"larry" wrote
Now, fix the real problem. The pitch of each blade must be identical!
The pitch is the angle of twist from the leading edge to the trailing edge
of the blade. Most blades are mounted with an "H" shaped bracket and can
be adjusted by slightly twisting the bracket at the short section between
the two outside bars of the H.

Those look like they're cast and won't take much tweaking before breaking.
But I will investigate it with the light bulb thing. Sounds like a simple
solution to a complex problem.

Kind of against my nature.

Steve