Some builders have found that the "dead reckoning" method of attaching
the bolts for the quick release bracket on the spars, suggested in the
manual, can end up with misalignments when the wings are slotted in. It
is probably caused by distortion of the cockpit module brackets which are
none too solid at this stage. This makes necessary wedge shaped spacers,
can give relative movement of the surfaces, and even sloppiness.
It is also a nuisance to have to test the result outside (with most
builders' accommodation) and to have two people.
Life can be made much easier by making up dummy wing spar root sections.
You don't have to hack them out of 35mm thick material, just make a
sandwich of two 5mm ply templates (by drawing round the wing roots), and
separate them with 1" blockboard just around the hole positions, perhaps
adding a central stiffener.
Drilling holes guided by the spar bushes, gives accurate replicas, which
can be easily inserted into the cockpit module, and the required
positions for the wing quick release clamp pivot bolts determined.
Drilling the bolt holes on a drill stand, then gives accurate
perpendicular holes, which after the mechanism is checked, can be
transferred to the real spar by clamping the two together, with the
retaining pins through both.
Another bonus is that you can see exactly where the spars lie inside the
cockpit module, (again inside in the warm), and build in the "tank
expansion limiters" and also hardwood guides, which in my opinion are
necessary to make subsequent insertion an easy operation, less likely to
damage things on the way in.
graham ..doubleton (No.83)
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