Hey Franz:
It's been quite a while since I have visited the Fieldlines forum and, perusing the various topics, I was especially interested to read the thread on your efforts with active pitch control. As it turns out, I worked on a v similar project a few years ago, similar in fact to the point of using a Makita cordless drill (looks like the same model you used), threaded rod/nut, a push/pull rod through the main shaft and a "spider" mechanism to keep the blades synchronized. I only proceeded however to a bench operational prototype (and crude compared to your device) but then came to the conclusion that I was not confident of building something sufficiently robust and reliable to put into actual operation - just too many potential failure modes I guess.
My project did differ from yours in that I utilized a micro-controller for the control function. It was the "PicAxe" type, a readily available, inexpensive and quite easy to program device (programmed in a type of Basic language). Although my motor control was simply full on/off, forwards or backwards via an "H bridge", the processor is easily capable of servo and PWM so would IMO would be ideal for this type of application. It would also offer good capability for things such as load control (MPPT?) and I'm now BTW working on a Picaxe based load control for my turbine.
Anyhow, I then turned attention to a passive type of pitch control using basically the same mechanicals as before but with fly weights attached to the blade shafts (with spring return) as the actuation mechanism (it's a 12 foot rotor BTW). I use 1" ball bearing pillowblocks for the blade shafts (two per shaft) with 1 1/2"ers for the main shaft. I have about a year now of cumulative operation and it has worked very well in all kinds of weather. I especially like the ability to run even unloaded without problems and the fact it does not slow down or stop in strong winds like a furling system would (and of course it is inherently more reliable than an active system).
I've read comments here that pitch control mechanisms are problematical in that a lot of maintenance is required but I have found no particular issues. I tend to build the stuff heavy (the pole top assembly is about 300 lbs total) and spray everything thoroughly with roller chain lube to avoid corrosion. I have no weather enclosure on the pitch control hardware and was afraid the bearings might seize or corrode but have not found it to be a problem, at least so far.
I also thought about using bevel gears as you did for the blade syncing but was unable to find anything suitable at decent cost (I think that's the better way of doing it). Would appreciate any ideas on a good NA source for such gears.
OK, enough for now but let me finish by saying what a great effort you have made, in both design and construction - certainly something to be proud of.