ZubWoofers

[Peppyy]

I have the basic ingrediants but I have a couple questions.

I have my ametek 40v 6" motor and basic frame.

6' of 4" recycled pvc pipe.

#1. What length blades would be the right size for the motor?

#2. How many blades do you get from 1 piece of pipe?

#3. To mount the blades to a round, plain shaft what would you use"

My current 21" round prop is mounted using a 3" X 1/2" threaded pipe nipple which fit over the shaft with just a bit of milling on the inside. In fact during the fitting, I tapped it with a block of wood and was unable to remove it again so I gave it a couple more love taps. With my wind situation I can't get enough continous wind to stay above 12v so I think these might be just the ticket.

There is quite a bit of room for flex in the blades amd my motor mount is adjustable if I need more. Have 8" or 9" now and will have about 12" an a real tower.

Any and all ideas accepted.

Thanks, Pep.

[Jerry]

This was easy and work fair.



JK TAS Jerry

[nothing to lose]

General observations from what I have just made, not a permanent set up though, just some testing on a different motor.

4" green PVC sewer pipe seemed quite strong. So far I have no worries about flexing or breaking in normal fulltime use (while new). I do know from other uses in the past that direct sun will dry out the oils in the plastic and it will eventually get faded, brittle and easy to break, or if bad enough even simply crumble when squeazed in your hand. How long I left it lay not sure? 1yr or more maybe laying beside and old trailer house in the woods. It is not UV stable itself and will need some type of protection (maybe paint it?) for long term use, or use better stuff that is uv protected, or check and replace them as needed (cheap enough). If I do use these permanantly on some motors I will just coat them somehow and make a few extra sets for spares and keep them stored till needed (if ever).

Very easy to cut, I used a jigsaw. Might have been a fine tooth metal cutting blade I had been using for cutting custom computer cases. I didn't look at my blade, it worked so I used it.

I got 2 full 2 blade (with hub) props, or 1 4 blade prop depending how you look at it.

Also 1 2 blade prop with only half the hub.

Also enough material left over for maybe 2 blades without hubs, maybe more.

If laid out better you might get more or a better hub on the third 2 blade set.

If not wanting the hub and laying out the pattern better than I did I would say you could get maybe 8 individual blades from one round peice. As blades only and flipping the hub end (widest part) from center to end of the pipe, blade to blade  you may even get more single blades.

For test mounting (only) I already had a 3/4" 4" round plywood hub on my motor with other blades screwed to it. The hub had a smaller hole than the shaft and was driven on with a hammer, VERY tight fit. I took those blades off the hub and installed 1 2 blade set onto it. For this I just centerd the hole on the shaft and used a few wood screws on the center line. For testing this worked fine, I think it would work ok permanent also if done BETTER. Like secure the plywood hub somehow so that it could never just wiggle loose and fly off the shaft. That would be my worry. Also screwed on better than I did for just testing.

 I feel the plywood hub behind the blades also helps strengthen the most stressed points. If making a 4 blade some cutting will be needed in the hub area I think on one set so I like this extra strength myself rather actually needed or not.

 To secure the wood hub to the shaft then I am thinking a simple pipe nipple slipped over the shaft, drill a hole in the side of it, tap it, and use a set screw. One front and back of the hub. Simple, easy, strong and secure. Could also weld on a small nut if wanted instead of tapping the hole, or do both. My thought, maybe other easier or better ways??

 As for strength, they seem strong enough, I saw the 2 blader almost at a blurr (no load) a couple times, did not SEE any noticeable flexing YET myself to worry about. Nearby tall thin trees were swaying and bending pretty good, NO LOAD on gennie though.

When cutting your blades be aware (as I forgot and messed up), I marked the center line on top, rotated the pipe so it was on bottom to mark angles, then back over to top to layout the cut lines. I made a COUNTER CLOCKWISE 2 blade set this way.

Next blade set I took a short cut, I already had my template for the center hub and the size of the tips, so I simply laid it out all on top. I cut a CLOCKWISE 2 blade set

 I have almost exactly the same thing for both sets of 2 blades, but opposite rotations. They would fight each other as a 4 blade set!

DUHHH, on me!!

 It's actually ok though since I will want a 4 blade set of each, I just have to do 2 more the same way I did these

I am where the only two things I basically have to worry about myself is either being hit by a blade or busting a window in one of my many unused vehicles in the yard, NOT where I have to worry about hurting others. I was testing an unloaded genie kinda wanting it to go nuts looking for weak spots, like if any Mags break loose and such before going for a permanant mounting and building more if this one works well.

One of the things I am thinking for blade mounting that might work well. If I can get a 4 way fitting for this size pipe. I could slice that down the center for 2 halfs. Mount a half fitting to a wood hub, sit in a 2 blade set and mark where the blades sit in each of the 4 ends, then glue single blades in those marks and use screws as well. I have not tried this or checked the price of such a connecter yet. Just thinking it might work well for a fast strong hub for a 4 blade set and alough more single blades to be cut without hubs from a single piece of pipe. Also a little shorter pipe piece since you would not have the hub in the center, or alot shorter if all the blades are cut from one end, like 4 blades without hubs from a 22" long pipe for about 44" rotor or longer after hub mounting.

I would point out I am not concerned about direction of rotation with this since I want both. A project when finished will have 4 motors/gennies and I want 2 each direction. So rotation does not matter to me as I cut blades for this project.

[Peppyy]

Thanks so much. The cross tee sounds like a great idea. It might be possible to get a 4" for the back and a 3" to use inside to make a sort of sandwich. The other possibility would be to make 4 seperate blades and keep the entire round on the end so that it fit naturally inside the fitting.

Excuse the quick drawing. I know I would need more pipe but it might be worth it in the long run. The center of the cross tee could have a bushing inside to keep it from compressing when the mounting nuts were tightened. Might even be able to cut some curved caps or inserts to close off the open circular space inside the hub. That should make them strong enough. The tough part would be gluing them in just the right place to get the same optimal pitch.

So somewhere around 4' in diameter should be about the right amount of power for a genny of that size? Say, 4 - 22" blades and the hub. I have studied the drawings and photos and noticed that they look to be quite narrow. I would guess that you wouldn't want to use more than 1/4 of the pipes cercumference at the base of each one, otherwise it would lose power due to the drag.

Worth a try?

[Norm]

   I kinda favor Jerry's hubs for attaching the blades...if you're afraid of detachment extend the sides of the hub and have deeper slots for the blades.....

   I use a regular handsaw for cutting the plastic pipe sawing at an acute angle to the work (for the straight cuts) jigsaw only for the curves, smoothing the edges by scraping with a utility knife (I'm always amazed at how easy it is to smooth and round the edges this way)

      Cutting plastic pipe is just a whole buncha Fun! I don't care if some don't think it's as efficient as wood props...it's just fun to watch them spinnin'

                  ( :>) Norm.          

[nothing to lose]

"The center of the cross tee could have a bushing inside to keep it from compressing when the mounting nuts were tightened. Might even be able to cut some curved caps or inserts to close off the open circular space inside the hub. That should make them strong enough. The tough part would be gluing them in just the right place to get the same optimal pitch."

Couple things about cutting them in half I liked, but not everyone likes the same things though.

A four way tee cut in half would make 2 hubs and of course cost less each. Being both sides of each mount area is there and also conntected to the next side in the middle of the fitting you should have more strength all ready than  the blade itself will have at the root (mount). Using half a 4Way I think you can lay in a 2 blade and hub set and mark the correct mounting points/angles easy. May have to trim the hub to get it to fit inside the center.  No need for bushing to prevent crushing or caps.

 I do plan to make sort of a nose cone later for all my mills, mostly just for looks, so that would deflect wind to the blades at the hub and also block off the hub from the wind.

One of the reasons I came up with the thought is because it makes blade changes so easy  also durring testing or if one needs replaced for some reason later. I can make half a 4 way and 4 blades, fully assemble in the house and just use a cordless screwdriver to run out about 8 or so screws from the existing set on the mill and run them back into the new set. That fast and easy if you can get to the mill easy. Course if I am using a nose cone I have to remove that. But mounting the new blade set would be as simple as lining up a hole in the center with the motor shaft and driving a few screws into the already mounted wooden hub.

If I ever needed to replace a plastic blade I would replace all 4 anyway. I mean I am sure I would never get one blade as an exact match for the other 3 all ready in use. Balanced and all that?? I'd just swap the whole set out.

I do like Jerry's wooden hub also. I will make one of those also probably, maybe more.

I am sure it would work as well with 4 blades on 4 sides as 3, and I want to try 3 bladed also anyway which would be pretty hard to do with the half fitting idea. Maybe I could get an equally spaced Y fitting, but I have no idea if they are are spaced even or just some odd angles off hand. Pretty sure for 3 blade Jerry's would be easier anyway.

[Peppyy]

Plumbing angles are 22-1/2, 45, and 90 degrees

so I don't think you can find a 120 degree Y

but that would be really neat! I guess my first

step is to make the blades. I think I will

build the 2 blade ccw like you have made and

go from there. At this point the pipe is free

and the only cost will be the time.

(Any time I get to play in my office/shop

is quality time). I want to chart my

voltage / windspeed with the current prop

today so I have a reference to start.

I was going to add  some load but I don't

think I am going to have enough wind for that.

I have a real nice leaf-blower though

I like Jerry's hub design for the blades he used.

They look kind of like ceiling fan blades

except for the curve. I am going to save my wood

carving skills for the big machine.

[Jerry]

Here is a picture of the baking plate of a speaker magnet. Most of these allready have a center hole of about 1/2". Of course the hole is much larger on larger speakers.

I drilled a hole through the smaller diameter part and tapped it for a set screw.

This make a good metal hub to secure your wood hub to. Now just drill a few holes through the flate portion and use wood screws to secure the larger wood blade hub. Works lika dream.

By the way some large speakers have up to 8" dia. backing plates. I've started a couple disc alts with these big ones.

Check at your local car stereo shop they through piles of these things away every week. Its a great source for doughnut ceamic magnets also.



JK TAS Jerry

[Jerry]

Here is the round wood 4 blade hub although square would work also.



Here is a smaller hub made from a smaller speaker magnet backing plate.



JK TAS Jerry

[Jerry]

PS. The center hole can be drilled out to larger sizes. Its best to do this on a drill press or a lathe to keep good alignment.

                            JK TAS Jerry

[nothing to lose]

Thanks again Jerry your great!

I never knew there was anything heavy and useable in those old speakers other than the magnets. Only ones I ever really ripped apart were smaller ones with very fine wire that kept breaking as it came out. Also think I had trouble getting the magnets off back then too. That was probably close to 20+ yrs ago though so I kinda forget. Plus alot may have changed.

What's your methode to remove the mags without breaking them and are the larger speakers using heavier wire? What's a good size to start with. Most likely I was trying to use smaller speakers in the past, not 8" and larger ones, maybe that was why I thought of them as useless back then also. Probably AM transistor radio types.

I may start cutting a few cars into pieces soon (30+ and getting more still), several will be scraped for parts for others and variuos projects. Also where I will be getting spring steel and aluminum from for my Blacksmithing and casting.

Are the stock speakers in these 80-95 Ford/Mercury cars and Pylmouth/Dodge mini vans worth messing with? I haven't taken one out yet so I haven't even seen whats in the dash, doors, or rear pannels now a days.

Maybe that would be an interesting post you'd like to do sometime if you haven't already. Show ripping a speaker apart to get all the usable parts and how they are made. Maybe general sizes of wires used, how to remove the mags without breaking, best sizes or what is to small to be much good. And also important is rather it's worth destroying a working speaker to get the parts or not. Most of what I have work, but I have far too many, but I never killed them just for the mags yet. Just got em stacked up taking space I need, as far as the ones not in cars.

I do have some very large 3-4' box speakers I used for end tables once, don't know what the actaul speaker sizes inside are though. I think they were used by a band and one speaker is blown. Think it worked but was nasty sounding.

[ghurd]

I think they call it a "Double T".  

A 4" is like $18(?) here. The problem is they have a 'drop' or the 2 sides curve down to the middle to aid flow to the drain.  This will prevent a straight pair of ZubWoofers.

Something for a 'vent pipe' may be straight accross on all 4 pipes, but I have not found it yet.

Also...

Cut the blades oversize. A lot (1/2" extra all around).  Let them sit where it is warm for a few days to get the stress out.  Then mark and cut the final lines.  Otherwise, they will warp and twist as you cut them.  No two blades will look the same.

FYI-  There were companies making UV resistant colored PVC for DIY PVC furniture plans 10 years ago.  I will just spray paint mine.

G-

[nothing to lose]

Thanks,

I'll probably just paint mine too. I knew about PVC furniture plans, didn't know about the colored pipe or being UV protected. I know they have Grey electrical, think I used 3" for the house lines but too expensive for me for other stuff.

$18 for  double tee I'll pass on that then, was an idea anyway. And I also thought it was straight through basically, just a little smaller where the inserted pipe is supposed to stop. Guess I was wrong and glad I did not waste my time or money on that then. I was going to make a trip to look for one today, but they closed at noon today and I did not have time before that. About 25-30 mile round trip.

I'll cut em large and let em sit next time as you mention then. I thought some of it was my bad cutting.

I changed the blades on my test gennie again today. I had taken off the small barrel blades I had made then used the single 2 blade set. Today I took it down and installed 2 more single blades. Also changed the tail, I found a problem the way it was.

With a longer 2 blade and hub set, and the 2 shorter single blades it spun up pretty good. When I put it back up I had the wires shorted, it was kinda stiff to turn and it caught the wind and was running a constant slow speed even shorted. Open no load it went pretty fast.

I get some pics I'll update the post "What not to build" and show it now.

I did get a minor ouchie today doing something else, nothing bad, just hurt my hand abit, but it stopped me from getting as much done as I wanted today and will probably keep me slowed down a little for a few days. Otherwise I would have the mill mounted on the truck and in good wind up higher and be checking power output now.

[ghurd]

The $18 "T" could be for 6".  Seems dang steep for 4".  Thought it was dang steep at the time, either way.

Two long and two short? Will one drag down the other?

I have stuff everywhere waiting for the rotors to come back from the machinist.

He is still drinking coffee, telling me "Pretty Soon".

I don't have an good axle to hang stuff on yet, genny or blades. Don't even know if I need to re-wind this micro stuff.

G-

[baggo]

Hi ntl,

Have a look at my website here:

http://www.baggo.copperstream.co.uk/Small%20A%20F%20Genny.htm

This shows in detail how I made a 5 inch dual rotor alternator from old speaker pole pieces. It will produce about 50 watts. It was not intended to be a serious power maker, more a fun project to gain some experience. I have some larger assemblies that I will use when I get time.

Hope that helps.

John

[Peppyy]

Nice article. I was really surprised at the increase in power you got by doubling the magnets. Did you ever try another coil set for it or did you just go back to the original? Sometimes the first ones are the best after all.

If I ever get the chance I am going to try and finish my PVC blades. I have modified the design just slightly with a slight curve on the leading edge so it tapers a bit more quickly near the hub. Haven't cut them yet. The pipe is sitting in my office on the radiant floor. Ought to be nice and warm. Now I just have to find my jigsaw... Used it last week in the garage I think.

[baggo]

Hi Peppyy,

Haven't progressed any further with that project at the moment. I still want to try a three phase stator for it as the single phase is very 'lumpy' when producing power. It's too small really and this makes it difficult to get a thin enough three phase stator. I am more interested in getting the small induction motor conversion flying at the moment to supplement my solar panels but I will get back to the dual rotor at some time. So many projects and not enough time!

John

[wooferhound]

 I have been thinking about how to make a 4 Blade PVC prop from 2 pieces, and was planning a more detailed post after I try to build a set, but I'll try a brief description.

 Was planning to make one (two blade) prop the standard way where the hub is about Half Round. Then make a second prop where the hub has an area where the pipe is full circle. Then cut through the side of the second (full round) hub in such a way that the first prop will slide in there and bolt to the genny with a single bolt.

[Jerry]

The cars you've mentioned should have 3" daimeter magnets. The actual magnet will be about 3/8" thick. These disc magets will sometimes fit in car alts and will replace the rotor coil.  However its a real weak alt after conversion. Worth expirimenting though. I did a for alt this way.

I put the basket part of the speaker in the vice. It crushes it a bit but thats ok. Then I take a fairly shart chizel, place it between the magnet and the backing plate and give it a quike rap with a small hammer.

Most of the time the backing plate just pops off. Sometimes the magnet shaters or a thin uneven layer of it stays on the plate.

If the plate comes off clean I'll pop the magnet off the top plate same way.

I've got quite a stack of good magnets. My new tile cutter wet cuts these magnets real easy.

Makes nice pie shape segments.

Most of the backing plates have holes that can be drilled larger if need be for larger shaft sizes.

These backing plates work great for blade hub supports. The big ones make nice small alt discs.

                      JK TAS Jerry

[nothing to lose]

I'll try taking a few apart in a day or two,  thanks.

I seem to have ran out of wind here, right after making changes to the test mill.

 I maybe taking them apart while I wait for some wind now.

[nothing to lose]

I have a normal 2 blade set, and a shorter 2 blades only mounted on my mill now for a 4 blader.

Last night it was spinning so fast the blades were a blurr, I think I measured around 50V open. Running 2 phases into a 35amp rectifier connected to a 12Vdc fan though I got mostly 4-6Vdc and highs around 11v I think. Fans starts running slow around 2V. I think  durring the night I could have put a little juice in a 6V battery, probably very little. Under load I got a pretty good bit of 6.5Vdc-9Vdc off the 2 wires. It did move some hot air from the wood burner at least.

The altenator I had out I was going to rip apart for diodes turned out to be my big Ford 100 amp instead of the GM I thought it was. I was in a hurry and grabbed it without looking at it. Why it was sitting where the GM was supposed to be and where the GM actually is I don't know now. Hadn't touched these in years, and I know where I tossed them last time still!!

 So I only had one rectifier for 2 wires and used it for what I could. (Nothing is open here on sunday, only noon on Sat, and I didn't want to drive 50 miles each way to where they would be open)

 Shorting the mill stops it to a slow turn.

I wired in a 100' extension cord and run the AC to the living room where I could play next to the warm wood burner watching the mill out the window. Probably some line loss too.

 I think it got around 17Ftemps and high winds around 1AM or so.

I did not see any bad blade flexing occuring and they stayed on the mill so far.

[Peppyy]

Before you say it....I Know

I only have a #20-4 wire running from my ametek, doubled but I just wanted it to monitor voltage. Now I have an 8w Fl trouble light on it too. I added a 12v (L7812C) regulator on the light since I have a bunch of them. I am planning on picking up a #14 50' cord at Wally-World next time I get to town.

Haven't had a chance to cut my blades yet. Might be a good day since it's -5f and windy out today. Thought I might build a new tail for it too. How does a bunch of LED's in the shape of a star sound? Think my neighbors would like it.

[nothing to lose]

Every one steals my ideas before I tell them what I am thinking

I put a cheapy small red reflector on my blade as a weight when I balanced it. Can shine light at night and see if blades is turning easy, but only when the mill is facing me!

I am thinking when I put up the final working mill and new tail ect.. I may take a 3Vdc motor (race track type) and mount it, blade, and a few leds on the tail. Then I can look out and if the tail is lit I know the wind is blowing. Kinda a mini-mill on a mill

Probably the simplest way above.

Or I may take a cheap small solar cell to charge a little battery on the mill and use a simple switch to detect when the blades are turning to light the leds.

First I have to get all the bugs out of my mill though before I worry about dressing it up nice.

[Peppyy]

Mine are hooked up to the output with a current

limiting resistor. They draw such a tiny amount

of power that I don't worry about them. You could

always use an IC type regulator if you are concerned

about over voltage. I just use a higher value resistor.

I had some snow on mine last night and the green led really lit that up.

Today I brought it down to change the prop,(Single ZubWoofer)

 and mounted the green one tight to the edge of the plexiglass tail.

Of course as soon as you make a change the wind stops blowing.

I think I have come up with a design to mount both Zubs together

without loosing any strength. I have to find a bandsaw that

will handle 4" stock or a 4" hole saw. I am planning on making one

piece that will conform to the front of the inside blade and the back

of the outer blade.

I don't know if I can explain what it looks like,

for that matter I don't know if I could draw it either