RE: 1:3.7 Pilatus PC21 turboprop build
Little done on the hinging today. Started on the ailerons and rudder, the system used is wire through hinge points and utilises three substantial hinges on the ailerons and two on the rudder. Fitting the hinges to the control surface was simple, and a little sanding opened up the pre-cut slots, making a slot in the wing was another task altogether, as the hinges are very thick fibre glass board the holes required are quite large, after drilling with a 5mm drill bit into the recess in the wing trailing edge I slowly worked the holes into a elongated slot using a coarse round file. the wood running behind the wing recess is very hard and took some time to achieve the final satisfactory openings.
Once done the hinges were test fitted and then finally assembled for fist fixing. The manual suggests around 1.2-1.5mm gap around the aileron to wing surface so to achieve a consistent gap I wrapped a couple of rubber bands around the aileron, these gave the desired gap and held the aileron in the correct place all round the gapped mating surfaces.
Once fixed I noticed the wire retaining pin was very sloppy in the hinge holes, allowing a fair amount of unwanted slack, on measuring the wire pin it showed a diameter of 1.8mm, I tried some 2mm in its place and the result is slack free and rock solid, I guess there must be a slight tolerance issue in the wire or hole cutting but at least the right sized wire worked out OK.
Hinged the rudder in the same fashion using rubber bands, and applied aeropoxy to the inside surface of the hinge plate as I was able to get inside via the servo cut-out to apply the epoxy.
marcs