Partial Demo
Plans for the Dragonfly Wind Generator

Table of Contents

wind generator


If pictures don't show in these plans, it's because this web page file (Dragonfly Plans.htm) has been separated from the folder which contains the "images" folder. These must be kept in their original folder arrangement, so that the written html source code refers to their right location.

These plans can be printed from your computer. The page numbers are probably off because I've been updating sporadically since 1980. Most drawings have buttons to convert inches to centimeters. They also have drag-&-drop printable templates that can be pasted to the material for locating drill centers.

Sometimes my source links go out of date because suppliers change their catalogs and don't tell me. If you reach a dead link, please google it, that's what I do. And tell me about the link.

I'm unfamiliar with standard metric sizes for lumber, pipe, and fasteners. Please round the decimals up or down to fit the occasion.

Part numbers listed in a description, such as E-13 or T-5, are referenced in the Parts list. Which, with the small version of the Layout Drawings, can be opened and printed separately. You'll need this list in hand when you read the drawings. The part numbering code is: E = Electrical, F = Frame, C = Feathering Carriage, T = Turntable, and B = Blade. (D means Drawing).

I've been told that these plans rate from excellent to incomplete, but describing every detail of every step is just not possible. Somewhere, I have to assume understanding has happened. Anyone who wants to make their own juice, needs to have their own inner resources. Descriptions are generally self evident with the actual part at hand. But if you find something is obscure (or faulty links), please let me know.

Bill Cornelius

Turntable Assembly Procedure

1. Solder the wires (E-l & E-2) to the inside of the two sections of copper tube (T-8 & T-9), which are the commutator rings. The wires may connect to either tube, but remember which is which, so the mast wires don't get connected to the wrong terminal. To solder them without melting the wire insulation, strip about 3/4" (1.9 cm) of insulation off the end of the wire and form the wire to the right shape so it'll fit flush against the inside of the tube. The insulation should extend inside the tube a way but not touch it. "Tin" (melt some solder on) the ends of the wire and also a spot on the inside of the tube. Then just lay the bare tinned wire inside the tube and apply enough heat to the outside of the tube to melt the solder and it's done. Be sure the wire insulation extends inside the tube so the circuits don't short against each other. I use a propane torch, but it can be done on a stove.

Slip rings
2. Prepare the copper tube commutator rings to fit with the plastic pipe couplers used for insulators (T-10) by beveling the edges with a file. Clean the outside of the commutators and the inside of the insulators with sandpaper and see that they fit smoothly. The short commutator tube goes on the bottom end and the wires all come out the top end. See right, also Exploded View D-1, in the lower left. Prepare the end of the one inch pipe (T-3) with a rat-tail file. Remove any burr and smooth down the seam that sometimes sticks up as a ridge on the inside of the pipe. The actual dimensions of these pipes vary from l" to 1-1/8" (2.54 - 2.86 cm) usually closer to 1-1/16" (2.7 cm) . If you should have to buy another insulator to replace this one, they come in various outside dimensions depending on the mood of the manufacturer, so measure them before you buy and, if you don't find it at first, look around. They cost about 25 cents. You'll only need half of a coupling for this insulator (cut across the diameter), and as the coupling is tapered slightly toward the ends, start the small end. Coat the inside of the pipe and the outside of the insulator with a formica adhesive (any brand) and drive it in with a few blows of a sledge hammer and a block of wood to prevent breaking the edges. The preparation with the file will let them fit easily. Let the glue dry for a few hours. Meanwhile assemble the other two copper commutator tubes the same way. Take care though that they don't touch each other in the middle of the insulator (that's what insulators are for), Measure and mark them and put a piece of cardboard or garden hose washer in between them if necessary. The insulators that come with the kits have a ridge inside in the middle, but be careful anyway. While all this glue is drying, you can read a book or hoe your garden or do dishes or something, but don't drink no beer because you'll end up with a lawn ornament instead of a wind generator.

3. After the glue is set, glue these two subassemblies together, using the same technique. To get the right gap for the commutator brush to fit between the ends of the insulators, clip one over the copper tube before you press the tube into the insulator. Stop driving when you have just a little more than 1/16" (0.16 cm) space on either side of the brush. Now, while the glue is wet, quickly eyeball the commutator tubes so that they're centered on the same axis as the pipe, if they're a little bit off it won't hurt. In fact, if they're quite a bit off it won't hurt, so long as the insulators don't rub against the frame. Its easy to bend them straight before the glue sets.

4. The commutator brushes (E-6) transfer electricity from the windmill to the battery without twisting the wires on the tower when the wind changes direction, they are made from .015 gauge (0.318 mm) automotive brass shim. They contact parts (T8) & (T9). Here's a drawing to get them the right shape:

This washer
is inside the
insulator block
under the brush
Solder E6 E4 E7 E6

Jacobs brushes were made of sandwiched layers of graphite and carbon to scour the contacts and never need cleaning, but they cost the equivalent of $60 each. This kind should last about 3 to 5 years and cost about $0.15 to replace (not including labor). If you want them to last longer, make the pad with more folds, but don't get it too thick or they'll ground against the frame. Clean off any excess globs of solder, better yet, use silver solder. Be sure the folds in the contact pad are crimped tight and flush. The astute windmill fanatic will make up a few extras and keep them in a baby food jar along with any other odds and ends, like small nuts and lock washers, 3-amp fuses, crimp-wire terminals and some wire, etc. Secure the jar lid to the underside of the Dragonfly frame so these things will be handy where you need them so you won't have to climb down and run into the shop to locate some kind of infuriatingly minute particle of diddly (& don't drop the jar). Gasoline and a toothbrush will clean off corrosion buildup on the commutator tubes (with the power disconnected, right?), otherwise, with time, too much corrosion will prevent brush contact and won't pass a current.

part T5
      5. This tube guides the feathering cable through the wooden frame and anchors a vinyl tube inside the turntable. The vinyl tube should be pushed over the inside end of this 2-1/2 inch piece of 3/8" copper tube (T-5) that seals the hole under the pulley (with a dab of calk). Install it just before bolting the pipe flange to the frame because the copper may accidentally get bent if it sticks out while you're working on other parts. The plastic vinyl tube (T-6) should be inserted from below. It's there to contain any water coming in through the hole for the manual feathering cable. It also prevents the bare feathering cable from shorting any circuits of the commutator assembly. (See drawing for the fancy details). The end is split with tin snips, formed in a copper tube flaring tool, and hammered flat on top. If you don't have a flaring tool, it's not critical, just make several cuts with tin snips and fold the tabs out like a star, but see that two of them go under the cheeks of the awning pulley where it touches to hold the tube solid. The hole should be open enough to allow the feathering cable to pass through without chafing the copper.

6. If you have to replace the feathering pulley (F-8), use one without an aluminum roller, the feathering cable saws them in half.

7. Here's a drawing of the outer turntable sleeve (T-4): * Thread this hole for ground lug screw.

*Thread to

T4, Turntable sleeve

Part T4
This rectangular hole may be cut by drilling a series of 3/16 (0.47 cm) holes on 1/4 inch (0.63 cm) centers. Knock out the connecting metal with a cold chisel and file off the sharp edges. The cross cut is easiest with a hack saw. Remove the dotted area for systems with two field wires. Neg. Lug on Turntable sleeve
The round hole on the right end is to attach the ground (negative) wire with a threaded lug. Like this: --->
A threaded hole for a machine screw is simpler but a lug sticking out is easier to deal with in a cold wind. If you don't own a tap & die set, another way is to slip the bare end of the wire under the straps that clamp the pipe to the masthead.

End Turntable Assembly Procedure

end partial demo. Copyright Bill Cornelius 1981