The Wind Powered Sail-less Boat

I hope you're right. I'm tempted to think he could get a hold on this if he chose to. We've tried to engage him, but it seems impossible.

 

Rob
You need to go back to posts #111, #114 and #115 to see the hole that Guillermo dug for himself. He only accepted the idea of the blades working as a propeller when there was compelling visual evidence. I have an inkling pride is overriding reason here.

Rick W

 

I thought it worthwhile acknowledging Goodman's original efforts in providing a demonstration of his vehicle that caused me to think it through with science and logic:
http://www.ayrs.org/MOV05703.mpg

This is the original treadmill demo, long before the ones you see now on YouTube were produced. Notice the web site it is posted on.

Guillermo do you really think AYRS would deliberately set out to pull a hoax on simple minded people??????? Give it some thought. Are you prepared to discredit AYRS???

This is their charter along with some description of activities and member achievements:
"The AYRS is a UK registered Educational Charity (No 234081) dedicated to finding out how to make yachting better (faster, more fun, whatever you want it to be). Our members run from sober sided professional yacht designers and builders to bearded eccentrics full of ideas that they cannot make work. From our members have come the modern sailing multihulls, self-steering gear, sailboards, a flock of successful sailing hydrofoils, the World Speed Sailing Record system, etc etc. Now people are taking off with kiteboats and autogyro-sails, and the first amphibious bicycle!

Membership is open to anyone interested in the improvement of yachts and equipment through research and development."

Take a look at the Committee list:
http://www.ayrs.org/ayrsaddr.htm
Brave soul to say these respected folk would have any part in publishing a hoax to dupe the unsuspecting. You need to give more thought to things before you jump in and dig a hole so deep it is hard to back out.

Rick W

 

Jack Goodman is a great guy and a sharp engineer who I have the greatest respect for. But we do know that Andrew Bauer built a full-size (i.e. ridable) cart in the 1960's and built a working model that he put on a rotating turntable before any of us (including Goodman). Bauer used the turntable for the model because it let him experiment with the cart at steady state faster than the wind.

Bauer is no longer able to pursue his work, but I spoke to his wife and colleagues recently, and learned that he was not the first to concieve of this type of vehicle either. He read the idea in a student's paper and built his cart to settle a similar debate with A.M.O. Smith ( http://en.wikipedia.org/wiki/A.M.O._Smith ) back at Douglas Aircraft. Most likely we'll never know who was the first to conceive of this cart, but I suspect Bauer was the first to build a working model.

As an aside, his full scale cart had issues with the transmission "going unstable", and it seems unclear whether he decisively demonstrated DDWFTTW with that cart or not. We do know however that he demonstrated the model on the turntable for the folks at Aerovironment a few years ago, and they were quite impressed.

 

spork
I appreciate the historical context. I know Goodman never claimed to be the inventor but I believe his YouTube video was the catalyst that started the current interest.

On viewing that video I could not wrap my brain around it so I went searching for more information by Googling Goodman and dwfttw. I found the ARYS article and the treadmill video on AYRS. It was the treadmill that gave me the required insight to grasp it. Once seeing this the article made more sense.

I posted these snippets in this forum about 18 months ago but at that time it seems everyone reading the thread just accepted that it would work:
http://www.boatdesign.net/forums/boat-design/vertical-windmills-17546-3.html
Then again some do not actually read threads before diving in with an opinion.

The main point to come out of that discussion was Windmaster taking exception to my lax use of prop meaning anything with twisted foils whether it collects power or propels. I saw the error of my ways although it does get complex when the blades can change function simply through gearing.

Actually it would be very interesting to see original or at least earlier publications on the topic.

Interesting thing is that it has never been used for anything purposeful. It is just a curiosity.

Rick W.

 

Interestingly, Goodman's YouTube video appeared shortly before I posed the problem as a brainteaser on an R/C heli forum and a kitesurfing forum. That sparked far greater debate than I ever imagined it would. It was then that I learned about both Goodman's working model and Bauer's model. There's no question that Goodman's video caused quite a stir. Since that time, JB and I have been hell-bent on getting the Mythbusters to do a segment on this thing. As a result JB finally locked me in the lab at work until we built a working model as well. I think the most recent stir is surrounding the YouTube videos that we made naively thinking we would put the question to rest. Still the scepticism is almost unthinkable. Even professors of physics, aero, and mechanical engineering INSIST this is impossible.

I have couple of early Bauer articles as PDF's. If you PM me with an email I'll be happy to forward them. I would really love to get my hands on the paper that inspired the debate between Bauer and AMO Smith.

 

rickwill@bigpond.net.au

Or you could attach them here for all to read unless they have copyright.

Rick W

 

Well, they have Bauer's name on them, I think they're intended for public consumption. I'll give it a try.

 

And another...

 

It would have been interesting to discuss Bauer's work with him. He contemplates the faster than wind dead downwind but there is no analysis of it for the turbine/prop case. I wonder if they actually tried to achieve it with the model boat. I expect it would have been too small to go fast downwind. Wave drag would kill before the prop got into an effective regime.

Anyhow shows the science was well understood, demonstrated and reviewed almost 40 years ago. I guess we are just slow on the uptake or poorly informed. I thought I had discovered something novel when I tested my first upwind turbine boat in 1983. It did work but poorly. I have learnt a lot about prop design since then.

Actually it does highlight how silly Guillermo's position is when you read expert papers like this that were presented to professional groups so long ago.

Rick W

 

Rick, you've sparked some memories with your link back to the 'vertical windmills' thread. When I was a student at Liverpool University school of (terrestrial) architecture, one of my tutors, the late Peter Richardson, built and sailed a 'proof of concept' boat with a vertical axis turbine driving a water prop. This would have been 1984, I think. It had a two blade Darrieus 'giromill' H shaped turbine, (two blades chosen to be non self starting - a desirable property on a boat?) with each blade perhaps 1.5 metres long, moulded in grp in 3 parts to include the radial strut, then foam filled. I never witnessed the boat under way, but I understood it clearly worked, but there were issues with power control - it was pretty scarey. If there is interest, I may be able to contact some of his colleagues for further details.

 

I re-read Bauer's paper, Article 2, and figure 7 provides the areas of two propeller/turbine cases to achieve DDWFTTW. So he did do the analysis for this situation.

Rick W

 

By all accounts he was a very sharp guy. Unfortunately, he is now in a home for assisted living and no longer has the capacity to pursue these things. Some of his colleagues are still around and as sharp as can be. Unfortunately, A.M.O passed a few years ago.

 

It would have been useful to have access to these papers a few months ago. May have made some skeptics (not to mention names) take a bit more time to consider the possibility when you have an engineer with a doctorate in fluid dynamics, who works for Douglas Aircraft Company, preparing technical papers on the topic.

The size of the prop for his downwind vessel looks smaller than I have worked out but then one of his simplifications is to assume the whole propeller can be referred to the 70% radius. This point usually ends up being close to the point of maximum efficiency so his results could be optimistic. He also neglects transmission losses.

There must be some really thick or extremely arrogant people on the other sites you discuss the topic if they do not put any credence in this sort of technical discourse.

Rick W

 

Sorry about that. I never imagined for a moment that the sceptics I've encountered could possibly follow Bauer's work. I never meant to keep any of that hidden, it just never occured to me to post any of it. I would hope that well reasoned logic and analogies should do the trick. If not that, I can't imagine why people wouldn't take Drela's credentials as every bit as valid as Bauer's. But perhaps you're right. My record of convincing people hasn't been all that stellar.

You can't even begin to imagine. Much to my own embarrassment, the worst case that comes to mind is an instructor at my own alma mater (GA Tech).