Introduction: Portable 12 Volt 17 Watt Wind Generator With Automatic Furling

I've just designed and built a practical, portable 12 Volt 17 Watt wind generator that is ideal (and appropriate) for setting up in campgrounds, parks, Earth Day exhibitions, research stations, and third world homesteads.

On "light breeze" days (5mph = 2.2m/s) when most wind generators are becalmed, this light-and-nimble unit reliably generates power, at charging levels, fully taking advantage of the erratic, gusting winds that are so common in near-ground conditions.

A 48VDC, 1,600 rpm brushed permanent magnet motor (#370-350-00 / PE24113G -from a medical centrifuge), with a standard keyed 5/16 inch diameter steel shaft, was used to serve as the generator. A shaft arbor, 3/8-24 right hand (Grainger Item# 3ZN05 / Dayton Item# 3ZN05) was fitted on the shaft, to use as a 12 Volt generator, @ 550 rpm, when turned clockwise. The motor, weighing in at just under 3 pounds, has permanently lubricated bearings, but is not weatherproof.

Note: If you plan to use a counter-clockwise set of blades, the timing of the "generator" brushes (2 carbon brushes) and internal commutator is such that the same amount of power (Amps and Volts) is also generated when turned counter-clockwise, but be aware that the shaft arbor manufacturer's suggestion as to "right-hand" and left-hand" thread pertains to motors only, and not wind generators, where the just the opposite thread is required.

Note that the Grainger Shaft Arbor requires a thin, soft metal shim inserted against the flat face of the standard keyed generator shaft, for the allen set screw (which has a knurled cup point) to bite into and firmly hold the arbor in place. I used 2 layers, fashioned from an aluminum beer can. Or, use a replacement allen set screw with a soft brass core. Also, two, 1-1/4" thin neoprene washers are needed to pad (and grip) the 1-1/4" steel washers that come with the shaft arbor. The original shaft arbor nut was also replaced, with a nut with a thicker profile, with a nylon locking core.

This portable wind generator is ideally suited for one 12 Volt, 21 Amp Hour sealed lead acid battery.

Granted, that's not much power, when compared to typical permanent, stationary wind generators. But this lean-and-mean device was designed to fill in the void, to reliably provide 12VDC power to remote, inaccessible locations.

Step 1: Stock High-Speed Blades for the Wind Generator:

After running the "generator" through a series of bench tests, it became obvious that my simple homemade PVC blades (300 max. rpm) would require a gear-up to properly turn the generator, an inefficient scheme that I was not wild about. And I was also reluctant to commit myself to a number of weekends designing, developing and refineing a set of small, lightweight blades that would achieve the necessary direct-drive speeds (550+ rpm), so I purchased a matched set of three Air-X Airfoil blades.

22-3/16 inches long, and designed for a clockwise rotation, when viewed from the front (shaft end), each with two .25" holes spaced at 23mm (25/32") on center. Having only about 1/4 the torque of the much larger Air-X generator, the 17 watt generator spins very easily, in the slightest of breezes.

The blades were mounted on a 5-3/4" diameter, 3/16" thick, ABS faceplate (blade hub), and carefully drilled out to handle either a 3-blade arrangement (as well as a 2-blade arrangement option). The blades were mounted to the backside of the faceplate (hub), to position the mass of the blades as close as possible to the shaft bearings.  After bolting the three blades to the ABS faceplate, the tip-to-tip distances of the blades were measured and the blades adjusted with light hand pressure until all three of the tip-to-tip distances were equal, then the blade bolts snugged down.

2 blades are more portable, being easier to stow, protect from damage, and transport, but tend to teeter on the generator shaft, in actual practice. But, after a series of tests, I decided on the 3-blade arrangement, as it provided better performance in low wind conditions (actually typical for many locations).

I fashioned a discarded (actually I'm a hopeless pack rat) thick-walled plastic easter egg ornament into an aerodynamic parabolic plastic nose for the hub, and outline-cut the hub to 4-7/8" diameter, flush with the parabolic nose. The arrangement allows for a smooth flow of air through the blades and greatly enhances the performance of the generator, in low wind speeds.

The Air-X blades, in a portable environment, are much more exposed to rough handling and damage, than they would experience in a permanent installation. A triangle shaped box will soon be built, to carry the blades, hub, shaft arbor and nose, together as one unit, in order to protect the sharp, thin blades from dings and damage, and ease installation onto the generator shaft, in the field.

Step 2: Simple Furling Device for the Wind Generator:

After a series of tests with the Air-X Airfoil blades, I then mounted the generator to a National brand spring hinge (Model# N190-736 V122), to serve as a furling device. With the weight of the generator too heavy to act as a vertical-furling device, the lightweight spring hinge worked quite well as a side-furling device.

The generator was mounted on a block of varnished wood, with the axis of the generator offset 1-5/8" from the axis (or pivot-point) of the hinge. The 1-5/8" offset provides the necessary leverage for the furling to properly engage when the wind speed reaches 9-10 mph (= 4.0 - 4.5 m/s). A wind speed of 9-10 mph creates a pressure of about 2 pounds on the spinning blades, initiating the furling process, and keeping the DC voltage output, from the generator, at a manageable level.

A 1-1/2" diameter hard nylon wheel was also mounted (with a large, long woodscrew, as the axle) to support the 5" swing of the furling generator. A rubber bumper was also added to the rear end of the generator to provide a soft-stop @ 90 degrees to the wind.

Some sort of furling device is required, when using Air-X blades, as they are quite capable of speeds of over 2,000 rpm, and, at that rate, require a generator with a much more thicker shaft, and also require a OEM diecast Air-X hub. My simple ABS hub (and tiny 5/16 inch diameter generator shaft) is only suitable for speeds up to about 750 rpm. Also, automatic furling eliminates the higher generator rpm's that cause premature wear on the relative small generator bearings, not to mention the possibility of burning out the electronic charge controller, which is usually rated with an upper voltage limit, as well as the strain on the lightweight portable mast and rigging.

Here are the results of the generator, with three Air-X blades, and furling device (but before the parabolic nose was added) under actual wind conditions (before the automatic furling kicks in):

3.0 mph (1.34 m/s) wind speed, generator spins @ 186 rpm, producing   5 VDC, 0.15 Amps, 0.80 Watts.
3.8 mph (1.70 m/s) wind speed, generator spins @ 269 rpm, producing   8 VDC, 0.31 Amps, 2.50 Watts.
4.4 mph (1.97 m/s) wind speed, generator spins @ 325 rpm, producing 10 VDC, 0.42 Amps, 4.20 Watts.
5.7 mph (2.55 m/s) wind speed, generator spins @ 533 rpm, producing 15 VDC, 0.83 Amps, 12.5 Watts.
6.0 mph (2.68 m/s) wind speed, generator spins @ 553 rpm, producing 16 VDC, 0.87 Amps, 13.9 Watts.
6.8 mph (3.04 m/s) wind speed, generator spins @ 573 rpm, producing 17 VDC, 0.90 Amps, 15.3 Watts.
9.0 mph (4.02 m/s) wind speed, generator spins @ 634 rpm, producing 20 VDC, 1.02 Amps, 20.4 Watts.

The wind generator maxes out at 24VDC, with the furling kicking in -no matter how fast the wind blows, although sudden gusts will sometimes generate short bursts of up to 34VDC, before the tail properly orients the wind generator and enables the automatic furling to take effect. The electronic charge controller is rated up to 25VDC (but takes the occasional 34VDC bursts in stride) and process it into a safe 14VDC - 16VDC for the sealed lead acid battery pack.

Step 3: Shortening the Length of the Blades for a Safer, More Portable Device:

Even in mild wind conditions, the Air-X blades spin quite fast -so fast the wicked "hiss" they generate actually makes my skin crawl. The thin, sharp, dense blades could easily kill anyone who gets in their way. You would NOT want to use these blades on a yard ornament. I painted the blade tips fluorescent orange and used fluorescent orange guy-lines to brace and support the mast. The generator blades are now well out of harm's way, with adequate, visible rigging in between.

In an effort to make the wind generator safer, more manageable -and portable, I carefully examined, and then sawed 4 inches off the ends of the blades (to a new over-all length of 18-3/16 inches long) and, after adding the parabolic nose, have yet to detect a change in the performance characteristics of the highly engineerd blades, except in the furling. The generator actually needs to be re-mounted on a thicker block of varnished wood, with the axis of the generator offset to a new position of about 2-5/8" from the axis/pivot of the hinge (but this has not been tested yet). A wind speed of 9-10 mph will now put a pressure of about 1.37 pounds on the spinning blades, initiating the furling process, and keeping the DC voltage at a manageable level.

Later... in an effort to make the wind generator even more safer, even more manageable -and even more portable, I sawed off another 5-1/16 inches off the ends of the blades (to a new over-all length of 12-1/2 inches long). And the generator still flywheels in 5 mph (2.24 m/s) winds, generates a charging current at 7 mph (3.13 m/s). But, now, the unit doesn't furl until 12 mph (5.36 m/s) winds, producing up to 40 Volts. As the spring in the spring hinge is not designed to be tampered with, to a weaker tension, the generator actually needs to be re-mounted on a thicker block of varnished wood, with the axis of the generator offset to a new position of about 3-3/4" from the axis/pivot of the hinge (but this has not been tested yet). A wind speed of 9-10 mph (4.02 - 4.47 m/s) will now put a pressure of about .67 pounds on the spinning blades, initiating the furling process. Also, with the shortened blades, a 24 Volt (instead of a 12 Volt) system may be desirable, and appropriate, for some applications.

But instead of fashioning new wooden generator mounting blocks, a quicker (if not elegant) way to initiate furling, to a lower wind speed, is simply to attach and stretch a simple rubber band, from the right-rear of the generator, to add .5 - 1.5 pounds of tension, coax the blades off their 90 degree (perpendicular) to the wind orientation, to advance the furling process, keeping the DC voltage to a manageable level. After all, once the blades tilt past 90 degrees, all it only takes about 1 pound of wind pressure to force (and hold) the blades into a 0 degree (edge-on) position, fully furled, which is the same regardless of the blade lengths. I enjoy designing and building aesthetic things, but there is no denying that the world is really held together with scotch tape and bailing wire.

But, ultimately, I decided that full battery charging voltage, in low wind speeds, was most important and ordered a new set of blades (over-all length of 22-3/16 inches). And a triangular-shaped case is being built to house the blades, hub, and shaft arbor -as one unit.

The spinning blades of a wind generator produce about as much pressure as a solid disk, of the same diameter. That explains why reducing the length of the blades will always require some sort of loosening of the spring tension (or leveraging) of the side-furling device: To change that simplified frontal "circle" into a more controllable ellipse, as viewed from the front, whenever the wind threshold is reached.

Some quick math indicates that the improvised generator, with full-length blades, without furling, could possibly generate 70VDC, 100 watts, @ 32mph (14.31 m/s) and spinning at 2,150rpm, which the Air-X blades, on a special Air-X hub, are fully capable of. But such voltage is beyond the ability to harness into any practical, portable capacity -not to mention designing a truly portable tower that could stand up to such a wind, with a generator that does not furl.

To complicate matters, many wind generators are marketed, posting their maximum watt rating -in almost gale-force winds, and novice owners mistakenly purchase high-current 12 Volt appliances, with the expectation their wind generator will always be able to power them. A good rule of thumb is 15% of advertised wattage equals the average wattage you'll probably get, in actual field conditions. Reputable dealers may advertise the maximum wattage in their headlines, to, understandably, catch your attention, but will also post a chart of actual watts, for given wind conditions.

Step 4: Mast and Rigging for the Portable Wind Generator:

Designed to fully take advantage of gusting wind conditions, the wind generator has an unusually large tail fin, as well as a ball bearing fitting on top of the mast. This enables the unorthodox device to quickly seek out and turn into the next wind gust, with the flywheeling blades always ready to harvest the often erratic and meager winds. The large tail fin also stabilizes the device during furling, holding the wooden body straight-and-true, into the wind.

A lightweight, but strong, 24" long stainless steel mast-pivot tube was cannibalized from an extendable shower curtin rod, from a local hardware store. The tube is a sturdy thin-wall construction, internally butted with plastic sleeves on the ends, providing a low-friction pivot that slips perfectly over the 1" diameter fiberglass mast.

The generator, Aix-X blades, wooden mount, tail fin, stainless steel mast-pivot tube, and power cord all weigh in at 9-1/2 pounds, total, and mounts lightly on top of an extendable 10 foot tall fiberglass mast pole (actually a modified tree pruning pole), in perfect balance. 4 guy-lines and hardware mount complete the rig.

I have recently replaced the original 10 foot tall mast, with a 15 foot tall extendable fiberglass mast (also a tree pruning pole), providing much better wind exposure, but the rigging needed to be refined to handle the increased stresses on the mast:

- Four additional guy lines were attached to the mid-section of the mast and tied to the four original ground stakes.

- A ball&socket plastic water shut-off valve was modified into an articulated ball&socket base for the mast.

The setup of the portable generator and mast is now greatly simplified by the ball&socket base:

- A plastic stake is fully driven into the ground, for the mast.  The stake is then carefully pulled out and the special, custom made ball-topped mast stake is pressed in its place.

- The looped end of a white nylon rope, with a red mark @ 13 feet, is slipped around the round shaft of the ball-topped mast stake, and the four anchor stakes are driven in, exactly 13 feet from the ball-topped mast stake.

- The non-looped end of the 13 foot white nylon rope is drawn taught and tied  to the ground stake that is downwind (leeward) of the mast.  This holds the ball-topped mast stake firmly in place for the set-up and take-down side stresses that will follow.

- The 15 foot mast is fully extended, with its internal wire connected to the wiring of the wind generator.  The wind generator is then slipped onto the top of the mast.

- The socket base of the mast is snugged onto the ball of the ball-topped mast stake.

- The upper rigging (4 guy lines) is attached to the mast, and 3 of the guy lines are attached to the ground stakes EXCEPT the 4th guy line that is upwind (windward) is NOT attached to its ground stake.

- Firmly grasping the 4th guy line, standing above the upper mast anchor, gracefully pull up the wind generator and mast, while walking back into the wind, and attach the 4th guy line to its ground stake.

- The entire rig will now be in its vertical, perpendicular, position and requiring only minor adjustments.

- Attach the lower 4 guy lines to both the lower mast fixture and ground stakes.  Carefully tension all 8 guy lines until the slender, flexible mast is straight and true.

- Take-down of the wind generator / mast is simply the reverse of the above.

The generator, from shaft arbor tip to tail, measures 45 inches. The power cord is routed through the ring-shaped ball bearing fitting, and inside the hollow, fiberglass mast. A standard RCA audio jack, used as an electrical connector, slips easily through the 5/8" diameter hole in the ball bearing fitting of the mast and down through the hollow mast. A slip ring (rotating electrical connection) is not needed, as a portable wind generator only pans a total of about 270 degrees, on a typical day.

The rigging attaches to a square piece 5" x 5" plywood, 11/16" thick, and glue mounted (PVC glue bonds well on both surfaces) to a PVC pipe which slips over the 1" diameter fiberglass mast. A thumbscrew tightened ring was fitted over the radial-cut end. 4 angled, thin plywood braces will later be added to the underside of the 5" x 5" plywood, for reinforcement.

The 4 guy-lines are firmly anchored into the ground with 17" long, heavy, steel "cork-screw" stakes.

The entire rig is easily set up and taken down by one person.

A side note:

I was recently invited by a local ham radio club to set up my portable wind generator, for their international ham radio day.  I was quite impressed with their portable 24 foot antenna masts, made from interlocking U.S. military surplus antenna mast poles.  These sturdy (2 lbs each), inexpensive, 4 foot long composite (resin impregnated glass fiber) mast sections can be purchased on ebay.  The mast sections have an outside diameter of  1-13/16", an 1/8" (.125") wall thickness, with a 3.5" long male/female coupling end.

Also, standard military surplus composite 4-point guy line attachment rings can be purchased, which slip on easily between any of the 4 foot section joints.  The guy ring is 5-11/16" diameter, drilled with four 3/8" guy line holes, with a 1.531" diameter center hole.

These pole sections not only allow for taller and stronger portable wind generator masts, it also makes the reality of truly portable 500 watt (500 watts rated = 75 watts typical) wind generators not only possible, but much simpler and affordable.       

Step 5: Physical Limits of the Portable Wind Generator:

I've test run this generator in winds up to 35mph (15.65 m/s), a "moderate gale", but don't recommend it. After all, the simple device is made of wood, and held together with glue and wood screws.

After about 5 hours of use in high winds, in an isolated area, I noticed a slight drop in voltage, and cautiously took down the dangerously spinning device, to inspect it, and noticed that the allen set screw, as well as washers and nut on the generator shaft arbor, had begun to work themselves loose! To correct the problem, I added aluminum shims to the generator shaft, neoprene washers, and a lock nut (detailed above). The spring hinge, fitted with special oversized wood screws, remained tight and required no adjustment.

This wind generator was designed for, and is best suited, for "light breezes" (5 mph = 2.24 m/s) to "strong breezes" (25 mph = 11.18 m/s), although a 21 Amp, 12 Volt battery was quickly charged in the 35mph windstorm test. And it was satisfying to observe the blades and generator desperately furling back-and-forth, while the entire unit, and the fiberglass mast, strained against the guy-lines, but held, in the insanely violent 35 mph (15.65 m/s) winds.

Also, violent, gusting winds will put a strain on the telescoping lock-nut of the 10 foot mast, causing the upper section to slowly work its way down an inch or two, giving the illusion that the guy-lines are becoming slack. The same applies to the lock-nut to the guy-line mount, on the mast.

Being portable, this wind generator will, more than likely, be used in close proximity to people, so safety is paramount. Keep the device under a watchful eye: If the winds really pick up, take it down. And never leave any portable wind generator unattended. Use the same care and precautions as one would use with a portable gas generator.

The 3-blade (and 2-blade) arrangement self-starts @ 11 mph (4.92 m/s) constant wind, and @ 13 mph (5.81 m/s) gusting wind, with the flywheel action of the thin, but dense, 3-blade arrangement sustains spinning of the blades down to 5 mph (2.24 m/s) wind speeds.

I have found that, on days of 5-10mph winds (2.24 - 4.47 m/s), "light breeze" to "gentle breeze", an extendable hiking staff, with a rubber foot, is quite useful to push-start the blades, intitate the battery charging process. Two or three of these "jump-starts" is all that is usually needed, over the period of a "light-to-gentle breeze" day, to keep those blades spinning and charge a 21-42 Amp battery pack.

Another way to "jump-start" the blades, if mounted on an unusually tall mast, is to simply run the battery pack power through the "generator" for a second or two, to get things moving. A 24 inch long string has been attached to the lower-rear of the tail fin, to serve as a simple telltale: 90 degrees = no wind; 45 degrees = sustainable blade speeds; 30 degrees to 0 degrees (parallel to the ground) = battery charging speeds.

As mentioned earlier, the generator is not yet weatherproof, even though all wood surfaces have already been given a good marine varnish. Future plans call for a simple, aerodynamic cowling, over the generator only, made from aluminum sheet metal and aluminum pop rivets.

Stay posted for more information and updates.


tyntop made it!(author)2016-05-02

Hi, great article, I am very interested in the automatic furling part of it, but I cant quite make out the layout of it, any chance of more pictures and details about this part as I would like to use it in a generator that i am in the process of making.

please could you contact me

email :



JerryY1 made it!(author)2016-02-26

I've been concidering building a wind generator, the thing I want to know is how do you stop it from spinning around and winding the lead out wires

shastalore made it!(author)2016-02-27

For a permanent installation, you'll need to install a slip ring (rotating electrical connection).

But for portable, temporary use, a slip ring is not needed, as the wind generator only pans a total of about 270 degrees, on a typical day.

nadrr made it!(author)2015-09-07


ddavis662 made it!(author)2015-08-03

Nice work!

I'm thinking about rebuilding my old wind generator. Was going to buy commercial, but I don't like what is available and think DIY are just as reliable.

bkalb made it!(author)2015-04-21

I highly recommend this site for PVC blade design. I am quite pleased with the performance of these blades.

anandpanackal2 made it!(author)2015-03-28


mikey51 made it!(author)2010-02-19

I don't understand how the furling device works.  When the wind picks up, what makes it pivot out of alignment with the wind?

Andsetinn made it!(author)2013-04-26

The motor is off-center, and mounted on a hinge on-centre, so strong winds will push the blades sideways, which reduces the surface are into the wind. If you google "windmill furling explained" there is a good explanation on the-back-shed web page.

Andsetinn made it!(author)2013-04-26

This is nice. A slightly more information on the build itself would be nice but the furling and bladesize info is worth a lot. I look forward to more instructables. :)

jdole1 made it!(author)2013-01-30

Thanks for posting this - I've looked everywhere for furling devices for homebrew / DIY wind, but the only thing I found was a $350 tail vane kit over at WindyNation!

If you feel like it, I bet you could sell furling tail vane kits (various sizes.)

sony+flores made it!(author)2012-04-16

please send me instructions and steps through my email:

Thanks a lot,looking forward for your favorable responds..

sony+flores made it!(author)2012-04-16

I just want to ask the electrical connection from generator to battery charger then to the battery to supplied appliances.

do i need battery charger or i can directly connect to the appliances.

i want to build portable windmill,can suggest me in order realize my plan without any expenses.?

i want 12V or any suitable for light bulbs only that can able to supply my house lightings.

jetboy made it!(author)2012-03-09

where did you purchase the motor at

Harry3Lime made it!(author)2011-09-13

How far from the pole are the anchors placed?

At what heights are the guy wires attached?

shastalore made it!(author)2012-01-17

The distance is already stated the instructable, but is always dependent on the height of the mast, so I'd rather not state an exact number here.

But a good rule of thumb is to place the upper guy wire hook-up as high on the mast as possible.

And for the distance for each of the four anchor stakes from the base of the mast, the guy ropes should be at a 45 degree angle, both from the ground, and the upper guy wire hookup.

But if you're setting up on sand -or on solid ground but with high winds, then 30 degree / 60 degree angles will provide better stability for your rig (30 degree angle from the ground / 60 degree from the upper guy rope hookup).

And for a mast taller than 10 feet, especially a slender, flexible mast, you will need to add a lower guy wire hookup, about one-third to halfway down the mast, and anchor those lower ropes to the same four anchor stakes. The exact positioning of the lower guy wire hookup is best fine-tuned during high winds, carefully observing what position provides the best bracing and rigidity of the mast.

And don't hesitate to add yet a third guy wire hookup, if you're really ambitious and building yet a taller mast than my 15 foot version.

ddavis662 made it!(author)2011-09-10

Cool idea!

stephenniall made it!(author)2009-05-07

Looks great aestethic wise and it is a Great product im thinking of making a miniture version !

shastalore made it!(author)2009-05-07

Go ahead and build it. Looking back, I designed on the side of caution, and made it a little too heavy and sturdy. You could actually build this wind generator much lighter -and use the same generator. I may also do just that, and mount a new generator, with 50% more power, on my existing wooden rig. As for the over-all design, I tried to give the wind generator a pleasing profile, with classic lines. A habit I developed early in life, with balsa model airplanes, with a zero-tolerance for weight.

Sundialing made it!(author)2010-08-15

So How do I buy One *** ??? Miles Of Smiles Sundialing

DieCastoms made it!(author)2009-05-14

Would it be practical at all to construct most of the fins and possibly some of the blades of this style generator out of Lexan or some other acrylic sheet? Nascar uses Lexan for their windshields so it should hold up in this use well enough. UV may be an issue, but there is also UV protected Lexan. Using the Lexan would fairly-well make the blades and fins disappear or at least blend into the background better and possibly be less obtrusive. Just my $.02 DC

grunthos made it!(author)2009-05-20

Lexan/polycarbonate, yes. Acrylic, no. While acrylic looks like polycarbonate (Lexan), they are very different. Acrylic will break and shatter very easily; it doesn't have the strength. Polycarbonate does. I would be wary of invisible blades being dangerous.

shastalore made it!(author)2009-05-15

Sure, it could be designed, with Lexan, to function well. Just don't design the blades to be invisible, for safety reasons -at least for a portable wind generator. I've noticed that hobbyists and tinkerers tend to plan and build their projects with the most expedient means and materials at their disposal. For example, I was quite intrigued by a post about a wind generator that a hobbyist had put together: It was fairly easy for him to sand-cast an aluminum mount for his generator and quickly machine it down, to snugly fit and bolt into place! What someone on REALLY needs to do is re-design my generator, with graphite composite frame for the vane/fin, with a nylon fabric tightly stretched over it. The weight of the generator and blades are pretty much set. But the over-all weight of the portable, furling generator could then be cut 30%.

Abovethesky made it!(author)2010-07-14

I have 12volt stepper motor it generates 103volt ac how I recharge my 12volt batteries.

ChibiButo made it!(author)2010-05-23

 awesome try going smaller for like a altoides pack 

timbaker172 made it!(author)2010-01-24

Wow! Thanks for showing those detailed pics of the furling system. I have been trying to find a simple way to make a furling system for a week now. For some reason a spring loaded hinge did not occur to me. I have already built a small turbine that charges NiCd AAs and I'm working on a bigger one. My next step is to try this hinge idea on the little turbine first.  Thanks again.

batonas made it!(author)2009-10-15

you would get more power if you use a gear box or a sheaves

shastalore made it!(author)2009-10-23

I initially considered a gear-up, with my first set of orthodox, but crudely made PVC blades.

But I wasn't wild about the idea of the energy loss in the transfer, not to mention the additional weight, complexity, and maintenance issues that are inherent with going in that direction.

You may have noticed that my devices appear, at first glance, quite simple and obvious.  But I prefer to put a lot of sweat, research, and field testing into these things, and generally feel that the end product is worth the time and effort.  But none of my projects are never really finished, as I sometimes tend to re-visit them a year or two later and the compulsive tampering process begins anew.    

ANDY%21 made it!(author)2009-05-07

SWEET. Is there any way of building the blades for real cheap cause I don't want to buy one. 5 out of 5!

snotty made it!(author)2009-10-17

Yes! I just figured out how to make bamboo wind turbine blades. They are very easy to make, they perform well and unlike PVC they won't kill you with liver cancer; so I think they are pretty nice.

shastalore made it!(author)2009-05-17

There may be a way to quickly and cheaply scratch build a set of high performance blades, matched to the generator, but this subject, in itself, would be an involved and time consuming research project, but an excellent post for, for someone to attempt. But I simply determined that I just don't have the time to go in that direction. I simply bought a set of 3 Air-X matched blades, for $ 100.00. They appealed to me because they were off-the-shelf, and, luckily, had the tried-and-proven performance characteristics I really needed. Another advantage is that I could quickly buy some more of the same blades, if one of mine became damaged. And after I received them, I seriously doubt that I could easily build a set of blades, this well designed. Really, some of these manufactured blades are amazing. The Air-X blades, for example, have a slight swept-forward cant, from hub-to-tip (my sketchy plans called for more). And they're extremely stiff and rigid, with an airfoil cross-section (my rough plans had a thicker cross-section). And they would have easily out-performed my scratch built blades. To build these from a PVC pipe, or wood, or fiberglass, could be false economy, as the blades are just as important as the generator. And many of the homemade blade designs on the internet are poorly thought out, and there's rarely any information provided as to how much power is generated for given wind speeds, or how many rpm's are generated by those winds. "5 out of 5"? Thanks! (somebody tell my wife that)

ANDY%21 made it!(author)2009-05-18

How should I cut PVC?

shastalore made it!(author)2009-05-30

There are numerous plans and cutting methods on the internet as to how to do this, but they tend to be be sketchy and incomplete. But if I were to build a blade from PVC pipes, I would only do a 2-blade design. 3-blade and 4-blade designs tend to falter when they attach to a simple flat disk hub, where the curve of the blades is distorted by the mounting bolts, creating unacceptable drag and a critical loss of performance and rigidity. A 2-blade design, made from one length of PVC pipe, eliminates the need for a separate disk hub and runs much cleaner, from an aerodynamic standpoint, as the blades angles are, simply, correct. First, draw a straight line down the length of a 4 foot length of PVC pipe, 6" inside diameter, 3/32" wall thickness. At the middle of the PVC pipe, carefully mark the point, which you will later drill out for the generator shaft arbor. This line will be the the trailing edge, of both ends of the finished blades. At each end of the PVC pipe, mark a 1 inch width. This will be the width of the tips of the finished blades, as well as the leading edge of the finished blades. 2 inches from the center point (arbor shaft) of your original straight line, and at a right angle to your original straight line, draw a 5.3125 inch arc along the outside of the PVC pipe. This will be the leading edge width of your finished blade. Repeat the process for the other side of the center point, but reversed. Using a flexible ruler as a "straight" edge, draw a straight line from the 5.3125" leading edge point to the 1" leading edge piont at the end of the PVC pipe. Repeat the process for the other end of the pipe, but reversed. This will be the leading edge of the finished blade. Using the same flexible ruler, connect the unmarked areas at the hub with a diagonal line, spanning the 4" area covering both sides of the center point, running from the 5.3125" width mark to 2" mark on your original straight line. Repeat the process for the other side of the center point, but reversed. This layout should produce a blade that will spin faster than most PVC blade designs, will provide more low-end torque, and will produce less high rpm drag. To cut out PVC blades, I use a Dremel, fitted with a small cutting wheel, and simply and quickly do a freehand outline cut. The edges are then quickly, and accurately, dressed out with a rough file or rasp. The back (leeward) side of the blades then need to be beveled, to improve the aerodynamics. But leave the outline of the concave (front) side of the blades absolutely sharp, holding to your orignally drawn dimension lines. To mount the 2-blade piece on the shaft arbor, you'll need to reinforce both sides of the blade "hub" with a front piece, and back piece, from the same PVC pipe, cut with an outline to match the hub of the blade. Glue and clamp. When dry, carefully file down both sides (concave front & convex back) of the "hub" until they're absolutely flat. If you have a drill press, this is easier, in that it can be, slowly and carefully, done with a wood boring bit, the same diameter as the shaft arbor washers, as a light "touch-bore". Next, drill out the hole for the shaft arbor. The glued "hub" must cure for at least 24 hours before testing the blade in the wind. Be advised that PVC blades should only be used on a generator (not the one I used) that turns at no more than about 350 rpm. Also, strong winds can bend the blades back enough to actually strike the mast. Also, cold weather can make the blades brittle and crack.

Dr.Bill made it!(author)2009-05-18

some of the other wind generator instructables have plans for PVC blades

balexander87 made it!(author)2009-09-29

Do you have any suggestions for places or devices from where a suitable charge controller may be salvaged? Love the project. Very well done.

shastalore made it!(author)2009-09-30

You'll probably be better off just buying one of the new electronic charge controllers on the market, as they're becoming more economical, and portable, every year. But check out ebay and see what you come up with. You'll need, in all cases, an electronic charge controller. A simple diode will not prevent the wind generator from overcharging and burning out your lead acid battery. I purchased a "Chanyn" Model#CQ1210, for $ 55.00, on ebay. It has separate contacts for: Battery, Wind Generator (or Solar Panel), and Load (aka 12 Volt appliances). The charge controller will also prevent the battery from discharging too low, greatly extending the life of the battery.

balexander87 made it!(author)2009-10-01

Thank you for the pointers.

electronic+boy made it!(author)2009-09-04

where can i get the generator? please give a web adress

shastalore made it!(author)2009-09-04

The exact motor I used for the generator is: 370-350-00 PE24113G 48VDC They sell for about $ 300.00, through the medical parts suppliers, but I bought mine from USA WindGen turbines, Athens, Texas, as a surplus item, for about $ 50.00. He also sells on ebay, as "otter5555", and he just may still have some of these on hand. I think he received some flack selling these motors, since some of his customers complained that they rusted out. But the quality of this motor/generator is excellent. Since it's portable, just treat it as a fair weather friend. Stay posted, as I will soon build an aerodynamic, weatherproof sheet aluminum jacket, to fit over the generator, with aluminum pop rivets.

luvit made it!(author)2009-05-08

ah.. the moderm convenience of being rustic with nature. i'd add whistles to the blades so people would notice it.

Dr.Bill made it!(author)2009-05-18

Maybe 3 different sounding whistles would really whip things up !

Dr.Bill made it!(author)2009-05-18

And keep the monsters away !

shastalore made it!(author)2009-07-31

For the benefit of our readers: I'm personal friends with "drbill" and we enjoy razzing each other.

shastalore made it!(author)2009-05-25

The Air-X blades make a god-awful "hiss" that is clearly heard by anyone in close proximity to the generator. The blades are even made of black plastic, to appear serious, and dangerous. The spinning blades naturally appear and feel threatening to anyone who observes them up close. But from a distance, the wind generator is silent and is completely obscured by normal background sounds. Mounting a whistle on the blade tips would certainly affect the high-speed performance of the blades, as well as creating unacceptable noise in the vicinity.

luvit made it!(author)2009-05-26

you make me like it more. so i need whistles.

yachtmaker made it!(author)2009-07-20

can the generator be used with a straight to inverter to provide AC for perhaps a small radio?

shastalore made it!(author)2009-07-29

If you want to use a DC-to-AC inverter, you would have to hook it up to your 12VDC battery pack, and not directly to the wind generator 12VDC output. But precious electrical power will be lost in the conversion process, even though DC-to-AC inverters are more efficient (and "smart") these days. For good example: A typical UPS system (computer backup power system) is a heavy, bulky unit that will only power a 120VAC desktop computer for a few minutes, just enough time to logoff and shut down. And I rated my portable wind generator at "17 Watts" to give, those who build one, a good range to carefully select the 12VDC appliances they'll need it to power. And I mean carefully select your appliances. For example, a 12VDC-to-19VDC converter may be needed to power a laptop. But a basic research into such a purchase will reveal that 12VDC-to-19VDC converters have wildly different 12VDC current draws. That is, two 12VDC-to-19VDC converters, of the same brand name, will power a laptop, but one model may cost twice as much as the other, but consumes only half as much 12VDC power from the wind generator's 12VDC battery pack. Electrical appliances should be appropriate for the wind generator/battery pack. In other words, 12VDC appliances should be used with a 12VDC generator/battery pack. And to do otherwise would be false economy. And 120VAC appliance manufacturers seldom have portability in mind when they build them. There are plenty of small, portable, and efficient 12VDC appliances on the market that were designed to squeeze the maximum output, with the least current possible.

tezzz made it!(author)2009-06-21

Iv'e often thought of building a vertical blade system using venetian blind blades. I don't know if they are rigid enough but can be built to any practical length and don't need to worry about wind direction. It could be clipped to a campervan as a backup. I have these ideas but never do anything. anyway what do you reckon?

shastalore made it!(author)2009-07-20

I reckon you give it a try. It's always fun to see what people on Instructables invent. But venetian blind blades seem too flimsy for power generation for a typical RV, although they could possibly be used on tiny, low power science fair projects.

mduhe1 made it!(author)2009-07-18

what is an automatic furling device?

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Bio: Industrial Arts, Appalachian State University. Recession has dried up my field (commercial printing & packaging), but have found new work in staging, lighting, sound systems, sets ... More »
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