Author Topic: Need Turbine Blades or help designing them  (Read 6092 times)

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Cosmos275

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Need Turbine Blades or help designing them
« on: March 26, 2016, 09:53:40 AM »
Hey all.  I'd like to build a windmill in my backyard.  I've got plans to make it, but I'm stuck on the blades part.  This is mostly for an experiment (read: can't be huge).  I'm thinking blades in the 3 foot long range.  I'm a mechanical engineer and do CAD and I have access to a CNC machine.  That said, I haven't the slightest idea how to design a blade.  I'm thinking maybe I can buy some and get started that way, but I'm also interested in making the blades if I can get help designing them.  Can anyone recommend a book or anything that would guide me on blade design?  Or, does anyone know who manufactures smaller blades?  Thanks!

tanner0441

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Re: Need Turbine Blades or help designing them
« Reply #1 on: March 26, 2016, 02:18:05 PM »
Hi

The answer is simple.  Read back through some of the old post on this board. there are plenty of information from hand made to carving with a chainsaw. There are also articles on design and theory.

Brian






Mary B

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Re: Need Turbine Blades or help designing them
« Reply #2 on: March 26, 2016, 03:39:39 PM »
3 foot per blade is actually a decent sized machine! There are quite a few manufacturers out there plus as mentioned there are MANY blade carving articled on this site. Ebay has quite a few but don't go for the impossible snake oil specs that violate the betz limit.

Smithson

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Re: Need Turbine Blades or help designing them
« Reply #3 on: March 26, 2016, 06:25:42 PM »
Cms magnetics(magnets 4 less) are selling their 4 foot blades for 75.00 dollars off set of 3. You can get each blade for about 40. 00 dollars.they are great blades but don't expect them to send the hub with order.  They are on sale because they don'include hub and nose one.  If you can fabricate your own hub well worth the money.  A good wood blank would cost close to the 40.00 dollars alone.  Arch

SparWeb

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Re: Need Turbine Blades or help designing them
« Reply #4 on: March 26, 2016, 07:54:40 PM »
In case you are more interested in making the blades rather than buying them, I strongly recommend Hugh Piggott's website, www.scoraigwind.com.
Also:   http://www.scoraigwind.com/axialplans/index.htm
The projects there were the inspiration and information for me (also a ME) to get started.   I've had nothing but success with the blades I built.

Welcome to the forum, Cosmos!
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
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Cosmos275

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Re: Need Turbine Blades or help designing them
« Reply #5 on: March 27, 2016, 12:05:42 PM »
Thanks for the advice all.

I will dig back through the forum and check out the links you provided.

I may be able to make the hub unless it's some fancy 5-axis part. 

Smithson

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Re: Need Turbine Blades or help designing them
« Reply #6 on: March 29, 2016, 12:24:48 AM »
In case you are more interested in making the blades rather than buying them, I strongly recommend Hugh Piggott's website, www.scoraigwind.com.
Also:   http://www.scoraigwind.com/axialplans/index.htm
The projects there were the inspiration and information for me (also a ME) to get started.   I've had nothing but success with the blades I built.

Welcome to the forum, Cosmos!

Smithson

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Re: Need Turbine Blades or help designing them
« Reply #7 on: March 29, 2016, 12:36:25 AM »
My computer is doing strange things tonight.  I didn't'write that one post but it came up to post and I posted.  You can build a hub by buying a weld on hub (sprouket) from rural king or other web sites and welding it to a 1/4 inch mild steel plate.  Thanks. 

stofanel

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Re: Need Turbine Blades or help designing them
« Reply #8 on: April 15, 2016, 09:51:22 AM »
(1) What are the average winds for your area,

and

(2) What RPM range does your generator require?

Cosmos275

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Re: Need Turbine Blades or help designing them
« Reply #9 on: April 15, 2016, 10:01:57 AM »
I'm in Iowa where all the tree have been cut down   >:(, so strong winds.  I'm not going to use it with a generator.. different application.  I need to find out if code will let me build it in town to start with.

stofanel

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Re: Need Turbine Blades or help designing them
« Reply #10 on: April 15, 2016, 11:11:50 AM »
The reason I am asking about wind speed and desired RPM is because it affects airfoil choice. Also, what kind of torque/power do you require out of this contraption. These are important design parameters.

Cosmos275

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Re: Need Turbine Blades or help designing them
« Reply #11 on: April 15, 2016, 11:14:10 AM »
contraption indeed !!  I'm not really sure.  I don't have those numbers yet.  I would guesstimate not overly fast rpm and high torque would be good.  Thanks

stofanel

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Re: Need Turbine Blades or help designing them
« Reply #12 on: April 15, 2016, 04:54:15 PM »

Adriaan Kragten

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Re: Need Turbine Blades or help designing them
« Reply #13 on: May 16, 2016, 12:32:48 PM »
The theory how to design the blades of a wind turbine is given in my report KD 35 which can be copied for free at the menu KD-reports of my website www.kdwindturbines.nl. It is adviced to also use report KD 196 with questions and answers about each chapter of KD 35.

kitestrings

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Re: Need Turbine Blades or help designing them
« Reply #14 on: May 18, 2016, 08:13:36 AM »
Hugh's blade calculator is good.  I've found it to be cleverly hidden on his old webpage near the bottom; look under "Quick links to older stuff". "Blade Design Spreadsheet".
http://www.scoraigwind.com/#older
I also like Alton Moore's.

Here are some links that might be of interest/help:

http://www.alton-moore.net/wind_calculations.html
http://www.windstuffnow.com/main/blade_design_help.htm
http://www.scoraigwind.com/download/windrotord.pdf
https://www.warlock.com.au/tools/bladecalc.htm

I think some folks here have also purchased blades made by Royal Wind (Wind & Sun).  Last I knew there was also a fellow on The Back Shed making, selling extruded aluminum blades.  Aluminum wouldn't be my first choice, but he's been at this quite awhile and appears to have some interesting designs:
http://www.thebackshed.com/forum/forum_posts.asp?TID=8292&PN=1

Making blades is not the hard part.  A lot of folks seem to start there, which may be getting the cart before the horse.  It is getting them suitably matched to the alternator and design parameters that is the challenge IMO.

Good luck, ~ks

Gadget047

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Re: Need Turbine Blades or help designing them
« Reply #15 on: June 02, 2016, 08:39:56 PM »
I have designed a blade based on the 10' windmill plans on this site. I will upload the STL file. Your CAM program should be able to scale it down from 5' to 3' fairly easy. I created the design in FreeCAD (a great free CAD program). If you want to edit the FCSTD file you can do it in FreeCAD. Let me know if you want the FreeCAD file and I will attach that here too.
Dan

stofanel

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Re: Need Turbine Blades or help designing them
« Reply #16 on: June 03, 2016, 10:21:24 AM »
I am in the process of designing and carving my own turbine blades. I'll post some pictures and a keep you posted on the progress.