Yes it's all in the design.
There is very little I can agree on here.
Your costs are through the roof compared to mine. I built 2 x 4 meter units for the cost of your black box. Either one will probably out perform your latest 3.2m unit.
They have run for 4 years or so, and only some magnet rot to show for it. They run in winds I can hardly feel on my cheek, and in low winds will certainly whip a 3.2 and in high winds I try to keep them less then 2.5kw.
With a stator change and a boost converter (or cap bank), they would sustain 3kw or more without stalling the blades too much at all (curves match much better with 16mph cut in)
There is no extra cost, little/cheap extra complexity..... just simple stuff.
If we were to look at a single swept area as a maxima, then your arguments would be more justified. I am happy though to not match perfectly through the range, and just make it bigger if more power is required. Blades are near free, steel is cheap, a few more magnets (go to 16 per plate) is not terribly expensive ( I have heaps of 50x15 n50 and 50x12.5 n45).
But I also have a big milling machine, lathe, brake press (60 ton) guillotine etc. Making a gearbox is not the issue at all.... simple stuff even on a remote island...... but why would I try to stall the blades.
I also do a lot of power electronics, so that would not stop me either...... so I don't mean complexity as in I cant do it or understand it, I mean not needed if you just want to make real power.
There are lots of other ways too. The AWP up on the hill is 3.7m It can do easy 24-35 kwh per 24hrs. It is ferrite, no gearbox, radial (ok I rewired its 90 coils from 1kw to 2kw) It runs at 200-500 volts, transforms down and drives the battery bank (48v). 7 years without problem after we ironed out the manufacturing defects that the Africans built into it. ( poor electronics we rebuilt, poor fibreglass blades, and terrible tolerances in the machining and shocking yaw system and woeful furling ).... but it's redeeming feature is the armature reactance that stops it from burning up no matter how fast it runs.... so it runs flat out day after day 1000 feet above the surrounding land.... sort of built in load matching/limiting
So we don't need to do other than match the load as best we can in direct drive mode to make usable power..... unless we feel the urge to build the interesting stuff because we can, but it is not necessary, and adds cost/complexity to the unit. The gearbox is a useful idea, but it is still likely to introduce stall with neo magnets I would think, which can already stall a design without speed increase.
So, I don't expect to sway you at all.
I won't knock you for doing what you have done, quite the contrary, but I would not encourage anyone else to do it either.
If I were to use a gearbox, it would likely be on an induction conversion, but even that smacks of shooting yourself in the foot just to test out the first aid kit
As you said it is all in the design. For me good design is doing the required job with the simplest fool proof system. The wind takes no prisoners over here.
................oztules
Edit. I have never understood why people on these boards don't use transformers in their design. Microwaves are cheap (free even here) and plentiful, and can provide mountains of laminates to build very powerful transformers...... but no one else seems to do it. Even quiet day/ heavy weather tap changing would yield surprising performance differences..... including your headroom. It is easy to double the current in the bank while decreasing the current in the stator on windy days. The AWP would never see more than about 7 or 8 amps in the stator while delivering 38 or more amps@55v.
The stator from the AWP:
Ferrites in the AWP:
Another ferrite unit I built only 1.5kw or so
