sorry to correct you in this point ... and even so late ..
(me: working in that industry in germany, and I'm working hands-on as well as at the desk - offshore/onshore - development & fixing).
The Growian was a pitch regulated, 100m rotor diameter, two blade, downwind turbine with steel body fiber glas reinforced profile rotor blades and an asynchronous generator.
The growian had only 420 productive hrs.
pitch & cone regulated, single profile steel only blades - downwind - asynchronous generator
The smith putnam had 1000 productive hrs.
The german wind turbine development took their ideas mostly from the danish designs of the 80s - many turbines were build under OEM contracts
The "modern" wind turbine of the revolution:
Three blades - stall regulated - asynchronous generator - up wind type - with "tip brake" - fiber glass reinforced blades
the blades tip could be rotated 90Â by a spring loaded mechanism triggered by the turbine control system.
the historic main companies active in Germany
- Nordtank (later part of Vestas) (DK)
- Micon (later part of Vestas) (DK)
- later NEG Micon (later part of Vestas) (DK)
- AN Bonus (DK) (now Siemens(DE))
- Nordex (DE)
- Adler/Koester (DE)
- Jacobs (later part of REpower) (DE)
- HSW (later part of REpower) (DE)
- Aerodyn (DE)
- Lagerwey (NL)
And some even had a wind driven yawing system like the AeroMANn a two blade upwind turbine .. with a mere 33 kW.
The "current" motern wind turbine:
pitch regulated - Doubly fed generator or full converter - three blade - upwind windturbine with fiber glass reinforced blades - 100+ m rotor diameter - 2-3 Megawatt.
The current three blade state of the art turbine has much more in common with the danes simple turbines than with the Growian.
Growian and Smith-Putnam are quite well comparable as they share certain similar design features as well as their structural mode of failiure- just that Growian was shutdown before it would've thrown a blade.
But when you'd want to take a look at the history of the small steps you can read the "Windkraftanlagen - Grundlagen, Technik, Einsatz, Wirtschaftlichkeit"
from Erich Hau.
You will then realize that virtually no research from the Growian could be used on that small step path.
(Remark: we do not mill with these turbines, we just visit the "Windmuehle" or the "Muehle" which does not mill - normally)