' I regret that as Dan says, there is very little safety margin with my 12 foot design.'

I tend to feel the same way about the 10' machines we've been building for the last couple years with 1" x 2" block magnets.  Most are fine but there have been a couple burnouts and the safety factor is small.

 ' Nowadays I actually use 16 inch magnet rotors and thicker wire.  Bigger magnets work well as a fix for the existing rotor size but are a relatively expensive solution compared to making the rotors/stator bigger.'

I'm not convinced that its a more expensive solution actually.  There is a compromise there.  Larger magnets make for a smaller/lighter weight machine.  Less steel, less resin, less copper, less time to manufacture (slightly) - but  yes, higher magnet cost.

There was also the issue of trying to save time/cost using existing molds - magnet rotors that are already cut out etc...

 ' And a bigger stator has more surface area for cooling.'

That is true, although I think we cut the heat in stator in half which is a big safety factor.

'There are plenty of things to go wrong with the axial flux turbines (as with all small windmills) especially in a tropical climate where corrosion of metal and electrics, saturation and rotting of timber, high temperature and humidity make for challenging conditions.  It's going to be interesting to watch blueEnergy get on top of these issues. '

Yes, the climate is tough there.  They get more corrosion in 1 year than we do in 20 I think.

 'Dan and his crew certainly gave them a leg up in the process.'

I hope so.  Another week or two would've been great.  I am glad though that they plan to come here in the summer (some of them).

'I have had a lot of new ideas since the 2005 edition of my plans (How to Build a Wind Turbine) and I am trying to get them into print.  The problem is to get the process finished.  I am preparing a 'wind turbine recipe book' for publication this year which will have my updated design ideas.  Using these ideas in courses helps me find out what works for people.  Its mainly about making the machines easier to build rather than improving their performance at all.  And keeping well within the envelope so as to prevent burnouts!'