Curious

While bow drive may have some benefits over stern drive, the ultimate in maneuverability, reliability and versatility would be a drive at both ends. this would allow the boat to turn 360 degrees in place (by facing the drives in opposite port/starboard directions). This would work best on tunnel hulls and catamarans specifically designed to accommodate such an arrangement. Forward facing props would be advantageous. A forward facing vane for prop protection from debris impact would be straightforward to implement.

 

Having more props is good for control and could improve efficiency as demonstrate by Volvo IPS. I think there is still room for improvement in efficiency.

My windmill is more compilcated then the one below but uses a more positive diplacement concept and requires less wind speed. It is more positive displacement because the wind is always perpendicular or near perpendicular to one foil. Most standard windmills do not generate any electricity untill the wind velocity is high. I was hoping that my windmill would allow us all to have a generator in our back yard. I once built one out of tinker toys and put it front of fan and it turned quite erratic as the foils swang in and out. I tried to come up wih a restraining system to limit the free swinging foils to smooth it out but could not come up with anything. I still think some means of connecting opposing blades could smooth it out.

 

"to have a generator in our back yard"
or a cake drum generator on the boat arch

 

OK what's a cake drum generator on the boat arch.

 

something eastically looking a bit beter than a windmill to keep the battery's charged, a solar panel would be bigger i understood

 

Ok, must perhaps say ive only seen a "cake drum generator" in my fantasy

 

Yipster - I'm understanding your name a little better all the time.

Your cake drum generator is very interesting, never saw that before!

My design is not nearly as asthetic but has less resistance on the side rotating into the wind. My blades would probably need be shaped different then a simple foil but still free swinging. 2 or 4 What's better?

I thought the thing on top of the boat was radar.

 

and with fishingrod holders

as you know symetric vertical rotors may need a little starthelp and need keep their concave side upwind. remembered reading something bout using a vertical vortex inside, thought about a parabolic inlet and first site i looked today has a story on it. yes thats probably a radar sending electricity out, my poor mans thought was inconspicious getting it in.

 

augmentor/scoop

The augmentor/scoop would have to rotate as the wind changed direction and that makes it more complicated then my design.
I still think my design deserves some review by someone that can calculate it properly.

If you do not want it in your back yard we'll put it on your boat and use it as a sail and to drive a prop, and to charge your batteries. We'll call it the cake drum generator and mount it next to the radar.

 

Paul, I thought I invented the vertical vane windmill in your diagram back in about 1980. I made a little model of it with vanes that were (I think) 4" x 36". (I could go measure, but I'm lazy) Four vanes like your diagram but the vanes were hinged about 8" from the axis of the frame. The model was mounted on top of an upright 2x4 about 15' off the ground for about 14 years until it had deterioration problems. So I had a lot of opportunity to observe it. As you suggested it would turn in very low wind velocities. I can't remember exactly how low but if memory serves me it was in the 6 to 8 mph or thereabouts. It also was self limiting as to rpm. I also don't recall now exactly what that rpm was, but I am pretty sure it was less that 60 rpm. I do remember that for the bulk of it's speed range I estimated (rather accurately) that the speed of the hinge was about half the speed of the wind. In order to try to estimate the torque it might apply to the shaft at various points along it's path of rotation, I demounted three of the blades and measured the force generated in front of a fan with little weights tied to threads and passing over a little pulley. In this way I could graph the resultant force of two opposing vanes. The vector diagram approxiamated a morphed figure 8 which luckily didn't approximate it so much that it ever got to zero. I concluded that six vanes would make the graph very smooth but thought perhaps five would be better in case aerodynamic interference became a problem with six. This windmill has two very positive virtues; the self limiting speed and no bird would ever be killed by one. It perhaps could make a bird very dizzy.
Cheers!

 

I forgot to mention that my model had plastic torsion bars for hinges. I have no idea if they served any good purpose. The idea was to make the flop less violent, theoretically. Also, properly tuned it might provide a lower wind speed start up, and perhaps even some benefit in torque after the flop.
After I made the first post it came to mind to comment that whenever I watched the model in action, the image that it suggested to my mind was that of dutiful soldiers marching briskly around in a circle.

 

I see Birdies

Gilbert,
We probably came up with it about the same time but you have a lot better understanding of the math and had a much better model.
Just looking at 4 blades - if opposing blade tips were connected directly by a rod it could prevent the over swing and smooth it out so higher rpm could be reached?

We need some high tech help.

 

Hi guys,
Is this still applicable to my original query? Just the same, it has been a most intriguing conversation. It has me thinking.....(of which I am not equipped), is this not all the same as the Voith-Schneider system stated earlier? Fluid is fluid. No?

 

Find This

I'm glad you are OK with your high-jacked thread.

I just looked at the Voith-Schneider system.
How the heck did Voith Schneider ever figure that out.
They musta had better beer.

OK see if you can find me one of these.

I want a direct drive back yard wind turbine generator that charges fuel cells and pays for itself in 3 years.

 

http://www.renewabledevices.com/swift/photo1.htm

The fuel cells are the problem, not the wind generator. Your design has already been patented and unsuccessfully developed. Wind generators must be able to rapidly reorient themselves in strong, gusting wind, otherwise they tear themselves apart due to unbalanced centrifugal/gyroscopic forces. To understand the power of gyroscopic disturbance, hold a spinning bicycle wheel by its axle shafts and try to change the axis position suddenly. With your style of vertical axis windmill only part of the blade system is making power while the other side is out of balance. A large machine of that design would be extremely expensive compared to straight forward rotors and in high winds could self-destruct.

If a turbine goes slowly it won't have much torque unless it has a huge surface area. Much more materials makes it more expensive to build and engineer. If its gonna big big, I say make it real BIG. Here's the system I like!!
http://www.enviromission.com.au/project/video/video.htm