Will the Lift from Prop try to up force or Down force

[Catch66]

Hello any information welcomed.

facing prop will it rise up vertically or down.

Anyone having info on diam. of prop and the amount of force generated,by various wind speeds and its relation to weight lifting capability's.

[CmeBREW]

I think it depends on whether you are coming or going. (kidding)

You don't give enough info.  -- Are you asking about FURLING for a downwind turbine?

You can furl it upward, but it usually comes crashing back down too hard without some kind of a complex shock absorber set-up.  You can't furl down since the blades will hit the pole. You can always furl sideways with a mechanism and a spring.

The small down-wind mill I am trying to make know has NO furling. When a hurricane comes around I will just short it stopped. Simpler method.

Give a little more info. and others can comment.

[Catch66]

Yes, I had in mind using a absorbing shock, with a maximum stop mechanism,to allow 45 Max degree tilt. then when it returned after using force against absorber(to rise) it would cushion resetting. the Generator would be hinged in the front( like a tetor totter). this will not be  a 360 degree pivoting system. due to my area.

But I do not Know if blades can lift up if properly balanced on hinged over pivot point.Or can lift up at all when in High wind.Reason I decided on a rear prop turbine design as My wind will not be clean and will cause a lot of searching for directions,

I felt after watching videos of front wind turbines reactions to wind changes and that a rear design might seek much smoother.

I do appreciate your comments.

Hope this clears up a bit.

Chuck

[Ungrounded Lightning Rod]

The "lift" force of a turbine is along the axis in the downwind direction.  It appears as a force raising your tilt-furling machine only due to the offset of the turbine axis from the center of your tilt pivot.

You'll also have "nodding" forces from the yawing to track the wind, shifted 90 degrees by the gyroscopic action of the rotor.  (The same gyro action will also tend to make the mill yaw a bit as it tilts up and down from furling.)

These should be all you need to think about when designing your furling system.

[Catch66]

Thanks,

Ungrounded Lighting rod..

Now with a question about extended lay shafts.

with pillow block bearings to eliminate forces on generator bearing's.

Attaching 2 halves love joy couplings. they are rated at 3500 rpm and it will also extend my pivot point beyond axis (or pivot).with dial indicators can get perfect run out to prop.the (TEETER TOTTER) effect will be more or less as to how much weight I leave over pivot axis.

Chuck

[CmeBREW]

Sounds interesting to me. So you must be talking about quite a decent size mill--not just a 30" diam. toy like I'm messin' with right now.  

45 degrees is OK but will still be really going and putting a lot of tower load I think.  It only slows down some. Similar to a 45 degree tilt back furling mill.

Just a little idea I wanted to try but never got around to it yet,, is to use the swinging furling action (with dampener) to employ a 'Shorting switch' as it furls  upward thereby (seemingly) controlling it safer and far less tower loading.

Since I'm a cheap skate, I was thinking about first trying to short piece of copper pipe layed sideways up on the furling mechanism--and have it short with the brass (3-phase wire) connector bolt heads as it furls up. But the really big AMPS from a 12v big mill would probably melt it -- not sure. Maybe 24v system would be OK with less arcing??

Or perhaps a micro/magnet switch that controls 3 big amp solid state relays to short the coils during a big wind gust as it furls up. I believe the Skystream 3.7 downwind mill has NO furling and uses a 'shorting' method to control it in big winds.

From my little experience with my small 4' diam downwind mill, I would certainly put the yaw axis on ball or taper bearings. (or just use a trailer hub)

Downwind mills have a hard time turning (yawing) wide angles when stopped. Thats why I switched to the UPwind mills. (until I can make a downwind mill w/ball bearing yawing that is)

I would be very surprised if the Skystream 3.7 don't have a problem with that since it is a down-wind turbine with passive yawing. I presume it has taper bearing yawing for that 170lbs of weight.  But I love the looks of it I must say.

There is not much anyone can do with a stop-n-go, up-n-down turbulant location I'm afraid. I just accept the fact that there is only half (or less) watt hours per day myself. I keep my mill low to the ground to hopefully avoid the wrath of my neihbors. I hate having to do it.

-Good luck with your project.

[Ungrounded Lightning Rod]

Tilting 45 degrees gives you a cosine error on the wind direction equivalent to reducing the wind speed by about 30% and the wind power by 65%.  However if your load is resistive on a permanent magnet alternator the output power only goes down by 50%.

On a battery charging application the amount it goes down depends on the wind speed relative to cutin speed - and the higher the wind the less the percentage reduction.

In all cases I don't think 45 degrees lets it furl enough to avoid burnout in a storm.

If I were doing it I'd allow it to tilt back up to nearly 90 degrees, i.e. let it tilt back as much as it wants and just have a stop to keep it from flipping over rather than yawing if a high wind suddenly changes direction.

[Catch66]

Thanks,CmeBREW

No my project is of the smaller diam. too a little 30 volt Ametek.

I just live near some very High winds and want to build the safest and very reliable little generator. Maximum amperage is not of my highest concern in build. I just want my neighbors to say Hi in morning with a smile and maybe just maybe I can extract some voltage for heating water in tank.

I appreciate the input's on degree pitch. I will incorporate it into project.

Chuck

[Catch66]

Thanks, Ungrounded Lightning Rod.

I am getting excited about this now. With the information provided.

My next step will be the Voltage controller.

I would like to set up, to directly dump excess into 50 gal water storage.

Do either of you know of anyone making their own immersion heater's @ 12 volt.On this forum.

Thanks Guys you have been a great help.

Chuck