another idea

robherc,

Same here, however I never start to build a prototype unless the concept is clear in my head.

 

Wind Poker

In your opinion what is the percentage of chance for succeeding in doing a light 25/30 feet cat or tri windmill boat going against wind straight using mecanical transmission and the 2 air and water pitch controlled by a clever controller ?
Tri are perfect for the project
But cat could be with two mills
shutting or slowing down the downwind one to prevent pitchpole
Pitchpole would be easy to control with blade pitch

50%
100%
More ?


My opinion is... certain !

Others ? and reasons of doubt

 

well, to be honest, it'd probably be a 100% success, the question is: how fast could it go?

i'll warrant not very, myself. you'd be better off running on a tack with the wind to one side of the bow or the other. then you wouldn't be fighting a dead-on headwind and the drag from that.

i personally might go with just a cvt transmission and keep both turbine and prop fixed blade. many wind turbines are suited to a wide range of winds, and with the cvt transmission you could keep the screw turning at an optimal speed(or at least try to) for its shape.

much simpler and less work to keep in an ideal state.

 

It has already ben done with success and was not a particularly good design. There is a photo of a large cat in one of the threads.

Such a system will not beat sail in most conditions but it does allow you to go straight to windward.

Rick W

 

How do you know that?

You're so certain "it won't beat sail" - but how do you know? Anyway, what do you mean by "beat"? - vmg to windward?

 

By beat I mean faster around any triangular course.

The reason I know is that I have done the calculations. The system quickly runs into mechanical power limits. If you beef up the mechanicals to handle more power then you add more weight and you need more power and so it goes on.

Rick W

 

Dear Rick

There are other criteria for wind-powered boats apart from racing around triangles. Such as practicallity, the fastest boat around a triangle is usually not very user-friendly practical or even useful.

Sailors (have you ever sailed?) have been dreaming for centuries about being able sail directly into adverse winds. Now it can be done, you dismiss it as not very important. It doesn't matter that you may not be able to go as fast as on other points of sail. The fact that it can be done at all is an amazing fact that some even now find impossible to believe.

It may be true that a wind-turbine powered boat can't beat a racing sailboat around a triangle (although it's never been tried) - the sort of conventional sailboat that's fastest in those circumstances is pretty useless for cruising, exploring or getting easily from place to place.
A boat that can sail directly into the wind is pretty damn useful as most would admit.
You've done lots of "calculations" - that stuff about mechanical power limits is just simply plain wrong - there are things about this you have not taken into account or don't understand.
I have found that "calculations" - are not enough to get a reliable answer - you need to try things out practically. I have built two working wind-turbine boats myself (see videos on youtube) plus a number of models. So maybe I know something about this. Have you done any practical testing yourself?

 

I have seen your videos and they do not inspire me. I cover considerably more ground under my own power than you can with all that contraption and the best endeavors of the wind. I have learnt a little about efficient boat design and know a lot about the engineering of mechanical and electrical systems.

I doubt if you have ever handled a boat in heavy weather. If you had you would know the last thing you want to do is pound directly into the oncoming sea. Bear off a little and everything gets much easier. Somewhere around the pointing ability of a modern yacht is ideal.

A fast boat is a safe boat. Your boats are curiosities. They are not really practical as a means of covering any distance. They could be improved considerably with good propeller and turbine design but they still will not outperform a conventional sailing boat.

You could waste a lot of money trying to prove me wrong on this but nothing to stop you.

Rick W

 

Rick

I really think the power of the wind versus the power of your legs is no contest! I think anyone would think such a comparison ridiculous.
Can you go 24 hours a day and for weeks on end without rest? - of course you can't!
I certainly would not have called your boats "contraptions" before - but now you have introduced the term I really think your boats would qualify under the same heading.

Who said anything about heavy weather - you don't use your pedal boats in heavy weather do you?

If you know so much about turbine and propeller design why don't you prove it? Truth is - you've never made a wind-turbine boat, and, until you can provide evidence of your "superior knowledge" you can't really be taken seriously.

I challenge you to build one and prove that you are right! If you can do it and its better than mine then hats off to you!

Meanwhile,
You should really show politeness and respect for others achievements rather than claiming you know better, and trying to belittle others.

 

I have proven it. You simply do not understand. I cannot help your lack of understanding.

The idea has been around for a long time and there have been some fair efforts at making the most of it. None have been spectacular in their success.

I have the proof. Like I said you go ahead and build something that proves me wrong.

Rick W

 

frends, good to see so many with the same interests

 

Peter
Done and dusted. I have the data to prove it. Mine is faster than yours. And it was made with bits and pieces I had laying around. You have not bothered to acknowledge this. Instead you offer "proof" of a model pulling on a piece of string that your system is superior. You have your head in the sand. You have no scientific method whereby you actually measure performance. It is not good enough that it moves. It has to cover a certain distance in a certain time.

I will do one more test in favourable conditions to see what can be achieved and something for others to aim for. Then I will move on to electric to give a comparison.

Good luck with your fiddling.

Rick W

 

Well done!
Now perhaps you will be happy. You are the winner! (Is that what you wanted?)
However, you don't have data to prove anything. To compare one thing with another you need two sets of data not one. This is only your opinion.
I have achieved my object. I have goaded you into making your version and gained a lot of useful information in the process.
To claim such a great success, I can only say that you must have a very low expectation of into wind performance.
The average of less than 4kph is about half normal walking speed.
Personally, I'm not interested in winning or losing, only in finding out the truth.
Time will tell. These conversations a kept a long time.
....

 

Peter
Thank you for you gracious acknowledgment.

This was my first effort with a system I just threw together. It was far from optimal but it had no problem making good progress directly into the wind. It took me much longer to get around to test it than I anticipated. I will do one more test of this mechanical system. I believe I can get it to about 7kph directly into the wind in favourable conditions. If I had gearing and the right propeller I could get to maybe 60% of windspeed directly into the wind.

I will look forward to others taking on the challenge and proving what they can do. I am particularly interested in what Michael is doing as it might provide a new dimension.

Your system has some fundamental issues that will limit its performance but I look forward to some hard data from it. The variable pitch certainly has merit as would variable gearing as an alternative.

Overall I am even more convinced that electrical transmission, combined with electrical storage, offers by far and a away the most practical alternative to conventional sail.

This will be the path I follow.

Rick W

 

..Peter
Thank you for you gracious acknowledgment...

Wow, how humble and gracious, about as magnanimous as a kick in the face!

..You should really show politeness and respect for others achievements rather than claiming you know better,..

Ah, that requires acknowledgment of ones own limitations...and the respect for others. Wont get that. The desire and need to "be better" than others, just masks a deep rooted personality issue i fear. But as you say, which sums up pretty much most things in life:
..Personally, I'm not interested in winning or losing, only in finding out the truth...
Truth is far more important than my dick is bigger than yours..only those wishing to establish facts/truth understand this simple concept!!! Right and wrong is irrelevant....it is the "taking part"!