Switchblade WindGen Design - Request for Comments

[Matrix1000]

I've come up with a design that has quite a few flaws I'm sure but it looks kool

I'm using a ' 59" hornet' turbine on the back but not sure what I should do for the front turbine. I was thinking of using 3 replacement blades from and Air-X as they are smaller but I'm concerned with the how much wind they may block from the rear turbine so I may just get another set of hornet blades and cut them to size. They would be counter rotating so that should reduce the effect of power loss of the rear turbine caused by cavitation.

In my 'pipedream' the front generator is supposed to be for Low wind, producing 12+ volts at 3-5 mph so it can generate at least something when it is just breezy while the rear should start at 5+ mph and generate how ever much it can etc (suggestions welcome as for the rear generator size!)  

This thing will auto furl by the use of a flexible hub made from ? I'm not sure of yet. I was thinking of multi layers of spring steel, (like the stuff they use in the bottom of jungle boots) or perhaps Aircraft aluminum that would allow some flex in high/damaging winds. Also because the front turbine is further away from the yaw bearing than the rear, the entire body may, during high winds, turn to the side a litle bit reducing the blade angle also.

Another problem I havent figured out is, how to get power from both of them at the same time. For instance if in a 5mph wind the front 30 VDC servo is generating 12 volts and the rear is generating like 9 volts they would be not only different voltages but they would also be out of phase so I cant just wire + to + and - to - and use one set of wires down my pole. I guess I would need some sort of charge controller inside the body pipe? (suggestions welcome)

I don't know much about this as you can probably tell and this is my first try,  but I am pretty tough skinned so any comments/suggestions would certainly be appreciated.

Thanks!
Follow this link for a clearer picture

[RobC]

I could be wrong but I think if you put full wave bridge rectifers on both generaters and then wire + to+ and - to - it won't matter the diodes will prevent back feed and you will only need one set of wires

[eformx]

There is a project in CALIF. using multiple rotors, this may give you some ideas...

http://www.selsam.com

Rob

[Jerry]

Hi Matrix

Just a few of My thoughts. I own and fly both the AIR-403 and the Hornet. Neith one will be doing anything at 3-5 mph, ZERO.

You've sugjested the 403 blades in the front. The 403 blades are much smaller and as such will be the last blades to spin. The larger blade will be better at low  winds than the smaller. However Neithr one of these blade types are worth a Cr@#$%^&&(&^P

When it comes to low winds.

You can watch the 403 and the Hornet on the roof of my store/shop. While all the home brew gennies with Jerry blades are spinning in low winds the 403 and the Hornet are at dead stop, nota, nothing.

As per the rest of your machine it may work but those little 1" wide toy blades are a joke.

You said tell it like it is. Hope were still freinds? OH BTW good to meet you.

                               JK TAS Jerry

[Matrix1000]

Hi, and thanks for your comments

I was wondering if the reason that the air-x/hornet blades didn't spin at low speeds could be because of the torque needed to start them turning.

Do you think that a 30-50 vdc ametek would allow them to start at a lower wind speed due to the lower resistance of the smaller servos?

I do believe you are right about the low wind speed performance of these fancy blades. I my quandry is how to allow the front generator to reach operational rpm yet not make the blades so wide that they create to much cavitation for the rear turbine. (I know I'm trying to figure out an old hard to answer question )

I'm thinking Perhaps 3 modified jerry blades which flex at high speed (because there is no auto furl for the front turbine as yet) would do the trick without creating havoc for the rear turbine.

I'm kind of looking at the design of "Bravo II" marine drives where one prop spins one way and another prop, on the same shaft, spins the opposite yet the props still function efficiently as a model for the turbines. Though I'm wondering if that would create a lot of turbulence for the rear turbine. Perhaps I should go clockwise for both.....(perhaps thats something only experimentation will answer)

[Matrix1000]

Cool! Thanks!

I'm wondering if that little generator he uses is only good to use with those little small diameter blades. It sure would be fun to find a source for that type of dual hub generators, perhaps a little larger on for the larger blades, and play around with them rather than 2 separate generators. That way maybe I could stagger the front turbine with the rear turbine and get more power.

[RobC]

I can vouch for the Jerry blades. I was at his shop one night and there was virtually no wind yet the home brews with the Jerry blades were spinning. A good cheap blade that works very well. RobC

[drdongle]

As I was reading your post I was struck with inspiration. Instead of mounting the generators "for and aft" why not arrange them so that the the first low speed generator faces in to the wind. As the speed of the wind increases the furling device starts to turn it out of the wind simultaneously staring to turn the second high speed generator into the wind and eventually the low speed generator is completely turned away and the high speed unit had turned completely into the wind.

This would require mounting both units 90 degrees apart and a well balanced platform on which both would be mounted.

Carpe Vigor

Dr.D

[TomW]

Matrix1000;

I have two words and an idea:

Wind Shadow. Which will slow the wind behind the front rotor and create turbulence. Not sure if its a big deal or not.

The idea is a knock off of one Jerry proposed some time ago and adapted to this planform.

using something like a TDM as front genny with a smallish prop to provide field coil energy for an auto type alternator driven by a much larger prop  of high speed on the rear genny.

Done right the front blade would be fairly small and it could be self regulating since with no wind there would be no load on larger prop till the front one built up field current for the rear alternator.

Just one of the ideas I had which would probably require rewiring the auto alt.

T

[Matrix1000]

Thats a good Idea! Low and high wind speed performance all in one package.

[Matrix1000]

I was doing some testing and I found something very interesting!

I bent the hub in the back into a 'slight' cone and mounted my turbine blades.

when the turbine faces back like this < and the wind is coming from left to right the windgen yaws correctly automatically BUT when you turn the windgen around almost into the wind the blades catch it like a cup and it auto yaws and centers itself into the wind also . Now that I think about it thats how the big 3 bladed 10kw turbines do it. Not only that but it forces air down towards the main body which feeds more air to the small (now rear) turbine .. Cool!

[Matrix1000]

I'm not sure how you would do this exactly tho.

Off the cuff I came up with this but I'd have to give it some more thought.

[Matrix1000]

Good Idea!

It seems that I have severly undershot my generator output... seems a 30 VDC amatek is almost useless and a 72-99 isnt too much better. Seems to me a 59" dia turbine could power a much more powerful servo/generator...

Anyone have any suggestions for servo/generator/generators? I cant seem to find a source for actual 'generators' (without a gas powered engine attached) online.

[Matrix1000]

Hmm ...now that I think about it, the blade dia closest to the hub is larger so the large turbine would create a significant wind shadow also for the small rear turbine also...

[Gary D]

Matrix, perhaps a simple solution to harvest the few watts available in a 3 to 5 mph wind would be to put a voltage doubler y'd in the line? Then there would be no need for multiple rotors on the tower. I think Hirtvane (sp?) offered this possibility a while back, although I'm not at all sure how to do it. Just a thought on keeping it simple. Gary D.

[Jerry]

Hi TomW

Acctully my idea was to have a TDM genny on its own tower away from a sperate genny on its own tower.

The second genny was a car alt. The lower power TDM was to supply power for the car alt rotor coil or armature.

This was to do away with fiting the car alt with magnets and the TDM would make enough power for the car alt rotor coil.

                           JK TAS Jerry