Turbine Construction Progress

[kitestrings]

Boond,

Looks great!  Is that the Clark profile?  It is much more symmetrical then I'm used to seeing (other than with folks here).  It looks like you've borrowed from Chris' formed-lexan cover for the alternator.  Was that challenging to shape?

I agree, but disagree with Adam -

It is an awesome looking build.  Agreed.

I think the inner third, in general - and spinners in particular - get a bum rap here.  First there's the all-important aesthetic piece, which is that a turbine just plain looks better with a spinner (IMO).  The spinner also offers weather protection for the blade root-ends, bushing and hardware.  And, in the case of a variable pitch mechanism, I think this is a critical component.  I'll concede the aerodynamics benefits may be minimal at best.

I know I'll raise some response, but I think the 'inner-third' is written off largely because it has been said here before, and repeated, without the conlusive evidence to support it.

Anyhow, keep up the great work.  Look forward to seeing it up.

~kitestrings

[midwoud1]

Hi Boondocker.

That is a high class machine. The blades look like NACA 4415 . Did you have a special reason for it ?
Do you have a special coating on the blades ?
Great work . Looking forward to see a video when spinning .

I have a windmill with a spinner but that is to protect the pitch mechanism against rain and snow.

    - Frans -

[Boondocker]

The air foil is S822.

http://wind.nrel.gov/airfoils/shapes/S822_Shape.html

[Boondocker]

The bonnet is not Lexan or plexiglass, I was concern that it would act just like a large speaker cone.  I used a piece of PVC curtain strip instead.    The curtain strip is soft and shouldn't resonate the vibration, but still is rigid enough to hold a shape over a short span.

Haven't given a nose cone much consideration, will put my efforts else where for now. 

[Boondocker]

Midwond1,

A S822 foil was chosen because it has been well research.   I plan on carving other foils after evaluating these.   The coating on the blades is a POR15 product:

http://www.por15.com/METAL-MASK_p_40.html

[Boondocker]

[Boondocker]

Up it goes

[kitestrings]

Awesome Boond!  It looks great.  Hope it works  well.

~ks

[Boondocker]

Here are videos of it first running.  The turbine cuts-in at 5 to 6 mph and easily seeing 150 watts at 10 mph.   
http://www.youtube.com/watch?v=eRZflhCdcVs
http://www.youtube.com/watch?v=KZFyrRIpNWg

Will be making some furling and tail angle adjustments, it takes a stiff wind to get the blades flying.  Once spinning, they will hold at 48v (cut-in speed) with a light breeze and begins producing power at 5 mph.   

Spending some quality time with the Midnite Classic controller, it is a real nice piece of equipment.  I'm having a lot of fun making adjusting the wind tracking curve.  As of now, tweaking the curve based on feedback sound of the blades.  In one of the videos, a clunking sound is heard and then the tail momentarily rattles, believe this is occurring when the Clipper is active.

[upstateman]

Interesting.I see the tail was getting beat pretty good.The winds must have been gusty and changing direction rapidly, or something was causing the wind to be turbulent.

[tecker]

Little more weight on the tail maybe .You've made a really  nice machine

[kitestrings]

I looks to me like the tailvane is just twisting, flexing between the upper and lower supports.  Maybe just a strut, or brace of sorts?  Looks great overall.  ~ks

[Boondocker]

KS

Thanks, but my build isn't as eloquent as your turbine.  Will you be using a Classic Controller? 

Great day for wind. 

http://www.wunderground.com/history/airport/KSJX/2013/11/4/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA

[kitestrings]

Yes.  We have 2- Classic 250's.  Eloquent, but still unproven.  I'm sure will have some things to learn.  Hopefully not all the hard way...

Great weather data.  The station is close to your site?  Looks like perfect winds for getting some feel for the thing.  Have you gotten the output curve where you're somewhat happy with it?  It's got to be an exciting, nerve wracking time as you gain comfort with things.

Post your observations as you can.

Best, ~ks

[Boondocker]

As for the wind tracking curve, I started out with the points published on Dairy Land Wind Power.

http://dairylandwindpower.us/Classic150_PowerCurves.html
DWP350N20P-24V TSR6

Using this curve as a reference, subtracted 2 volts, except for the zero amp point at 48v, since the rotor is larger 12'.   I've yet to get the data logger going to do any determination if the curve is optimum.

 What I've observed so far when the blades start making a “swooshing” sound, more power is produced at that rpm. There is a slight growl sound from the alternator heard coming out of the tower when it is taking a larger pull of power also.

I made a change a pitch to the blade because the turbine wasn't spinning up to speed in low winds.  It was taking 14mph wind to get the turbine flying, kinda like taking-off in an airplane with the flaps-up.  Originally, the pitch at the tip was at -3 degrees.    Now the tips are at zero degrees, and the turbine will comes-up to speed at the lower wind speed at 7 mph.   Once the blades are up to speed and flying, it will hold at 48v rpm until the anemometer stops spinning.

[Boondocker]

I made two cross member braces used on the tail vane.  One out of aluminum to keep it light for easy furling and the second out of steel.   The aluminum one didn't last very long. Replaced it with the heavier steel brace.   The extra weight did help steady the tail.


Along with the turbine, the electrical panel was also upgraded.  The wire trough on the bottom keeps wire runs tidy.