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105. Back on Task


We weren’t expecting discrepancies in the wing struts, so it was a bit of a worry when it looked as if one of them might have been about 10mm too short.

But as so often with these things, when you sleep on it, things seem to sort themselves out, and when we checked with the clinometer this morning, all was well, and within acceptable limits.


Much of the rest of the day was spent on the other essential task of the week – sorting out the lengths of the cables in the aileron control.

The control stick is mounted on the torque tube under the fuselage. The warp lever fixed to the front of the torque tube has cables running from it out via pulleys in the lower wings to the underside of the lower ailerons. These are connected to the upper ailerons by a pair of lightweight cables , and then there’s a cable connecting the two upper cables to complete the circuit.

Obviously we had to have the wings fitted to the fuselage to measure all the various lengths, and so we set about doing the necessary measurements. But before you can do that, you have to drill a hole in the lower wing inboard end ribs through which the cable runs, and it was necessary to find the right position by trial and error; the cable mustn’t touch anything in the fuselage or wings on its way through. In fact, there was no single position for the hole that did all of this, and we decided to fit an additional fairlead to try and stop the cable running on at least some of the internal wing fittings. Even then, it took two goes before we had the hole in the end of the wing in the right place.

Next little complication was the vertical cables between upper and lower ailerons. The problem here is that they don’t have any sort of adjustment – you have to splice them at exactly the right length. Get it wrong, and it could have a considerable effect on the aircraft’s handling. Thankfully, these can be done after the wings are covered, so we did the best we could using clamps and we’ll leave the final splicing until later.

We tried connecting the whole system, and – after one or two adjustments – it is really pretty good. The range of movement is reasonably small, but the control forces are acceptably light, we think, and it was the first time we could sit in the machine and try out all the controls at once. A great moment!

And then we had to tidy up for the  red letter day on Thursday…


From → Building

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