Sailors wrong for thousands of years?

I don't quite understand that part about exploiting the differences in disk torque to disk momentum. IMHO this mechanism exploits the velocity difference between the two media (true wind). As long this difference is not zero you can always produce net thrust (propeller_thrust - turbine_drag), if you are efficient enough.

What is "disk momentum"? The angular momentum of the rotor? I don't think that this is relevant here. The rotors could be massless and it would still work. It is simply a case of gearing.

 

I built a 9.6m dia windmill and mounted it on a 9m cat 25 years ago. It propelled the boat at 6 knots directly into 20 knots of breeze. I ran out of money towards the end so the 1m dia water prop was not very good (pushed as much water sideways as backwards) or it would have been quicker. Upwind vmg for the boat with conventional rig would have been lower than this.

The design top speed was 13 knots into 20 knots, at 180 rpm (slightly quicker tip speed ratio than Windmaster's!). The 6 was achieved at 110 rpm.

This was done on the cheap (wooden blades, commercial gears, recycled everything) and would not have made it across the channel on a rough day, much less an ocean. However, if it was built properly, there is no reason why it would not cross oceans. By the time a couple of thousand of them were built, they would be safer than a sail boat and more reliable.

As for using them on ships, this was very much the plan when I built mine, during the 80's oil price scare.

They were then, and remain, no less suitable for ships than sails, maybe more suitable as there is so little to do to operate them.

I mounted mine on a small mast stayed to a large stub mast, but on Mk2 I would mount the rig on a tripod (less interference) on a large diameter track, with the windmill on the downwind side for safety reasons, to allow the blades to cone which reduces a lot of bending stress and so it would automatically align with the wind.

Autogyroing is theoretically as effective upwind as a sloop and more so off the wind for the same swept area of sail. It is much more efficient than a sloop rig with the main blanketing the headsail on a broad reach. Lord Brabazon's autogyro beat the other Redwing's in the 1930's, but he had a bit of a drama when it piled into some moored boats and was asked to desist.

Gyroscopic effects were present, but not a problem. Would have been even less so with lighter blades.

Jim Wilkinson (Revelation 2) built his first windmill boat a couple of rivers north of me on the UK east coast. He was very helpful and keen to share knowledge. He went on to become the AYRS "expert" on windmill boats.

Both of us got the idea from an engineer in NZ (Jim Bates) who fitted one to a YW Diamond and achieved better performance than either of the cats. He built a second one for a cat with a 9.7m dia windmill (bit bigger than mine), which did not perform as well. Phil Weld (OSTAR winner) was involved with a day sailer version in the USA which I saw sailing, but have no information on.

As with unstayed rigs, if a small percentage of the money spent developing conventional sailboats was spent on windturbine boats, they would become a very viable proposition. If the Arab spring turns into the Arab winter, we may well see oil prices high enough to get ideas like this moving into the mainstream again.

All just my opinion, but to knock something because a bunch of amateurs tinkering on the river have not produced Blue Riband beaters shows a large lack of knowledge and/or imagination..

 

Rotary Sails

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Thanks very much for your post, Rob. I couldn't agree more!

 

As much of a rabid traditionalist as I am, these things are fascinating and I hope more time and effort are spent on development.

 

Thanks for your opinion Rob. I've been following your work ever since the early days when it was on "Tomorrow's World". Maybe even gave me some inspiration! I put a film of your boat (made for TV) in the files section of the Amateur Yacht Research Society group. You have mentioned a few times that your boat was a bit "scary" - well the low tipspeed ratio makes them less so. Pleased to see you still see the concept as worthwhile.

 

A Kiwi back in the early 70s, put a windmill on his mast, and hooked it up to a prop.He did five knots against a 15 knot headwind, directly to windward. Sea Spray magazine had an article on it.

 

Now that I have thought of it a bit, a wind turbine boat would have a few advantages.

1.) it is probably the only type of wind powered boat that can sail directly upwind,
2.) it needs very limited draft. Just enough to keep the prop from ventilating and for an adequate rudder, and
3.) It is probably the only wind powered boat type that can automatically 'reef'. Like a Jacobs wind turbine of the '30's, its blades can be mounted with springs and worming, so that greater RPM causes the blades to automatically feather. I read of one Jacobs that had been up for more than 30 years and went through two hurricanes and was still kicking out the watts.

That being said, I can see a few disadvantages.

1.) It would almost certainly be more expensive than a decent sailboat (which can not sail directly into the wind, but, under most circumstances, get there). The blades have to be carefully designed and balanced, a long drive shaft has to go up the mast and must be able to withstand some pretty high torque. To keep the weight down, I suspect some pretty expensive materials will have to be used,
2.) getting hit by a boom is bad, but nothing like being hit by a blade (this was Phil Bolger's major objection), and
3.) failure at sea could be uncommonly catastrophic. Imagine one blade flying loose from the hub. The other two could shake the structure to pieces. And even if it didn't, jury rigging could be quite difficult. And it's also a matter of luck where the loose blade goes. Being out on a rolling sea, with the boat pitching, yawing, and rolling, I believe could only heighten the chances of this happening. Such could put the blades through some interesting bending cycles.

I imagine such a machine would be most useful where straight sailboats fear to tread. Long winding narrow waterways where there is often no option but to go dead upwind. Such waters tend to be flatter than the open sea, so my third objection could be removed. The first could be justified by the need to go dead upwind and the second could be done away with by putting up a strong roof between the blades and the occupants, strong enough so a loose blade could not smash through.

I think, over long periods of time, snap rolls would be the worst enemy of this sort of set up. I suppose I would use either a dead rise hull or one with a narrow flat bottom and considerable flair to its sides. The gyroscopic effect of the blades could further dampen the roll, except when sailing dead upwind. Perhaps the hull development would need as much or more consideration than the machinery and blade design.

 

This seems a very fair appraisal however:

I would ask all to familiarise themselves with the work I have done on this already (http://www.sailwings.net/rotaryhome.html), and if they do, they will see that the kind of wind turbine I have been developing and testing is not the same as the one so often they see in their mind's eye as a kind of land-based turbine attached to the boat with blades whirling round at enormous speeds.
On the system I am developing and in fact, have done a lot of testing with, both in models and fullsize, the blades have a tipspeed ratio of 1.

That is to say the blades do not rotate ANY FASTER THAN THE WINDSPEED. This gives a number of advantages, one of which is that if (a remote possibility) some person should come into contact with the rotating blade the effect would in fact be no worse than being hit by a boom in an accidental gybe.

The possibility of "blades flying off" can easily be dealt with by a breakaway cord anyway.

It's a bit like saying "Don't fly because the wing might fall off the plane" - Yes, it might, and has (very rarely), but if its designed properly it won't.

 

First off, I commend you for the work you're doing. I checked out your site and noticed that instead of using a few rapidly rotating blades, you used quite a number of slower ones.

I can see how this could help a great deal on preventing blade breakage due to gyroscope effect combined with pitching and rolling.

As for the idea of a lanyard keeping a rapidly spinning blade under control, I find that idea a bit silly. Even if the lanyard holds, the broken blade would be free to be hit by one of the others, breaking pieces off it or one of the other blades.

As for the airplane analogy, there was a time when such advice was well founded. Airplanes did fall apart in the sky. It took about a generation or two to get the technology under some reasonable control. A lot of good airplanes were made in that period (say 1903-1943), but a lot of bad ones were too.
The '03 flyer was probably one of the worst. It had terrible pitch instability and was all but un flyable except for very short distances. I consider the '08 flyer to be the worlds first true airplane. As far as I know, it was the first one that was able to land where it took off from. Almost as bad as pitch instability was yaw instability (which seems to be very common during that period). With yaw instability, your plane could end up in a flat spin from which it would never recover and twirl like a pinwheel until it hit the ground at near highway speed.

My point is that the early successes were somewhat accidental and it took some time before this art of aircraft design became more of a science. There are plenty of dead test pilots to prove it.

What you have here is an untried technology that, thanks to you and other pioneers, has been proven at least feasible. Now it's time to push some boundaries. Have you ever had your boat out in rough weather (scaled to the size of the boat, of course)? Have you had it out in say four foot waves? Waves that would cause considerable pitching and rolling? And how long is the longest time you've had this craft out on the water? Have you ever taken it out on a beach camping cruise?

I would suggest you try the beach camping cruise. It would be a perfect test of it's reliability without facing scary conditions. At least you wouldn't have 'laboratory' conditions and you would be putting some wear on it.

I wouldn't at all be surprised if it if it completed such a voyage, say three days, then maybe three weeks, with no problems of any kind.

Looking at the video, it seemed to be moving at a reasonable clip. How fast does it go? And what is the diameter of the turbine?

 

Thanks for your comments

Yes, of course, there is need to do more testing. However, there is every indication that this is a useful and effective idea, there is much development to do which is a difficult process for an amateur without any support. As seen by the opinions of some on this forum, there is a lot of resistance to any idea which is "different" from normal. I can answer any questions about dimensions etc, through the contact form on the website.

 

What you need to do is find yourself an 'angel'. An angel being a person with considerable means to give you financial backing in exchange for a portion of the profits, should this idea become a money making venture.

At a writing, seminar, one of the speakers, who had recently published a crime novel and was describing how the genre worked, using bits and pieces of his life's story to illustrate his points, was asked about some missing time in his biography. He said he had a 'ten year sabbatical' (prison) and that the only way he could finish his novel was to get an 'angel' (investor) to back him. He found one and his book went on to become a successful Hollywood movie.

Start hanging with the alternative energy/green crowd. Somewhere in there you might find someone with money.

I wish you the best of luck.

 

Virtical axis turbine

I just had a thought.

What if the turbine had a vertical axis instead of a horizontal one.

It would eliminate a few headaches, but perhaps create a few new ones.

First off: let me explain my idea.

It is basically a 'Savonious' turbine where the blades are like horses on a merry go round. There would be four to eight of them and they would angled about 45 deg. from the chord line of the circle. They would be featherable to being parallel to that line for anchoring or survival conditions. The cylinder they form would be equal to the beam of the boat in diameter and maybe one to two times as tall. A single hulled craft would have two or more of them.

I would start with a catamaran with tall narrow hulls and a good deal of rocker in profile. The idea would be to get adequate displacement and reserve buoyancy with a rather small water plane area. This would be to prevent the pitching and rolling of the boat from fighting the gyroscopic effect of the turbine as much as possible.

Here are some of the pluses I see for such a system:

1.) The rotation axis always stays the same, vertical, so it always resists the pitching and rolling of the boat to the same degree, no matter which way the wind is coming from,

2.) It would only need one gear junction instead of two and that junction could be quite low in the craft. It could also be much simpler as it would not require either a hollow mast for the shaft to go through or a hollow shaft for the mast to go through, and

3.) if the structure came apart, due to over spinning, or structural failure, the blades would fly out away from the hull. Good for getting sued if there happens to be another boat near by, but, for the most part, harmless to those aboard this one.

Now for the minuses:

1.) The cylinder structure would almost certainly be heavier than the disc structure of a horizontal system, even if we include the weight of the mast the disc system must sit on top of. That is because the centrifugal force tends to pull the blades straight on the horizontal system, but bend them on the vertical one. Also, on the vertical system, the blades must be mounted on arms, one or two horizontal discs, or they must have a bowed shape to them, where the middle half of the bow is doing almost all the work,

2.) Only about half the blades on this cylinder would be doing any work. the other half would be being dragged upwind, where as all the blades on the disc would be pumping out power. (the theoretical area would be the height and the width of the cylinder, minus the drag of the blades being pulled upwind, and

3.) The blades on the cylinder would be harder to feather into the wind than the blades on the disc. The disc blades can feather themselves using centrifugal force, where the blades on the cylinder would need a more complicated system.

My guess is that if both the horizontal xis disc and the vertical cylinder systems both work, the cylinder system would be better off shore, where, perhaps, it would be better at dealing with seas and the more efficient disc system would be better inshore, where its greater efficiency would useful in bucking fast tides and river currents.

 

This is roughly what I was thinking of earlier when Windmaster said that he had built a single-axis wind-turbine boat. It turns out that I was mistaken, but I think it's an interesting idea. It looks like you are thinking of attaching a vertical-axis wind turbine to a conventional propeller. I would instead connect it to a vertical-axis propeller so that there would be no gears required.

There are various kinds of vertical-axis wind turbines. None of them are as efficient as the usual horizontal wind turbines in terms of the area of the wind intercepted, but they have some big advantages for use as a large power source on a boat. They are quieter, they stay in one place rather than swiveling around and they don't require as much support. Also, it may be that the gyroscopic effect of the vertical-axis turbine would offer useful pitch and roll resistance to a boat. I don't know if it would be significant, though.

Also, I would try a cycloturbine rather than a Savonius turbine. Cycloturbines are basically the turbine form of the cycloidal drive. You could, in principle switch back and forth between which was the turbine and which was the drive, depending on wind direction and which way you want to go. In particular, when going down wind it may be more efficient to use a wind cyclodial drive and a water cycloturbine. I'm just speculating here. I don't know of any actual numbers on this.

 

It's a very in accurate experiment that does not apply: scale both size and weight, wave action, wind shifts, top hamper and possibly many more factors that I am not thinking about. Could it work? yes but only under ideal conditions and mother nature is at most times far from ideal. Besides if it were pratical the Dutch would have made use of it Geo.

 

From reading the two articles you were kind enough to hot link for me, I can see the problems with the vertical turbine may be too difficult to over come. The chief among them, controlling the speed of the device. More than two blades might help this, but I'm skeptical. The multiple blades will certainly deal
The pulse torque issue (similar to how a multi cylinder engine does)

The cycloidial turbine idea is interesting, but I think it adds weight and complexity to the system. My vision is that the blades would be fixed in their angle of attack, except when they are feathered. More and more, I can visualize this whole contraption flying apart in gusting conditions.

Maybe it could make money on Youtube(r)