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Catch66
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Joined: 13/03/2010
Location: United States
Posts: 27

Posted: 07:41pm 03 Dec 2011

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Good Morning all,
Well we have had some extreme winds here in Northern Mt.
I live close to the East slope of the Rockies. 70 mph of lately
with hard gusts.
So this morning during a slack in winds I pulled unit down.
My fears were found the 5 blade prop had developed a crack
from around bolt entry.
Some time the gut instinct..pay's off.

Any how curious this prop is 51" It mic's @ .085" its maker stated
tested.. 85 mph+.

What thickness is common in Aluminum blades used on your units.

Thanks,
Chuck

Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5078

Posted: 11:25pm 03 Dec 2011

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Hi Chuck

Is it the "flat sheet of aluminium bent into a blade" type of blade, usually rivited or bolted to a steel spar? Also, whats the approx diameter?

If so, though they seam to perform well enough for normal wind conditions, in your situation of strong gusty winds, you may be better using a different blade. The problem with aluminium is flexing will cause it to crack and fail before other materials, like steel or wood.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

Catch66
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Joined: 13/03/2010
Location: United States
Posts: 27

Posted: 12:09am 04 Dec 2011

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Thanks Gizmo.
Flat sheet with angled bends..51" o.d.

A question I have not seen metal steel in the tube type blade.
TLG has a nice looking blade which are .125" but is aluminum.
wood is probably out for Me.
#1 priority is noise then performance.
I must say I'm really disappointed with the angle bent glade.

Chuck

Gizmo

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Location: Australia
Posts: 5078

Posted: 12:59am 04 Dec 2011

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Hi Chuck

Blades that make excessive noise generally have something wrong with their profile, not the material they are made of.

The GEO222 profile is a popular choice with this web site, you can buy the blades in wood , PVC or aluminium. They run quietly and have lots of torque. You can also make you own timber blades with a chainsaw! Results are pretty good.

What alternator are you using, and do you know what RPM and or wind speed it needs to reach cut in speed ( starts charging the battery )?

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

yahoo2

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Joined: 05/04/2011
Location: Australia
Posts: 1166

Posted: 05:02am 04 Dec 2011

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I have installed a windy nation 3 blade hyperspin on a faulty air-x with no speed control, these blades have copped some extreme high wind and seem to be holding up. they are a .125 inch thickness pressed curved blade at 58 inch diameter. The company recommends no more than 40mph without furling or electrical braking. I think the 5 blade models don't handle the high wind speeds as well and tend to stall a bit.
I was worried about the mounting holes myself, so I radius-ed the hole edges, used a larger and thicker washer on the top and tightened the bolts with a torque wrench.
they don't spin as fast as the air-x blades but are very quiet. I lengthened the tail to stop the blades waggling in turbulent air.
I cant comment on the power producing abilities of these blades as the owners are in no hurry to let me fix the turbine fault. The air-x blades they replaced would continuously cycle over-speed, brake, over-speed, brake and howl like a 9 inch angle grinder (when the genny worked).

cheers yahoo

I'm confused, no wait... maybe I'm not...

Catch66
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Joined: 13/03/2010
Location: United States
Posts: 27

Posted: 09:25pm 04 Dec 2011

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Thanks Gizmo & yahoo2
first Gizmo I have run a Ametec 30 for almost a year now,geared 3 to 1.while testing main pole, guys and Furling.
But to go up a rewired F/P 36 pole with 3 coil groups...purchased for Randy here in states. battery voltage holds @ 12.9 or higher,up to 14.4vdc then Morningstar 45 begins to dump excess.

Living in town noise is a #1 priority along with safety..
I somehow do want to add a tachometer.to add speed monitoring.building from the bike unit in a post that had a reed sensor I believe,might try..

The link to the Aluminum blades my..my what precision and time in building these fine blades must of taken.very very nice.

yahoo2 I've seen the blades you mentioned but found no info. On diameter thickness. thanks for sharing that info.they do look nice..I did like the early start up with the 5 blade I purchased.
I must say that this is only a hobby, but the most enjoyable one I've had in Years..

Thanks to you both.
Chuck

Catch66
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Joined: 13/03/2010
Location: United States
Posts: 27

Posted: 10:46pm 04 Dec 2011

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yahoo2.
I reread your comment, my space in town yard is limited as to where
I set my turbine pole.
SO I also have turbulent winds what length are you using for tail..
While I have it down I have a # of better ideas to attack..
Thanks Chuck

yahoo2

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Location: Australia
Posts: 1166

Posted: 04:46am 07 Dec 2011

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Hi Chuck,
The Air-x has tiny stumpy tail designed by the marketing department and accountants to fit in the box, save freight and look trendy, so anything is an improvement. I generally make tails by eye, if I had to put some numbers on it, tail boom should be longer than the length of one blade on the rotor (that is half the diameter of the rotor)and the tail plate measures more than a third of a blade length in height. Probably a good starting point.

My opinion is the GEO222 is a far better blade than any of the pressed aluminium jobs. At certain revs the windy nation gets very "twitchy" and needs perfectly smooth air to keep its speed up. I would guess it is only the tips of the blades that are flying and creating lift, any little air pocket will make it loose lift on that side and buck around, then it will take 5 seconds or so to get up to speed again . The GEO222 seems to create lift over more of the blade in moderate winds and looks a lot more stable.

If you can sneak a few extra feet of height and get some clean air, it makes a huge difference to your power output over a year. Where I live, I test turbines in a spot with no trees or houses within at least a mile and I still get dirty air under 30 feet, on a hot day. On a 18 foot pole I can hear them clawing and slapping the air, but the times that I made the effort and erected the 60 footer, they just purred like a kitten. I attach a few streamers up along a test tower to see how high I need to go to get above the bad turbulence when I am assessing a new site.

yahooEdited by yahoo2 2011-12-08

I'm confused, no wait... maybe I'm not...

Gizmo

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Posted: 11:56pm 08 Dec 2011

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yahoo2 said The Air-x has tiny stumpy tail designed by the marketing department and accountants to fit in the box, save freight and look trendy, so anything is an improvement.

Well said.

Many of the cheap or "stylish" wind turbines have tails that are too short. A small tail fin on a long boom is more stable and will follow the wind better than a large tail fin on a short boom. Its about the leverage and turbulent wind behind the turbine. Adding a dovetail or kicker to the tail can help too. The tail of a wind turbine is not like the tail of a aeroplane, we dont care about drag, but we to want it to have good leaverage against the nacelle. On a 2.2 meter turbine I ran a 2 meter tail boom, and it followed the wind very well, plus furling was smoother.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

Catch66
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Joined: 13/03/2010
Location: United States
Posts: 27

Posted: 10:16pm 17 Dec 2011

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Hello, Wind as usual to day..
wanted to give you both a update.

I talked with Terry @ TLG ordered a Boast buster 3 blade prop.

It has a root of 8" at base. Will let you know how it turns the F/P.

I hooked the F/P up the other night to a battery and rectifier with
Dc amp guage. With a spiner wrench I saw 4.5 amps not sure of speed.

then I tested the dbl. throw HD Switch wired in before rectifier
1 lead to each side the other connected below flipped to the on position
yep very hard to turn. so Stop switch works.

Take care..From windy Montana
Chuck Smith

VK4AYQ
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Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 11:46pm 17 Dec 2011

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Hi catch 66

When you set up permanently make sure you put some resistance between phases on your stop switch as a dead short directly across the alternator could damage it or some part of the wiring, if you have increased the drive of the Propeller and its weight and therefore it's inertia this is particularly important.

All the best

Bob

Foolin Around

Catch66
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Joined: 13/03/2010
Location: United States
Posts: 27

Posted: 06:17pm 18 Dec 2011

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Thanks,VK4AYQ

Thanks for the useful Tip info.. What is A commonly used Resistor.

In fact I'm wiring the 3 phase to switch today.
Another windy day +20Edited by Catch66 2011-12-20

VK4AYQ
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Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 11:33pm 18 Dec 2011

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Hi Catch66

For a small mill I would use some nichrome wire available at electronic suppliers, I have found that two strands wrapped together a foot long between each phase works ok on mills up to 300 watts,if your mill is still down you can rig the resistors and then do the wind test to feel the loading compared to a dead short.

All the best

Bob

Foolin Around

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