Tube Turbine

You seem to have left out some minor details. Such as how high you are planning on putting your funnel, end diameter of the funnel... It's all in the details.

How do you plan to turn the funnel to catch the wind,what is this going to be made out of,and how high off the ground,would it be square or round or what.With out knowing what you plan to build I would say atleast 1 1/2 steel scd 40 pipe in concreat in the ground, i'd say about 15 foot tall,atleast one on each side of the funnel.Or just frame it out with PT 2x4's.Sorry but don't know what you have or really what you mean.

Johnny

Problem #1 is that wind, when faced with the choice of constricting itself or simply going around what it perceives as an obstruction will simply choose the latter.

Problem #2 is that you're going to lose some of the very kinetic energy you want to capture when you make that right-angle turn.

Solution #1 is a little more homework before you make too many calculations. Try Paul Gipe's "Wind Power."

I thought about this idea many years ago when I was a kid but the obstacles you have to over come are not worth it.

The length of the funnel must be at least 4x the tapering i.e. 4x the difference between inlet & outlet else you'll get such a turbulence at the inlet that you'll get jack all wind going through.

Then the whole lot (funnel nd generator) must be able to turn otherwise you will get substantial drop in wind speed if you try to duct it from the funnel to the generator.

Last but not least, you are inevitably increasing the wind speed therefore you need a high speed turbine that must be well balanced otherwise it'll fall to pieces long before you know it.

The supporting structure must also be a virtual fortress due to the its high wind resistance of the funnel.

You think this sounds daunting? Wait until you go through all the nitty-gritty bits that I haven't even mentioned.

Ga from me.

This blog reminds me of the old joke:-

Question "How do I get to London from here?"

Answer "If I was going to London, I would not start from here!"

I must admit sheepishly I don't remember that 'old joke' but, if I try to understand it in my own layman way then I would definitely not leave for London, now, from where you are for sure.

Thanks for the info. My reasoning is to keep as much weight and all the moving parts on the ground. I was planning on using a steel pipe and funnel for the main structure. I was also going to incorporate a bypass system for high winds. My basic plan was a tube like a snake with a big head 15 to 20 feet in the air. The turbine probibly a squirrel cage style would be 2/3 of the way back. I live along a giant field and anly lose wind when the corn is high in fall. I want to produce about 40 KWH's. I have a prestolite 36v motor model #4006. Is this suffeceint? Any more help would be greatly appreciated. Thanks for the intrest and feedback.

Motors are not good generators.

If it is a DC motor of a good design, where you can radially rotate the brush assembly relative to the poles, you can improve the output efficiency dramatically by moving the brushes to the point where or monitor the output voltage/current for the highest output, or a simpler method is, where the least sparking is made when generating. (This is also the best position for brush and commutator life expectancy.)

Check to see if the brushes touch the commutator at 90° or at another angle. If not 90°, you are stuck with a particular direction of rotation.....with 90° you can usually pick the direction that gives the least sparking (highest output) within the adjustment range....

It is possible to "Flash" the poles of a wound field DC motor to allow it to produce the opposite voltage output if needed.

If the motor has no radial brush adjustment possibilities, my suggestion is to make brush holders that are full adjustable, it will bring large benefits later.....

Usually, windmills are made to produce AC out by having strong permanent magnets in a DIY assembly (there are plenty of good web pages on the methods and design of such Alternators)....even if you only need DC for charging, as these lend themselves to a design without brushes and far less likely to wear out or fill up with carbon powder as the brushes wear down!!!

A few diodes will quickly turn AC into "lumpy" DC......good enough for battery charging.....with a suitable regulator.

Best of luck.....

Hi a. schade,

What you are talking about will not work unless you have a second funnel on the other side of the turbine! In fact it is much better to mount two funnels together at their smallest diameter ie, back to back, and place the turbine within the smallest dia, ie in the middle.

Spencer.

It is the same with a hydro-turbine, after the turbine runner (propellor) the draft-tube creates a lower pressure area by expanision of the flow (water/air/?), to recover the energy lost on the incoming funnel. This must be correct in size and shape and may need cross-vane to break a vortice if there is vibration, surging of the runner, energy output.