Furling in addition to active pointing

[Wa]

hi folks,

thinking to myself how many times the impossible happens, (i know the answer to this)...

should i have a tail furling system in addition to a motor driven pointing system - ie., the electromechanical pointing system would point the mill steadily out of the wind as the high winds build, optimizing as much as possible, but if the unit just happens to get hit by lightning, makes it past the arrestors and the shielding, and fries my processor at that exact moment, the tail at a slightly higher wind speed (before blade breakup) would move the the rotor out of the wind mechanically -

can i assume this is not overkill? this will be a 16-20' mill

i have logged numerous transverse winds which wipe across the pasture at the same time most of my productive wind is present - if i could keep the mill from hunting and staggering at these times, build in a delay before the head rotates, i may be able to optimize things quite a bit - the question is,

what happens in terms of stress and turbulence at the tail when a transverse wind jams against it when the mill is locked into the "true" wind direction? most commercial units only have a nacelle, so this isn't an issue...

(if your wondering why i want to spend money on a pointing system, i happen to have the pieces and parts sitting around, and i am working on a motion control project with very similar software needs)

thoughts?

thanks,

warren

[Flux]

Not easy to combine both schemes, furling won't protect it while the nacelle is locked by the yaw motor. You might be able to use the equivalent of a furling system with no tail. if you could steer the bit where the tail ought to be with the servo, it would then furl to protect as long as the wind didn't change direction. That may give you time to take some other action.

Keep it simple is probably the best advice, it's  a big machine to loose control of.

[DanB]

that would be my thought too...

keep it simple.  Unless there is clearly a need for active controls, I would avoid them - and I think a machine that size doesnt need them.  I would question the reliability of active controls.  Consider - with a furling tail there is 1 moving part (the tail) - 1 pivot.  If its strong enough.. it shoud be quite reliable, there is very little to go wrong.  This would not be the case with an active electronic sort of thing...

But - if you think its fun and have a good idea perhaps you should go for it!

[elvin1949]

Good afternoon Warren

i have given this a lot of thought,and have to agree with DanB.I would furl BUT if you realy insist

on a pointing system keep it simple.

use an electric clutch to lock in the pointing system wired to use the same power supply as the electric's on the pointing system.

if anything fails it will release and let the furling system take over.

have fun be careful

later

elvin

[scoraigwind]

It seems as if you have a very turbulent site.  You might do better with a taller tower.  

Active controls are usually not a good idea but if you are an experienced control engineer or hobbyist and you have backup with good engineering knowhow then go for it.  It'll be fun.  I know of very complex systems that keep working with care.  It's a wasted effort from my point of view but loads of fun :-)