Windmill or Wind Turbine- powered boats: how many are out there, and are they viable?

"..An argument without facts is nonsense....Experimenting without measurement is fiddling..."

Just like computer programs, one is just dabbling and nowt else. They are not facts, just endless numbers of...er...well, more numbers without verification. Yet you seem to be very comfortable with them, especially when you lack the prerequisite knowledge to debate the subject, other than your pretty plots. You seem to use "numbers" spued from a program as your "facts" endlessly....ugh!

Windmaster
Rick is the expert at misdirection, diversion and evasion, to avoid answering real questions about the subject at hand. He doesn't like to be questioned nor answer direct questions. I and many other have tried in the past, but just get endless "endless fog" as nicely put by baeckmo:
http://www.boatdesign.net/forums/props/props-rake-28716-5.html

He is a dabbler but wishes to be taken seriously as a designer....well good for him, I'm all for everyone trying as much as the next guy. But, it requires and open objective mind and many years of real training and designing real boats and a professional attitude to the objective. He is one of the "show me your gallery" types, as means of justification,....ugh!

He even gives amateurs a bad name!...which is sad really. Because his knowledge on the practical aspects of what goes where with little model peddle boats and cycling gearing is very good. But he just can't help himself in an attempt to be the "saviour" and "I have a program that gives the answer"...sad really.

Tis fun to read the back and forth though...

 

Thanks for that.
One wonders what his aims are on this forum. He's unlikely to gain respect if he can't give any respect to others.

 

It will be up to folks like us....

I really see little reason for all the animosity, we all are dabblers in this particular area. The folks with real money are never going to look into this because it will demolish their entire system of fuel based propulsion. One thing we have all discovered here is that the air contains a fabulous amount of latent energy, and some arrangement of wings and levers will be able to extract it. All of us that have made models of various sizes have pretty much proven that there is a barrier that limits the Vmax of the entire system due to the generation of adverse thrust. No amount of refinement of the conventional approaches can circumvent this problem, except for tiny insignifcant gains. Yet we know that the force on a pylon (of a typical land based system) that holds a turbine is immense, and is actually driving the earth underneath it imperceptibly. Unfortunately, we are standing on the very same earth, so we notice nothing out of the ordinary. Since the earth weighs quadrillions of tons it would take millions of years to see any movement, but this doesn't mean that no work is being performed by the adverse thrust. Our job as tinkerers is to turn this thrust on it's head so it works for us. Just imagine the force on the bolts that hold these pylons down (looks to me like they use around 100 bolts, each 2 inches in diameter to do the job) so that must be a lot of wasted power. The thrust bearings are absolutely colossal in big turbines.

Another way to look at the problem is to use gravity as an example, as long as an object is in freefall it will accelerate (work is performed), but the moment it is on the ground all this work seems to stop. Obviously the work is still being performed, but it is invisible to us because of some misperception in the way we evaluate mechanical work.

My feeling is that we have all been sucked into the belief that getting energy out of the atmosphere is like getting something for nothing, or that you have to have wind first. This is a myth that needs to be done away with. Wind is nothing more than relative movement of a mass of air and another object or point of reference. In a wind tunnel the test object is absolutely stationary, and the air moves, neither the air nor foil really know who is actually moving.

As I have stated many times before on this thread, improving the efficiency of propellers or gearoxes will lead nowhere, because these already have been perfected and they don't do the job. As someone mentioned earlier, a turbine becomes a giant spinnaker at high RPM, with a huge swept area. When the spinnaker power equals the power developed at the water prop (or wheels as the case may be) there can be no further gains.

The approach I have outlined earlier has been met with strong resistance because everyone seems to look at ducts as some form of hinderance, and not as a closed system where all factors are under control. Energy passing through a closed system has to escape in some way, it cannot remain inside. Either it is returned to the environment unchanged, or it heats up the duct and radiates away as heat, or mechanical power is extracted. There are no other possibilities.

 

Michael
There are significant gains to be made with an electrical transmission with storage. The turbine needs to operate at its peak power point and the boat or car should be set at an economic speed. It does not have to vary speed as the wind waxes and wanes.

With an electrical generator on the turbine it is much easier to limit the peak power as well. It means the entire transmission does not have to be built to withstand the higher power the turbine can put out in strong wind.

I notice that Aeolus racers are allowed to use electric transmission and storage. I expect you will see some using this option as they look for better performance.

I am very pleased with the performance of my turbine. My next step is to set up a generator on it. I already have various electrical drives I can use for propulsion.

I will not do any testing for a while because I am taking one of my pedal boats on tour for a few weeks. When I get back it will be a bit warmer and I will give the turbi-prop boat one more spin and video it before I dismantle it and move onto the next phase with the electric system.

If you have not found the ventomobile blog it is worth a read. There are some interesting comments and you can pick up some useful detail on what they did:
http://www.clubofpioneers.com/projects/ventomobil/

Have you started building a duct yet?

Rick W

 

Windspeed

Rick
I have been looking again at your pdf speed graph on post #388.
Looks good. You reached 5 at one point but the average was more like 4.
I'm just wondering what the average wind strength was on that day and at that location?
If you didn't take any measurements yourself at that time, then maybe it is possible to look at weather records to find out?

 

bil
The average wind strength was about 2kph. If you look at the scale it shows the speed against distance. It is not against time. For much of the time I was at the lake it was close to dead calm. At times the lasers were just ghosting or even stopped.

My average speed for the entire time was maybe 1kph because I spent about three hours at the lake. There were two times I sat on the shore for long periods waiting for the wind. It was a day of light and flukey conditions. Virtually exact opposite of the other two times. I was lucky my son was able to get some reasonable video. He did not get the most consistent run because he was long gone. I was fortunate I had a few gusts while he was there. After he went there was one continuous run at about 4kph where the wind was quite steady. About one hour after I left the lake the wind strength increased.

As previously noted I needed about 10kph wind just to spin the turbine and 15 to 20kph to make good progress. The gearing limits me to about 30% of the apparent wind speed.

This variability gives a clue to why a system with storage would work well particularly in land-locked or coastal waters where the wind is often flukey or variable.

I want to give the mechanical system one more go just to see what I can get with it. I may even look for a slightly larger prop from my pile of them so I can get the best from the fixed gear mechanical system. South westerly winds are more consistent because they are a sea breeze so hopefully I can get those conditions for the next run.

Going down wind the turbine was acting as a brake in the light conditions. If I had a sail of equivalent area I would have got over 8kph. But without gearing I could not take advantage of it. With an electrical system I could have continued to get some power from the wind turbine and also use the water prop as a turbine or power it and get over 8kph.

An electrical system offers great flexibility compared with mechanical. Setting up smart controllers like Maximum Power Point Tracking can give at least 30% more power over a conventional electrical turbine. So there are significant benefits with an electrical turbine using MPPT over a simple mechanical system. The higher electrical losses are more than offset by the advantages.

Rick W.

 

Small Model direct into wind

Windmaster

You said you would publish details of your model boat.
Have you done it yet? I might like to make one if its simple to do, to see if your claims have any validity.

 

Bil

As a matter of fact I have put it up.
Its on: http://www.sailwings.net/windspinner.html
I hope you will make one.
I think everyone should make one incl. RW!
It's just a water prop and a wind-turbine on a common shaft. Simple really. But a real eye-opener on performance, but some would rather spend hours doing sums rather than perform a simple test.

 

My Aeolus Attempt

Greetings everyone...

Rick: You don't need to convince me of the generator-battery-controller-motor drive configuration, as this is the most logical way to build a vehicle in this day and age. Once you have electrical power going into a battery you can subject it to computer control, and can meter it out at with with infinite precision. The only problem I see is that some power will need to go directly to the motor as the charge rate of the system may exceed the generator/alternator output. In my current design (I have attached my latest drawing) I have opted for a multipole alternator arrangement that can cut out entire sections when the less power is required. The alternator design I am using is based on the Electrodyne truck alternator that has stationary armature and stator coils. The only moving part is the rotor.

The vehicle itself uses bicycle technologies. The motors are built into the wheels and are direct drive brushless DC hub-motors. These are very popular these days in Holland where there are millions of bicycles (and a lot of elderly folks with a lot of money that don't want to pedal that hard anymore), and they have reached a high level of development.

The fuselage is actually the duct itself, and is simply a fabric covering a thin framework. Most of the flow over the body is in undisturbed air so even a very thin membrane surface is sufficient. The turbine itself will be more robust and made out of fiberglass and metal plates. My drawing also shows the limits of the Aeolus rules, and how a duct with one square meter just barely fits. If you have the latest Adobe Reader you can zoom in to examine the details.

My main focus now is to find some sponsors and partners, because I think it will be more than I can manage alone.

 

Peter
What speed have you managed to record with this machine? Have you got a video clip of it progressing against some measurement so speed can be guaged.


Rick W

 

Michael
You need to determine a simple (low cost) means to demonstrate that you can get the power to drag ratio you need to make it more effective than a simple 2-bladed turbine. If you can do this then you may have something a sponsor is interested in supporting.

I also wonder about what happens when the breeze is from the side or from behind.

RicK W

 

I wish...

...I had a simple way to demonstrate this, but it seems just as much work to build a full-sized model as a scale model. It may even be more difficult to build a small model because of the initial complexity. As far as wind from behind or on the side, these are issues more for a boat, in which case there would be a pylon with the device on top and able to swivel into the relative wind. On a vehicle it is not really an issue, other than to have the ability to 'crab' into the wind. This car has 4 wheel steering that allows the body to find it's own alignment to the airstream. At a high rate of speed the relative wind can be accomodated (a gale might be too much of a good thing) by the action of the steering. Wind directly from behind is not useful as a startup condition obviously. However, I would point out, that this is not strictly a wind powered vehicle, but is powered by Latent Heat in the air, so all it needs is a power up cycle and a running start.

 

Michael
The latent heat is what I was saying earlier. Have you seen any cycle that shows this can be achieved? I can see how it will improve the pressure if it is achieved but I cannot find any reference that shows it is possible.

Rick W

 

Right before our eyes...

....How about a 20:1 L/D airfoil, where a 1 (one) pound pull (offsetting drag) produces a 20 pound force at right angles (lift). Where did the additional 19 pounds come from?

 

Michael
This is only force. It is not power. I can set up a lever and apply 1lb of force at one and get 100lb at the other end. Unless the foil travels in the direction of the lift there is no work being done.

A roller bearing can achieve a much high lift to drag ratio than a foil but this has nothing to do with work.

Rick W