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Re: REFLECTOR: Bearing AD (Duane Swing)

In a message dated 2/3/99 1:06:48 AM Pacific Standard Time,
aegerter@dataway.ch writes:

> >>    Scott and I have been looking at the front bearing support and are
>  >> working on a solution.  One of the problems that any wide area washer 
> type
>  >> retainer or the reversal of the bearing in the holder, or even the
>  >> replacement of the countersink screws with standard flat head screws, is
>  >> that unless the control stick is restricted from being pulled back 
> further
>  >> than the full down elevator will allow (26 degrees) the possibility of a
>  >> total bearing failure or the attach aluminum bracket breaking as a
>  >> of constant flexing is still an issue.

There are bearings called dual row radial type that allow for a certain amount
of axial mis-alignment. They look to have two rows of captured ball bearings
in a race that is slightly concave. But the true problem as I see it in my
mind is that the control linkage travels in a slight arc from mid position
when moved anywhere from neutral. It would seem that some type of "scotch
yoke" assembly may allow the control lever arm to move in its necessary arc
while enabling the actual sliding mechanism to be free to prevent binding and
side loads from mis-alignment. This of course would only add about 10 more
items in a critical failure path, but may help to illustrate what the problem
may be. Up to now, we have been relying on the flexure of the aluminum tube to
"allow" the current system to work.

A scotch yoke type assembly would probably work best with another set of
bearing to stabilize the assembly. More weight and alignment problems. Sorry I
brought it up...

Dale Alexander
173 RG Gull-Wing