Ver 2.oh Generator...
Blades, tail and flying ...
Over the last month the "Twin Stepper Gens" have been removed and forwarded to another home.
This has given me incentive to resume work on the Permanent Magnet Gen posted earlier.
The hub for the blades came out of the sand fairly true and was quickly machined just enough to get a sense of "Flat" while retaining the scribed lines and hole placement markers.
The idea of carving the blades seemed far more intimidating for lack of experience and required a week of avoidance before I settled down to get it done.
The worst was trying to visualize the "Twist, taper and air foil" between Hugh Piggott's website and Otherpower.com I eventually had it clear enough in my mind that I muddled through it ok... Though they have yet to spin in the wind so I guess it may be best to hold judgement for now.
The intention with this particular V2 Gen is to broaden the scope of basic skills for future mills. The idea of making a wooden 3 blade rotor is a significant leap over the pre-formed plastic blades that were used on the original Stepper Gens.
The PM Gen unit is really just a point of reference since it was tested at various speeds with accurate load data in the last installment, so the blades are what are being assessed in this section.
Provided that they perform reasonably well, I'm leaning toward a dedicated CNC Blade mill with a capacity of machining a 5ft blade... Certainly I'm getting ahead of myself, but it is nice to look a little further down the road.
The test fit came out surprisingly well on the second try...
Foolishly I cut the root ends that mount on the hub at 45 degrees per side rather than 60 degrees initially.
I had anticipated such a snafu and still had enough material left on the mounting end to re-cut properly.
The blades had 2 coats of varathane, dried assembled onto the hub, and the tips accented.
The motor mount assembly has been simplified by using some common 1/8th" band rather than the cast fixtures that were to bolt up from beneath.
This is far cleaner and easier, but mostly saved a trip into town for longer bolts to fasten from the bottom.
The tail feather is test fit with the U-Bolts up through the frame.
Again the idea of keeping it simple has served me well.
The boom is made from a broken shovel handle, and the vane is a scrap of 1/4" mahogany sub-flooring.
The slot for the vane was ripped on a table saw.
Here is the painted, assembled unit just prior to mounting on the tower.
The rotor is approx 50" in diameter, with the tail boom 36" and the vane 12" by 24 (approx).
The diameter of the rotor, offset of the swivel post, length of the boom and area of the vane will have an impact on whether this points into the wind or is perpetually furled out of it...
Personally I'm hoping that it just points into the wind long enough that I can measure to see if the blades are able to achieve 700rpm in a reasonable wind...
The fact that I'm still using subjective terms like "reasonable wind" underscores the need of an anemeter, there is a chance that I could muddle along through at least one more mill version, but very soon, I hope to be actually making power rather than learning the basics.
As you can see it's just a week away from "Deer Season" by the pronounced fall like conditions.
The tilt-down tower is still holding-up well and represents a good investment in time to make as the installation went with a minimum of fuss.
It is a still cloudy day, but the generator is finally up and ready for the next gusty day that is generally the norm this time of year.
In actual fact I'm quite excited to see & hear how it works... the previous stepper gens made a whirring/whizzing sound with the plastic fan blades, while I'm hoping for a more bass thumping sound from these.
But with only a 4ft diameter I think I may be disappointed...
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