DDWFTTW - Directly Downwind Faster Than The Wind

Thousands upon thousands of people (most in fact) laugh outright at your above assertion that the key is to understand gearing. People who understand gearing COLD laugh at your assertion and say "it's got nothing to do with gearing, it's got a propeller".

You're problem Rick is that you assume that the explanation that YOU find simplest and best for YOU to explain is best for everyone -- simply not true.

No one has convinced more people nor educated more people on this topic than us (not even close). No one has been actively working on it longer than us (using your example you were many years behind) Everyone learns differently. I love the gearing example, I love the sails, the yoyo, the force * distance, on and on -- if someone laughs at one and turns it off, you have to approach it another way or you have no hope of being an educator.

Remember how you GAVE UP on the original thread and 'admitted' it was all a hoax? - I suggest that you not set yourself up as a shining example of one who has the one convincing key when the record of the forum shows otherwise. You've done some excellent work, but there simply is not 'one size fits all' when it comes to this brainteaser.

JB

 

For what it's worth, for experienced racing sailors, nothing (NOTHING) has been as repeatedly and instantly convincing as the following video (or related explanation). Casual sailors not so much as many of them simply won't believe that a boat (even ice-boats) can have a downwind VMG >WS.

http://www.youtube.com/watch?v=UGRFb8yNtBo

As a general rule, the 'gearing' videos and explanations are easily the most scoffed at by the average joe.

JB

 

I agree, but many people fail to grasp general principles and to apply them to other situations. They accept the reel but not the wind cart.

Some people just don't have any conceptual understanding. They need to have every single application of a principle explained.

Actually it works for some folks, who are trapped in the "feedback loop means perpetual motion" reasoning. Instead of thinking "what drives what?" they can see the airfoils as being pushed by the air against a kinematic constraint, and squeezed out with high velocity.

 

Wrong again. You mean to say that YOU became aware of the cart model a year later. I'm pretty sure Goodman built his physical cart to settle a running debate that stemmed from the brain teaser I had conceived of and posed much earlier still. The solution to the brain teaser was precisely the cart model you refer to. And then of course if you want to go back further, it turns out Bauer had actually built such a cart. But let's go back further still - it turns out he learned of it through a paper written by a student. Who knows how much further back it goes?

Being condescending and closed-minded doesn't fit well with getting your facts wrong.

 

Rick here are a few excerpts from PM's I've recieved warning me about engaging you.

Watching it unfold in front of my face is so much better than simply being warned of it via PM.

 

I assume, that many in the sailing community had this idea independently. John Perry described the puzzle in 2002 using this analogy:



Then later someone told him about Bauer:
http://www.btinternet.com/~sail/dwfttw02.htm

 

I think it's really cool how the internet has connected all these disconnected dots. Very different people at different times coming up with these ideas and none of them knowing about the first guy who built one.

I sure wish I could see the student paper that got Bauer and AMO started down their path. Perhaps he'll spot something about ddwfttw someday and step up and get the deserved credit (or explain how he/she got it from some other unknown source).

JB

 

Got to say here that the "gave up" was the real hoax and made for "peace keeping" purposes only. For that I give much credit for Rick. Some PM's were exchanged in the background..

 

Done as a joke, I'd give him credit. Otherwise I think it's shameful.

 

That is a question I think is worth another thread.. but giving up for someone's persistence even when you know he's wrong and you right doesn't change the truth in matter like this, especially when the subject will inevitably become proven later...

The difference how people comprehend this phenomen is even more amazing than the DDWFTTW itself..

 

DDWFTTW itself is moderately interesting. The number of technical questions and insights it presents is pretty impressive for such a simple device. But ultimately I agree that the sociological, psychological, and cognitive issues are far more interesting and surprising.

 

On the matter of the cart I am saying that I tried various methods to explain what was going on and this one was as unsuccessful as explaining the basic physics.

The most compelling and elegant explanation is the Youtube cotton reel analogy.

 

Do you understand the problem with making unsupported statements of an absolute nature? It's simply wrong to make such an assertion.

I think the cotton reel analogy is excellent. It's a better version of the yo-yo analogy I've offered for years. But that doesn't change the fact that it's COMPLETELY non-compelling to a lot of people.

You should also consider the difference between convincing someone in person vs. convincing them on the internet. It's two completely different worlds.

 

I should have added it is the most compelling I have seen and would be my preferred method to explain it and wished I had seen it much earlier.

You are right about the internet as even you are not immune to some of the spurious noise and have used it an unintelligent way simply in an attempt to discredit what I am stating. You should check sources before you repeat them but that would be professional and the internet supports all sorts of poor conduct.

The internet is a good place to make contact but if you want professional exchanges it is better to do it directly. Many of the contacts I make on the net lead to long-term contact and even meeting. Some have resulted in successful collaborations over a range of ideas and successful outcomes.

Rick W

 

And you should check your facts before deciding whether I've checked my sources, independently come to my own conclusions, or simply taken something at face value. But that wouldn't be the simple and absolute position to take in the face of a more complex situation. I understand the world is a pretty simple place that's just black and white for some people (and facts don't count).

Thanks for the keen tip. Of course that's how JB and I met over 15 years ago (on a hang gliding forum). We've since started a company together, built this goofy vehicle together, flown together, and worked together for many years. But you should definitely stick with the condescending approach. Always play to your strengths.

That's not an "addition". That's recanting an absolute position you recently put forth.