I noticed that there is one large nut at the rear holding the magnet / stator assembly on.

Have you locked this nut in such a way that it can never unscrew against the turning direction? Left hand and right hand threads against turning diection etc.  You should know what I mean.

Otherwise well done and keep us informed about power output etc,

Take a close look at the nuts that hold the coil casting on. Can they unscrew themselves?

I would hate to all that beautiful work destroyed because not enough attention was paid to these crucial features.

Keep checking the whole machine - this the good thing about posting photographs.

Structures like this are strong in compression and tension, but not in bending or torsion.  Forces should be along the length of at least one straight piece, not at right angles to a single support.  Single supports - especially thin ones - should not be twisted.  Joints that may be pushed in more than one direction should be supported in at least two directions in two-D, three directions in three-D, so the supports can divide the load such that they're only loaded in compression or tension.  The members should be connected to form triangles and pyramids, not squares or arms - especially arms with bends.

So think of them as if they had springy flexible joints where they make a corner or are fastened to another member.  How do they bend?

In these designs you have a star of thin radial strips, with allthread at right angles on their ends, supporting a disk that is TWISTED by the main load.  OOPS!

 - When under a torque load the strips are in torsion and act like springs, while the allthread rods act like levers.  The twisting stator is pulled toward the downwind rotor while enormous leverage on the allthread rods tries to fracture the stator where they are attached to it.

 - When loaded along the axis, the strips act like springs in bending, allowing the stator to move in either direction and contact one rotor or the other.  Further, there will be some frequency where it resonates.  Vibration at this frequency will "pump up" a mechanical oscillation until it bounces between the rotors and friction there takes out vibrational energy faster than it is added.  If this frequency happens to match the "singing" at some RPM you're toast.

Seems to me there are a couple things that could be done to fix this.

First:  Stiffen the supports:  Weld on a support against along-axis bending and torsion, making them into a T or L cross-section.  They can be made ever stronger by making the strip and/or the support roughly triangular - wider at the hub than near the attachment of the allthreads.  Alternatively you could use three rods or angle-irons to form a thin pyramid, being sure that they don't all have their planes parallel if they're sheet metal.

You have done a nice job in both design and workmanship. You have given the stator lots of room for air cooling.

I tend to agree with tecker and flux concerning the strenght of the stator mounts.

Check out the Dan's 17 ft. designs old and new on this forum. Reinforced stator mounts on the new design.

I have reinforced my stator mounts to try to strengthen rotational torque. Hope these pics help.
lglagasse

pic # 82 is my original design.

  but now i am going to rethink on how to make it good.real good.
  as yet i havent had a mill running .so know nuthing about the power out
 or torque made as it generates.

  so its good i am thinging ahead to when its grunting a bit.
   it wasent meant to work two rotors and with the small studding honest..

  now to reply to each.
   spinning magnets .i to get envy  when looking at mills made here.
   but at least i am doing one myself now.
   maybe in the future you can build a nice gen sum ware.
   as your so interested maybe a friend or family member might want you to build one  
   for them.  who knows how lucky you might get.

   david hk.  yes your right spindly studding .
   stator isent made yet so just put it all together to check out how the shaft was                  
   fitting.
   the large nut on the back i might make into a castle nut.
   the back rotor wont ever fall off. as it pulls itself to the front one.

   thanks Andy. i just need make sure i wash my hands real good.
   before going to bed at night.

 hi lglagasse.  working on a good way to hold the stator tight.
    will post a pic of how i modify it. and ask for comments as to its
    strength etc

    hi tecker like every one else said .to spindly.  yes i agree .

   ungrounded -l-rod.
  a verry good page you posted.
   verry interesting reading. it made me do a bit of new type logic thinking.
    i have tried running it at 800 rpm in the lathe and it was verry calm.
    so the thing wasent under load. and had no prop. but seamed ok.

   hi flux as you also said  . i know a thing works ok on the bench but in real
   conditions its a different  story.
   am a working on it boss.
   now flux i have been testing coils .
   and with the info you gave me i got my lathe running at 220 rpm.
   my cut in speed.
    two strands 16awg and around 55 turns. it was spot on .
   or as thay say here right in the ball park.
    also tried the 14awg . it was over valtage at 55 turns.
    so would have ended up with skiny coils using the 14awg.
   so again you give sum great advice.
   and i put it to the test and was great spot on mate.
   hope i havent forgot to do a reply to any one.

    and as i said in the beginning of the post .i will put sum pics of the shaft.
    should anyone be interested to make comments on it.
    but you need to see the pics first .
    the thread at both ends is metric. its 20mm.

    also made a spacer to fit between the rotors .
    so at 1/2" min air gap i can put a spacer in to make it as wide as i need.
   two bits at the front hold the prop with a  20mm nut on each.
    also three bits studding go through the prop aswell to lock every thing tight .
    the nose cone has a 20mm threaded hole in the back so just screws on.

    i might have a go making castle nuts. 20mm is hard to find lock nuts.
   now to post a few pics.
   if you see any probs with shaft .dont hold back .
   well no one held back saying about the skinny bolts holding the stator.lol.











  just saw a pic with a white painted rotor.