Author Topic: some pics of my Piggott 4' (Read 7352 times)

defed · « **on:** August 02, 2009, 10:34:52 PM »

figured i would post some pics of my Piggott 4' machine in progress.

here is my stator. had a bit of trouble w/ it...you can see some internal air bubbles, and some pop marks on the surface.

i made the connections to some brass bolts so all connections were inside the casting.

here is my magnet disk, a brake rotor.

i used a rear wheel spindle from a front wheel drive car. i had to machine the hub a bit to fit my rotor.

here is the frame, minus the tail and yaw pipe.

being put together for testing...

plenty of small problems along the way, but it's coming along, and so far it works as it is supposed to!

Dave

defed · « **Reply #1 on:** August 02, 2009, 04:39:22 PM »

yes, i know my welding is terrible! for the important ones, i tack it, and i have my dad finish it, he is MUCH better than i am.

Jerry · « **Reply #2 on:** August 02, 2009, 06:02:00 PM »

Hi defed.

Its great to see anothers work building the Hugh Piggot 4ft machine.

It looks as though you've been doing much work.

I'm abit confused by your coil and magnet orentation. I've not seen magnets and coils set this way.

Normaly magnets and coils are set pointing outwards from the center?

I'm sure thats how its described in Hughs book. I can't confirm that now, a freind has my book.

I would think this orentation would reduce power output with the magnetic lines of flux cutting accross the smaller part of the coils.

However you say your test #s are on trac? Can you laithe test with rpm, volt and amp #s?

I have done this plus prime driver power requierments as well.

Here are a couple pictures of how I think magnet and coil posistion was sugjested in Hughs book? I could be wrong?

This is the stator.

This is the magnet disc rotor.

I am very intrested in your complete test #s. Thanks for shairing.

Jerry

defed · « **Reply #3 on:** August 02, 2009, 06:55:44 PM »

the 4' machine is Hugh's book is as i have done. i asked about it before i started...

http://www.fieldlines.com/story/2009/2/8/235213/8286

so i just went with it.

it is a 24v machine.

here is the #'s from my initial testing. hook a volt meter to (any) 2 of the 3 phases. at 100 rpm, i get 6v. so, at 300 rpm (target cut in), i expect 18v. i then multiply this by the 1.4 to convert to DC...18v x 1.4 = 25.2v

subtract the 1.4v of rectifier loss to get total output of 25.2v - 1.4v = 23.8v

the recent discussion is here...

http://www.fieldlines.com/story/2009/8/1/05952/33772

i'm not sure how to test the amp output tho.

the 4' is more of a practice model. i'd rather make my mistakes on this one than a 10'...and i'm making all sorts of them! hopefully next time i will remember and not make them again.

brokengun · « **Reply #4 on:** August 02, 2009, 06:57:20 PM »

If I remember correctly those coils are the way pictured in Hugh's book. Why? I can't be certain.

I am working on a set of 4 footer blades right now actually. It's my first set of blades so I'm mostly doing it to learn and mess up without spending lots of money and ruining wood. I am kind of confused as to how to slope the front of the blades. I figured to just do a gradual slope from the marked drop line up to the leading edge but the photos in the book look different. Wondering what you two are doing for blades....

It is neat to see some 4 footer stuff, it's a pretty great summer project. I have been following Jerry's posts on his 4 footer stats. Although I don't know if I will make the generator this summer, I imagine I will make time for it soon.

What are you planning on for a tower or what are you mounting it on?

defed · « **Reply #5 on:** August 02, 2009, 07:05:18 PM »

yea, i'd rather try carving 2' blades 1st as well.

i am getting a 60' free standing tower. well, supposed to be. i had to wait until this coming week to arrange for a guy to help me pick it up, and i told the guy selling the tower this and he was fine with it. i haven't talked to him in 2 wks tho so maybe he sold it to someone else! i will post some info about the tower and blades when i get that far. i will probably only do 40' at 1st, and go higher if i need to.

kurt · « **Reply #6 on:** August 02, 2009, 08:38:52 PM »

hugh changed the 4' design in his latest book turning the magnets and coils sideways how he has it in order to make more room at the center for the hub..... that is what i have heard anyway.....

defed · « **Reply #7 on:** August 03, 2009, 01:55:13 PM »

when i was testing the output of a single coil, i should have rotated it and the magnets to see if the voltage changed. too late now, all my coils are in resin!

richhagen · « **Reply #8 on:** August 03, 2009, 03:58:26 PM »

Ditto what Kurt said. There had been a few comments on it here at the time if I recall correctly. Jerry, this is about when you would have been real busy with the rebuilding. Rich

brokengun · « **Reply #9 on:** August 03, 2009, 09:02:38 PM »

Maybe if I get to casting the stator this summer I'll remember to try that. I'll be sure to post the results of course.

Flux · « **Reply #10 on:** August 04, 2009, 02:06:54 PM »

Yes Hugh turned the magnets round on the later version to get more space in the centre of the stator for the hub. The original version had a strange bearing arrangement with the stator up front and the magnet rotor at the back. The new arrangement is easier to build.

There is not much difference with the magnets turned round, you are looking at flux linkage, don't get bogged down with this stupid myth about active and dead coil sides . This single conductor emf equation implies that long conductors passing the magnet have higher volts and it is true for a single conductor but when you make a circuit the whole thing causes infinite confusion. If you have a given sized coil and magnet the flux linkage is the same and if the angular velocity of the magnet is the same ( same rpm) then the voltage will be the same. The only thing that could be different is the length of wire in the coil and that will affect the resistance a bit but it is second order.

The magnets turned sideways gives a simpler and more practical solution but the old design has a very similar performance if you can manage to build it.

Flux

defed · « **Reply #11 on:** August 04, 2009, 04:37:13 PM »

started making a practice blade today....it sure gets confusing! i understand the beginning after you lay out the stations and start to cut the trailing edge (where it is flat surface from the new cut depth on the trailing edge to the untouched leading edge), but then when you start working on the backside, it gets weird. guess i will just cut it in the stages and see what happens!

they are tiny blades.

Jerry · « **Reply #12 on:** August 04, 2009, 07:12:06 PM »

Hi defed.

I just started my blade set yesterday. I know what your saying about the confusing back side.

I've been wiating for my cabinet maker (retail stereo store) to build these blades.

I havn't seen any thing from him yet. So I'm giving it ago. I'm just throwing a set together from scrap wood.

However I'm real surprized how well they look. I'm going to sand them down tommorow and apply some paint. After that I'll ballance them.

They look as though they'll do a good job. Hugh is a very talented man. His blade design looks real good in person. Even if I've built them LOL?

I'll post some pictures of the blades when finnished. After that~ as soon as I find time I'll run Hughs 4ft machine in the wind tunnel for finnal testing.

This 4ft wind generator may find its final resting place in a small off grid install in NE Washington state?

Please keep us posted with your project. A few pictures would be great.

Jerry

brokengun · « **Reply #13 on:** August 04, 2009, 07:39:57 PM »

I started carving yesterday..... I am facing the exact same problem you guys are. I haven't started the leading edge because of confusion. I'm going to just dive in and make it look right I guess.... We should all try to post pictures to see how they're looking. Mine might be slightly embarrassing, but it's a learning process!

Jerry · « **Reply #14 on:** August 04, 2009, 08:09:15 PM »

Hi broken gun.

Thats watt I did. I said OH what the heck. I grabed some scrap wood and thought.

OK here goese if this don't work these will make some fancy fire wood this fall.

Half way through I was thinking YEP fancy fire wood allright, but then they actuly started looking like blades and I thought HMMM? They might work?

Its amazing what a lot of sand paper can do? I had to fill some holes and gaps but hey thats what wood filler is for.

I've been using a Saws all, table saw, chizel, belt sander ECT.

Good idea I'll post some pictures hopefully tommorow?

Jerry

defed · « **Reply #15 on:** August 05, 2009, 03:24:11 AM »

i have to stop by the store and get some tools. i don't have a good hand saw or a hand plane. i do have a power plane, but i think a draw knife would be nice. something that would span the entire surface of the flat portions.

Flux · « **Reply #16 on:** August 05, 2009, 12:16:51 PM »

A draw knife is excellent. Hand planes are fine and a spokeshave is almost a must. If you can only afford one then get a convex one if you can afford it get a flat one as well.

A power plane is a mixed blessing, it makes too much noise and too much mess for me, I can't put up with it unless you get some bad timber that wont hand plane properly, I had to resort to one with maple.

If you can stand dust and noise then an angle grinder fitted with a very coarse grade sanding disc will do the job of the spokeshave and is more predictable than a power plane on the curved surfaces.

If you have nice timber there is a lot of pleasure in using hand tools, it is nearly as quick and infinitely less messy than power tools but I suppose it does take a while to get the best results from hand tools.

With very large blades then I am sure the chain saw approach is the way to go rather than making bin loads of mess with a power plane.

Flux

brokengun · « **Reply #17 on:** August 05, 2009, 04:54:10 PM »

Alright, I worked a bit today on my blades. I got one to pretty much where I think it should be... still needs some more sanding and some sort of coating. It's my first try carving blades and I'm not sure if I was following the directions correctly for the back side.

Here are a few views of what I came up with.

http://img43.imageshack.us/i/windwardface4footer.jpg

http://img91.imageshack.us/i/4footerprofileview.jpg/

http://img91.imageshack.us/i/4foottip.jpg/

http://img43.imageshack.us/i/4footerbladefrontvuew.jpg/

http://img29.imageshack.us/i/4footercladebackview.jpg/

Assuming I did it right, here is a good way to take off material from the back. Make cuts every inch and a half or so and stick a draw knife in between and yank off the excess wood.

http://img199.imageshack.us/i/cuttingp.jpg/

I mostly used a drawknife, belt sander and a small square power sander a handsaw was useful at times too. A spokeshave would speed things up a lot I think. I found myself taking out a lot of material with the drawknife which is easy enough but can be slow at times.

Does this look like it might work? Do you guys see any major places I may have messed up? Also, I think my wood was a bit too thin to begin with so the part the dips down on the windward side is a bit thin (about 3/16th inches).

defed · « **Reply #18 on:** August 05, 2009, 05:20:50 PM »

what size are your blades?

i started on mine a bit today too. i've seen the guy on the old fashioned wood working show use a hand saw and cut down a drawn line. i figured, that doesn't look so hard, i'll just saw down the line on the trailing edge and keep the saw at the proper angle to just ride flush on the leading edge. NOT SO EASY!

the power plane was giving me trouble, since i was trying to plane while maintaining the proper angle so as to not take any material from the leading edge.

the reciprocating saw actually worked the best, but still difficult. easy to lose your line and cut too deep. a bandsaw would obviously be even better, so i might have to use my dad's for the next piece.

the back angle coming from the root to the deep part was also difficult. it's such a small area on the 4' blade to get any tools into. i used a chisel, and it almost came out, but got a little steep on my angle.

a flat draw knife seems like it would be great for the front. nibble the material out and when you get close to the line, you could span from the trailing edge line to the leading edge corner and get a flat cut.

i didn't try the back yet. was going to try the recip saw again, but the blade is so thin, i think the vibration could break it.

brokengun · « **Reply #19 on:** August 05, 2009, 06:19:05 PM »

You're right a bandsaw would be the best definitely. Then just do the finish work with some hand tools.

I was actually surprised at how substantial my blade was, it is probably slightly thicker than it should be but not by much. I thought it was going to very fragile at the end but it is alright. I would be you can make it with a recip saw if your carful and don't cut exactly on the line. Give it some leeway.

Jerry · « **Reply #20 on:** August 05, 2009, 07:16:08 PM »

Well I started these blades 2 days ago. Outsiside of ballancing these are ready to fly.

I've even sanded them smooth and primed them and painted them with wight epoxy paint.

Here are a few pictures. In 1 of the pictures I set 1 of my nose cones on just for fun.

This is the nestled version.

I think I've come as close as I can to what Hughs design calls for.

Now maybe in a day or 2 I can get some wind tunnel test #s for the complete Hugh Piggot 4ft diameter wind generator.

Keep up the progress guys.

Jerry

defed · « **Reply #21 on:** August 06, 2009, 02:34:39 AM »

i found a PDF in one of my folders that basically says the same thing as Hugh's instructions, but has better pictures. i found it online somewhere, but not sure where, so if anyone wants a copy, i can email it.

Jerry · « **Reply #22 on:** August 06, 2009, 08:27:37 PM »

OK did a no load wind test of the 4ft blade today.

I still had my littel yellow 8" duel rotor alt mounted in the tunnel.

Hughs littel wood carved blades ran real smooth. It took a 1" stack of 1.25" washer for ballance.

A while back I tested my plastic "Jerry Blades" and some plastic pipe blades.

I tested them no load also and simply measured the voltage. All the blades were tested at 11 mph.

The littel 8" is a 24 volt alt. Here are the no load #s.

Pipe blades 30 volts.

Hughs carve blades 32.25 volts.

"Jerry Blades" 46 volts.

I hope to mount the complete 4ft Hugh Piggot wind genereator in the wind tunnel tommorow and do load testing fron cutin to the max tunnel speed.

I'll do this with all 3 blades and report the diferances.

Jerry

Jerry · « **Reply #23 on:** August 07, 2009, 09:48:08 PM »

Tested 5 diferant 4ft diameter blades today. I sugjest you take a look at the story.

Should be on the front page there some were.

The foam blades will get you more power. My blades will get you the most.

Jerry

Jerry · « **Reply #24 on:** August 07, 2009, 09:49:24 PM »

The story is under the Everthing collom.

Jerry

TomW · « **Reply #25 on:** August 08, 2009, 05:48:04 AM »

Jerry;

Here is a direct link to the blades test story:

http://www.fieldlines.com/story/2009/8/8/33037/45514

It should be showing on both "everything" and "Front Page" too.

Great to have your posts on these tests. Funny how one real world test can blow away hundreds of arm chair expert theories. And confirm some, too like the truck tests being inaccurate on the wind speed thing.

I still think the truck tests are fine for comparisons between units mounted on the same vehicle. Just cannot use the truck speed numbers directly as wind speed.

Great stuff.

Tom

oztules · « **Reply #26 on:** August 08, 2009, 10:17:20 AM »

Tom, " Funny how one real world test can blow away hundreds of arm chair expert theories."

I'm not sure your reading these results for what they are. Side by side testing of different blades on the alternator.

For me they don't tell me what I suspect you think they say.

To me it is just comparing different load matches in a limited range. I think you feel that it says more about the different blade materials perhaps.

As an example, if we double the wind speed, we should get 8 times the power if things are matched well.

If we look at his cut ins, and double speed we find interesting figures

For the foam blades we go from cutin to about double wind speed, and get 183 times the power...... for the Jerry blades, we get about 74 times the power instead of 8 times, the figures for the zubs is for 5.9 times (not enough figures to go further, but this still yielded 68 times instead of 5.9 times. Hughs blades in this setup from cut in to max figures should be 6.16 times, but was about 17 times. In this startup range we can expect a rough ride as we settle down to our design TSR.

So it seems to me to be a test of different TSR blades as well as materials. The big performers at cut in to double wind speed must soon succumb to stall.

From this I would say that if you only wanted low wind speed performance, then use very high TSR blades, and stall when the real wind turns up then no more power.... this is not as silly as it sounds....a very high tsr in stall at 15 mph, may not need much in the way of furling if the alt is electrically stiff???.

The real world testing of plastic fantastics that I'm aware of, seem to indicate that the real world power outputs are much better when the owners stopped persisting with the pipe blades etc and built modest wooden ones... but thats only small sample too that I know of.

Even the AWP down here with the chainsaw "emergency" blades kept up very well with the sexy glass originals. With a rewire, there is a big increase in power now. (from 23-4 to 30Amps@58-60v).. it is the matching that counts.

..........oztules

TomW · « **Reply #27 on:** August 08, 2009, 11:16:05 AM »

Golly, Oz.

You sure read a lot into one line intended to express how real numbers hold more weight than theories, however poorly stated, I admit.

I tried a few pipe blades in the early days but soon realized they were an entry level, easy option. Some folks claim great success with them but that was not my experience.

We all start someplace.

Hopefully my truck test comment holds water...

Tom

Jerry · « **Reply #28 on:** August 08, 2009, 09:06:57 PM »

Hi oztules.

Good points your making. As far as I know all of the blades except #5 have a tsr around 6?

I think this is what Hugh calls for in his 4 ft diameter genny. Correct me in any of this if I'm wrong.

My idea was to see witch blade worked best with this genny. My "Jeery Blades" have produced 1200 watts in some high winds. So I know they work well in high winds.

In these tests they've worked best at start up. Unfortunatly as of now my wind tunnel is limited to 12 to 15 mph depending on outside wind direction and speed.

I hope to make some improvments to top wind speed in the tunnel.

The other gennies I've been testing are also designed for 4FT blades with a TSR around 6.

I would love for some one else to build a wind tunnel and do the same tests I'm doing.

I'll even send them the stuff I'm testing just to see there results.

I welcome anyone to come over while I'm testing just to keep me honest.

I reports the #s I see thats all. You can make of them what you wish.

What I see is a group of blades and a group of gennies and the results of mods and testing.

Its not the materials that make these blades so difierand, it there shapes and airfoils.

I find the results intresting, they confirm my suspisions on designs and they help me dicide how I'll build the next wind machine.

Somebody build a better blade, well send it to me I'll test it. You know the genny I'm using just build it for that.

Well back to the lab more testing YA-NO.

Jerry

oztules · « **Reply #29 on:** August 09, 2009, 02:35:42 AM »

Hi Jerry,

It is/was never my intention to question your results. I am certain they are verbatim from what you saw.

You have given us a whole mess of answers/results. The difficult bit is to work out what is the correct question.

It would appear that the load matching is just wrong.... the wooden blade is far too slow for that alternator... why??

If they are all TSR=6, then ?..

.............oztules

Jerry · « **Reply #30 on:** August 09, 2009, 10:47:14 AM »

Hi oztules.

Yes it does seem so. This was the first blade I've carved. At first I thought it wasn't going to work. Then it started to look more like a blade.

When I finished the blade I posted the question to Hugh if the blade was correct. I understand that Hugh is a very busy man and most likely had not either read the post or did not have time to respond. I did think another blade builder would have checked the blade for correctness though.

I do have Hughs book and tryed to follow it to his instructions. It did fly very smoothly. I belive it is the blade Hugh wants the genny to be flown with. After all its his design.

I simply wanted to see how other blades wold work with his alt. I don't think Hugh would design the wrong blade for his alt.

Is it posable another blade might just be better? Thats what I think is not being accepted here.

I think maybe a truck mounted test would be in order here to see the higher wind speed results. That may change the results on Hughs blade conciderably. I would also love to test a blade built to Hughs specs by a pro wood blade carver.

Thanks for the over seeing of my work.

Jerry

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Author Topic: some pics of my Piggott 4' (Read 7352 times)