Archive for February, 2010

these pics are taken by me today on a modded HP Photosmart 850 camera thay are all taken in Infra-Red

HPIM1143c.jpgHPIM1144c.jpgHPIM1146c.jpgHPIM1147c.jpgHPIM1149c.jpgHPIM1151c.jpgHPIM1152c.jpgHPIM1153c.jpg

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propplan

On the upper left is the basic Template Drawing that I’ve been working and building off of. Lets design a 4 foot prop with a 25 degree Hub (or Root) angle, and a 7 degree Tip Angle for this explaination. The diameter of the pipe will determine the width of the blades. For blades that average 4 inches wide at a 25 degree hub angle, you will need a Pipe Diameter in the 10 to 12 inch range.

Cut your Pipe to 4.5 feet long. Draw a Centerline down the entire length of the pipe and accuratly mark the centerline on the inside of both ends of the pipe. This will be the Trailing edge.  Also mark onto the centerline the Center Point between the ends of the pipe. This will be the Bolt Hole.

Put the centerpoint of a protractor against the inside centerline mark on the pipe and find where the 7 degree point is on the inside of the pipe, make your mark there. Next find where the 25 degree point is on the same side of the pipe, and mark that point on the inside of the pipe. accuratly mark the outside of the pipe at these points too. Repeat this step on the otherend of the pipe.

The center of the prop is a circle (or oval) with the bolt hole in the middle of it. The outsides of this circle will be the same distance from the centerline as the 25 degree marks that you marked on the ends of the pipe. I would cut out a thin cardboard circle and wrap it around the pipe centered on the bolt hole mark and trace around it with a marker.

Turn a metal tape measure around backwards and lay it numbers down onto the pipe with one end lined up to the circle and the otherend lined up to the Tip Angle mark at one end of the pipe. draw this line onto the pipe, and repeat for the otherend of the pipe.

All the markings are done now. Since there are no cuts into the circle or through the blades you might want to erase or markout the areas in the center that don’t get cut. These areas are the dotted lines in the drawings above.

Time to start cutting. I think a Recipricating Saw works great. You can just cut straight into the pipe and get Good results. But if you angle the cuts as shown at the bottom of the drawing above, it provides a much longer path for the air around the back of the prop, improving efficiency. This is harder to do though because you want the cut to follow your markings as if they were on the inside of the pipe. You will see when you try to cut it.

Now you have a new PVC Pipe Prop that will spin like carzy in the slightest of wind.
Here is a picture af a 3 foot 4 blader prop experiment that I made from small 1 1/4 inch low pressure pipe . . .

pvc4prp1Hope this helps Ya’ll to make some cheap wind power.




Comments Comments Off


propplan

On the upper left is the basic Template Drawing that I’ve been working and building off of. Lets design a 4 foot prop with a 25 degree Hub (or Root) angle, and a 7 degree Tip Angle for this explaination. The diameter of the pipe will determine the width of the blades. For blades that average 4 inches wide at a 25 degree hub angle, you will need a Pipe Diameter in the 10 to 12 inch range.

Cut your Pipe to 4.5 feet long. Draw a Centerline down the entire length of the pipe and accuratly mark the centerline on the inside of both ends of the pipe. This will be the Trailing edge.  Also mark onto the centerline the Center Point between the ends of the pipe. This will be the Bolt Hole.

Put the centerpoint of a protractor against the inside centerline mark on the pipe and find where the 7 degree point is on the inside of the pipe, make your mark there. Next find where the 25 degree point is on the same side of the pipe, and mark that point on the inside of the pipe. accuratly mark the outside of the pipe at these points too. Repeat this step on the otherend of the pipe.

The center of the prop is a circle (or oval) with the bolt hole in the middle of it. The outsides of this circle will be the same distance from the centerline as the 25 degree marks that you marked on the ends of the pipe. I would cut out a thin cardboard circle and wrap it around the pipe centered on the bolt hole mark and trace around it with a marker.

Turn a metal tape measure around backwards and lay it numbers down onto the pipe with one end lined up to the circle and the otherend lined up to the Tip Angle mark at one end of the pipe. draw this line onto the pipe, and repeat for the otherend of the pipe.

All the markings are done now. Since there are no cuts into the circle or through the blades you might want to erase or markout the areas in the center that don’t get cut. These areas are the dotted lines in the drawings above.

Time to start cutting. I think a Recipricating Saw works great. You can just cut straight into the pipe and get Good results. But if you angle the cuts as shown at the bottom of the drawing above, it provides a much longer path for the air around the back of the prop, improving efficiency. This is harder to do though because you want the cut to follow your markings as if they were on the inside of the pipe. You will see when you try to cut it.

Now you have a new PVC Pipe Prop that will spin like carzy in the slightest of wind.
Here is a picture af a 3 foot 4 blader prop experiment that I made from small 1 1/4 inch low pressure pipe . . .

pvc4prp1Hope this helps Ya’ll to make some cheap wind power.




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