A return to model building and flying. Part 9

How to make a wing fixing exceedingly complicated

November 2004

At this point I am tempted to say, "Don't ask." I think my ambition exceeded practical bounds somewhere along the line

As I have stated before the original design called for a a removable wing held in place by rubber bands, an eminently simple, well tried and tested method. In the dim and distant past I remember handling soggy oil soaked rubber bands on R/C models, In the not quite so distant past I got used to the luxury of wing fixing bolts on C/L models. I suppose this is why I was reluctant to use the band method on this model.

What I had not taken into account was the physical small size of the model, and the fact that it had not been designed for this sort of fixing from the very beginning. Retro fitting anything is usually never easy, or elegant.

The rear fixing was reasonably strait forward, and allowed me to use two bolts.

rear wing fixing

The front fixing was a nightmare. There was virtually no room to get a single bolt in place between the wing and the bulkhead, let alone two bolts. Two was also impractical due to the shape of the fuselage. To incorporate such a feature would have needed a major redesign of the fuselage, something that was obviously impractical.

After a lot of carving and filing a groove in the leading edge, one thing I hope does not come back to haunt me, I manged to get it all together. And utter a great big sigh of relief.

wing front fixing 1 wing fixing 2

The last picture shows belcrank ready for fitting, and the over complicated method I had to adopt to make sure the front mount does not collapse when the screw is tightened.

belcrank and wing fixing



WHEELS

Fitting the wheels in place, I thought, would be an easy task; not so, it turned out.

wheel retainerThe hubs had quite large bore axle hole, which requred sleeving, then I had to fine some large washers to act as retainers. The solution was to use common brass clothing eyeletts, the sort available at any haberdashery.

Something strange happened to the hubs after I soldered the wheels into place, they both tightened up considerably. Now my first thought was that the plastic had partially melted.

Usually in these circustances spinning the wheels on an drill with some lubrication will free them up. Not so in this case. They stubbornly refuse to do anything of the sort. In an act of desperation, I even ran them at a few thousand rpm on a bench grinder, after which they spun freely for a few seconds, then tighten up again.

It looks like an unsoldering job is due to try and find out what is causing the problem.


And lastly a picture of the state of play to date.

airframe



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