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Signing UpStep 1Marking the pipe
The first thing was to mark out the pipe.
I first used a length of angle iron to mark a line along the pipe, by using angle iron you get a perfect line and all your lines will be parallel.
Once the first line was marked i measured the circumference of the pipe and devide it by 3 to give the spacing for the other lines. I marked the distance on the back of the tape measure so i could wrap the tape around the pipe for a more accurate mark.
Once you have the equal distances marked use the angle to mark a lines.
I first used a length of angle iron to mark a line along the pipe, by using angle iron you get a perfect line and all your lines will be parallel.
Once the first line was marked i measured the circumference of the pipe and devide it by 3 to give the spacing for the other lines. I marked the distance on the back of the tape measure so i could wrap the tape around the pipe for a more accurate mark.
Once you have the equal distances marked use the angle to mark a lines.
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I thought that the tips would be narrower as the further from the center you get on the blade the faster the blade is moving the center may be going only a few mph but the blade tip is going closer to 100 mph
It would also put all the weight to the end of the blade, not really where you want all the weight in something spinning at speed.
Also , why do all commercial wind turbines have blades with narrow tips? Its best to copy an idea that is know to work.
On the subject of the shape of the blades, you almost hit the nail on the head on your answer above. The real object of the blade, be it powered as in an airplane propeller, or a helicopter rotor, or wind driven like in your blades, is to have the air pressure equal along the length of the blade. The tip speed is greater so it is narrower and flatter, producing X power. As you take power measurements closer to the hub, the blade in that spot is turning slower relative to the wind and the blade is pitched more, thus producing the same power as at the tip. The same is true at all stations along the blade.
Now if I could just find what diameter and thickness of pipe you started with.....!!
I think 1mtr is a little to long for this, I had planned to cut them down to about 18-24" and re balance them, bad health etc stopped me from taking that experiment any further, but as the Ible says it was only a prof of concept and I hope that someone out there has taken the idea to the next level.
The home made plastic pipe blades have a decent enough pedigree on small scale turbines from the research I did, they will break in high winds but then this is a safety feature of sorts as its better to have the blades that cost a few pennies snap than kill your whole turbine.
Most of the stuff i found online was for pipe blades of about 18-24" for small portable turbines.
Good luck with your own experiments.
Also in power production higher speed gives more power.
Watch the movie, and you will find that you can tell when lightning is going to strike and that lightning is not the only power source capable of producing 1.21 giga watts, a Mr Fusion machine can, but then that will not be invented until 2015.
Perhaps if you had read the instructable rather than the comments you would have seen the bold type that said that this was just a proof of concept project to see if the reclaimed casting could be used to build a functional rotor for a HAWT
The purpose of this instructable was to show other people who dabble with homebrew power how to use reclaimed parts to build a simple yet effective rotor for almost no cost.
http://www.youtube.com/watch?v=bnqtXOi1iaY&feature=related
The "be nice" comment policy stopped me from replying to that one how I would have liked to. ;-)
I'm glad to see that some people actually do think outside the box and dont limit them selves to what the science books say.
It is possible to use a standard motor if you replace the electromagnetic armature with permanent magnets, not the most efficient way but its a start. I have one of those direct drive motors featured on your link that I may use on a HAWT at some point.
I'm in a state of project overload at the moment and the shed also needs cleaned out to be honest before I do anything more. This was purely a proof of concept thing and will most likely stay on the back burner until the rest of the parts for the build show up.
I want to finish the VAWT project more than anything as there are just to many safety issues with HAWT systems that I am less than keen on.
PVC will also fail sooner than aluminium, I don't mind the fact that the PVC blades will fail if the wind gets very strong, I would rather replace a cheap blade than have a metal prop spinning out of control.
Aluminium is harder to work and is x amount more dangerous to have spinning at several hundred rpm. to add pivots or flexible joints makes the build to complicated for most diy guys.
I work on the KISS system. Keep It Simple Stupid. I am trying to design a no cost or ultra low cost wind turbine that can charge a few 12v batteries and run a few low power devices. I want something that McGyver could knock together with only his Swiss army knife.
I chose PVC pipe as it already is a a tried and tested method, and also for the fact that it WILL FAIL in high winds, its better to replace broken blades than to rebuild your whole rig.
I'm using cheap easily worked PVC because I know it will fail in high winds, from the info i have seen on other peoples use of PVC pipe I have gathered that some like the idea of having a failsafe built in to your design especially when you are doing a first time DIY build from salvaged parts.
Please remember that this is Instructables not NASA that most of the DIY guys don't have bottomless budgets and fully equipped workshops.