Having asked a nearby builder to measure his stick friction using the string
and weight method- he reported that he couldn't - the stick fell over when
displaced !
This can't be strictly true as the system is the classical mechanics
"conditionally stable" setup, but it does point to a simple way of measuring
your stick friction without anything elaborate .
You merely displace the stick carefully sideways until it does fall.
Ignoring the niceties of sines and cosines it turns out that the the friction
force (at the hand) is given by the displacement achieved divided by the
length of the stick times the weight of one stick.
As you will not get as much as 6" extreme displacement this technique will
then work for friction up to around 1/3 of the stick weight of say 300 gm or
11oz.
It can easily be extended by increasing the stick weight articificially,
either by adding a weight on the top or within, taking due acccount of it not
being at the stick c.of.g.
Clearly some frills can be added to take account of the boss at the bottom
and a grip at the top, but these will be a constant if you just want to see
how your waggling and Brasso are working. The sticks must be accurately
parallel too.
I would be grateful for any measurements taken with and without the wings in
place, as I can't put the wings on mine in its hibernation habitat. Also
whether the bearings throughout are greased or oiled.
A final thought - the autopilot servo could in principle be used to do the
waggling either by direct electrical input or a gps input in simulation mode.
However one might have to worry about the continous rating limit.
Graham Clarke G-EMIN
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