubes. The rear tubes were then marked up with a fine pointed marker pen as close to the surface of the .8mm ply as possible. The rear tube fits up against the aileron box thus blanking the tube off and preventing the wooden wing joining dowel from working its way through the tube and into the wing. The 2 front tubes do not require trimming and just needed a short length of dowel gluing into the end of each tube, again to prevent the wing joining dowel from ending up inside the wing. The 2 rear tubes were then cut to length with a tube cutter, about 6mm was removed from each.
Wing joining tube marked up ready for cutting.
The 2 .8mm ply capping ribs needed to have a section cut from the front and rear ends to allow them to fit correctly over the centre section supports.
.8mm ply capping showing front cut-out.
.8mm ply capping showing rear cut-out.
Later there will be other cut-outs to the rear .8mm ply capping for the 'scale spars' to pass through. The rear 6mm ply mounting plate seen in the above picture has been rounded off to attain a good fit with the steel centre section mounting plate.
Having done the above preparatory work I could now get on with mounting the top wings...
Starting with the port wing it was time to see if the panels fit. This was the first time they had been offered up to the centre section struts and the first fit wasn't too bad. After opening up the slot in the balsa wood behind the ply mounting plate the wing panel dropped onto the rear steel centre section mounting plate and the panel was clamped in place with a small 'G' clamp.
Rear top wing clamped to mounting plate with 'G' clamp.
As previously mentioned the fit was made good to the rear mounting bracket by removing the corners to the rear ply wood plate. It was at this stage I could see that fitting the captive nuts for the rear fixing bolts was going to be a bit of a squeeze!! I'll worry about that later.
Front top wing clamped to centre section strut with 'G' clamp.
When both of the top wing panels had been correctly fitted to the centre section mounting brackets the panels were 'G' clamped to the front centre section strut complete with the 2 .8mm ply capping ribs, the 4 wing joining tubes and the 2 wooden wing joining dowels. Also included was a piece of stiff card placed in the centre of the 2 panels, this substituted the Solartex covering.
View of the top wing panels 'G' clamped in place.
Top wing panels 'G' clamped in place, underside.
Now comes the IMPORTANT part making absolutely sure that the wings are 'square'. Carefully measure from a know point on each wing panel, as close to the tip as possible, to the centre of the sternpost. When completely satisfied that BOTH measurements are identical give the 2 'G' clamps a final tighten to make sure the 2 wing panels stay firmly in place. Now we can mark the positions of the fixing holes onto the ply plates through the holes in the metal bracket and front strut.
Position of fixing holes marked on wing panels.
After these holes had been marked they were 'centre punched' and 'pilot' drilled. Each hole was then drilled out to the correct size to accept the captive nuts.
Fixing holes drilled in port top wing panel and ready to receive the captive nuts.
Front captive nuts in place, star board wing panel.
'Problem' captive nuts to the rear!
Now here's where the problem lay! Out of the 10 captive nuts all but 4 were easy to install. The 4 problem ones were those situated at the rear. 2 required a 'flat' to the side and the other 2 required countersinking into the ply mount so that the 'scale' rear spar could pass over them.
Rear captive nuts installed. They will be glued in place later.
And finally the top wing panels could be bolted onto the centre section. The bolts will get cut down later and the wing joining tubes still require gluing in place along with the captive nuts and the ply capping ribs.
Top wing panels bolted in place -
In the next post I'll be finishing off the top wing centre section.
Workshop Tip No.8
Whenever you need to drill a whole though hardwood or plywood it's a good idea to use a 'Centre Punch' to mark the position of the hole first. This process is referred to as a 'centre-pop' and is common practice when drilling holes through steel etc. This 'centre-pop' will stop the drill bit from wandering away from the position marked.
Workshop Tip No.9
When holes are drilled through wood the drill bit inevitably tears the wood around the hole on exit. To stop this happening place a piece of scrap wood underneath the hole being drilled. The drill bit passes through the work and into the scrap wood. When the scrap wood is removed it will reveal a clean, neat exit hole.To be continued...
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