Windmaster
12-21-2009, 04:48 AM
As everybody knows :) A windmill powered boat can sail directly into the wind that powers it.
Recently, I put up a page on my website of a simple model to demonstrate direct-into-wind sailing,
This model has more drag behind the clr than in front and weathercocks automatically to windward.
Therefore, when released at the downwind end of a pond, it automatically sails directly to the upwind shore.
I'm hoping that publishing these plans will encourage others to make similar (but not necessarily exactly the same)
models.
If two or more of these models are released at the same time, the one that reaches the upwind bank first will have demonstrated the greatest efficiency of direct into wind sailing.
Many attempts have been made to predict mathematically the best setup for this kind of craft, but no matter how good the calculations, they mean nothing unless they can be proved by practical testing.
For example, one variable that cannot be accounted for, is the random variation of the natural wind all the time in both strength and direction.
There has been some dispute recently about what is the best setup for these models; whether it is better to use many windblades with a low tip speed ratio, turning at a low speed, or to use a few blades running much faster with a high tip-speed ratio.
These are the kinds of issues that could be resolved by this sort of comparative testing.
The only "rules" that would be required in a competition between different designers with different opinions about setup, would be that the swept area of the wind-rotor disc would be the same, therefore the same amount of potential power-producing wind would be intercepted for each case.
All other parameters would be optional.
Here in Norwich, UK, we are fortunate in having a purpose built model boating lake, free to use, which would be very suitable for this kind of testing (Eaton Park).
So I'm obviously interested to hear of anyone within reach that builds a model of this sort, so that comparative tests with my own model could be made.
Recently, I put up a page on my website of a simple model to demonstrate direct-into-wind sailing,
This model has more drag behind the clr than in front and weathercocks automatically to windward.
Therefore, when released at the downwind end of a pond, it automatically sails directly to the upwind shore.
I'm hoping that publishing these plans will encourage others to make similar (but not necessarily exactly the same)
models.
If two or more of these models are released at the same time, the one that reaches the upwind bank first will have demonstrated the greatest efficiency of direct into wind sailing.
Many attempts have been made to predict mathematically the best setup for this kind of craft, but no matter how good the calculations, they mean nothing unless they can be proved by practical testing.
For example, one variable that cannot be accounted for, is the random variation of the natural wind all the time in both strength and direction.
There has been some dispute recently about what is the best setup for these models; whether it is better to use many windblades with a low tip speed ratio, turning at a low speed, or to use a few blades running much faster with a high tip-speed ratio.
These are the kinds of issues that could be resolved by this sort of comparative testing.
The only "rules" that would be required in a competition between different designers with different opinions about setup, would be that the swept area of the wind-rotor disc would be the same, therefore the same amount of potential power-producing wind would be intercepted for each case.
All other parameters would be optional.
Here in Norwich, UK, we are fortunate in having a purpose built model boating lake, free to use, which would be very suitable for this kind of testing (Eaton Park).
So I'm obviously interested to hear of anyone within reach that builds a model of this sort, so that comparative tests with my own model could be made.