'Sailing'?? Directly to Windward

Thanks for your explanation, however you are missing my point, and you are still not considering the bigger picture. Of course it doesn't make any difference to the turbine itself whether it is on a fixed base or on a boat - that's obvious. But it does make a difference TO THE BOAT (sorry to shout). The object of this exercise is to make the boat progress against the wind, and if, in extracting maximum power from turbine you create a force that PREVENTS THE BOAT FROM GOING FORWARD it is counter-productive. Think about the autogiro once more - it is producing the lift which holds the aircraft up. This lift (turned through 90 degrees) is the force which stops the boat going forward. I really don't know any other way to put it.

Considering the efficiency of the rotor as you do is small beer compared to the massive lift force the boat has to overcome.

You seem a bit mixed up about the Solent Redwing. It worked like an autogiro with the rotor producing a lot of lift in the same way that a normal sail does, and this boat could do the same (broadly speaking) as a conventional sailboat. It could not sail directly against the wind and probably never could with the kind of (autogiro) rotor it had which was not designed to transmit power to an underwater prop, so that's nothing to do with the case here.

Yes, the blades on my models are probably not optimum, but work well enough for demonstration purposes.
I'm really looking for my theories to be proved wrong. Unfortunately, the only result is a lot of theory coming my way with no-one ever able to build anything which works anywhere remotely as well as my designs!

The object of publishing the plans of the "Windspinner" model was to encourage others to make them too. If, working from their theories, they were able to make one that progressed across a pond better than the original windspinner, then that would prove I was mistaken in my analysis (fine). But sadly I have not heard of anyone making one.
I am proposing a design competition between builders (if there were any) - models released together and the one reaching the upwind end of the pond first would obviously be the most efficient. That would reveal the true answer to this question.

 

I think the reason is more about 'packaging' dimensions. You can only fit so large turbine prop without having to raise the axis. Or Jeremy are you saying that even at same diameter fewer blades will provide less power?
I get that the efficiency in terms of drag/torque might be crappier but if we are talking just about the torque.

 

I'm not at all mixed up about anything in this thread, at least not yet.

The drag of your inefficient turbine will cause greater mast loads, and hence greater pitching and rolling moments, than a design with greater efficiency, a point I've tried to make repeatedly.

I also full understand the way the Redwing experiment worked and that it operated, in effect, like a conventional sail in terms of not being able to sail directly upwind.

There's nothing wrong with the way your boat works, as plenty of people have shown, wind turbine powered boats can be made to work (and they aren't really your theories, as others have already done much the same thing over the years). My only issue is that your own version isn't well optimised and with some work on the blades could, without doubt, have significantly better performance.

The issue of the practicality of any wind turbine powered small boat is a separate one and a topic that has been discussed here in depth before. The ability to go directly up wind is useful, but as others have found, it may be outweighed by the practical issues, particularly if operating in any sort of a blow. The main problem faced by wind turbine powered boats is the one of being able to reduce windage when needed. Feathering helps, but the more blades there are, and the broader their chord (and hence total thickness, assumign proper sections were used along the blade span) the greater the drag will be, acting fairly high up and providing an unwelcome force in a high wind.

 

Interested to hear about "the others". Let me know where I can see the videos or read the theories which I have expressed here. Thanks.
Actually, the layout of my boat was patented and I've seen no others since.

 

The power in a given area of wind at a given velocity is fixed, but only a part of it can be extracted. No matter how good a turbine design anyone comes up with, there is an upper limit to how much of that power can be extracted. The ultimate case is that for a theoretical machine that extracts all of the power in a given cross section of wind; the area behind it would have no flow, so where does all the air go that suddenly stops at the turbine? This is the basis for Betz Law (and I fully accept that some have problems accepting Betz theorem).

Generally, we can theoretically extract around 59% of the power available in any cross section of the wind, but few wind turbines manage to get more than around 40% of it. Multiblade, high solidity ratio, designs struggle to get better than about 25% of the available power. The very best, high aspect ratio, two or three blade units can get around 45% or a little more from the wind power available in a given cross section.

The simple answer is that a turbine with a smaller number of high aspect ratio blades will extract more power from a given cross section of wind over a broader range of wind speeds than will a multi blade turbine of the same diameter. The multiblade turbine may operate better at low wind speeds if the torque demand is high, but will very quickly start to lose out as the wind speed increases.

 

And by cross section you mean the circle drawn by blade tips? or the blade area cross section? (I am assuming the former)

 

Well, there is the 1976 article mentioned earlier in this thread, that is clearly prior art to your "invention" and therefore undermines your patent. There have also been boats built with wind turbines instead of sails, like this one in New Zealand:


The Windvinder boats are out around the world somewhere, sailing into the wind: http://www.windvinder.com/index.php?id=18&L=1

Or maybe Revelation II, seen here in the Channel Islands:



The idea you're claiming as your own has been used before, I'm afraid, so it isn't new or novel and shouldn't, at least in UK Patent Law, be patentable (if your agent has done a decent search for prior art).

 

Do you think I haven't seen these before? As I said there is no film of them working, and the builder of the Guernsey on is a recluse and tries to keep it a secret - in my opinion because it doesn't work well. The patent is granted in UK law. You still don't seem to understand that my design is different from these. I have explained it until I am blue in the face. I'm close to giving up since you don't seem to get it.
http://worldwide.espacenet.com/publ..._EP&FT=D&date=19950823&CC=GB&NR=2286570A&KC=A

 

wind-powered barge

I wonder if this idea of sailing to windward could be made more practical by changing the type of vessel from a sailboat to a barge. What about a huge ocean-going barge that is powered by a windmill instead of by a tugboat? If you are using a barge you must not care too much about speed, so the vagaries of the wind won't matter so much.

 

Sorry, yes, it's the area of the circle transcribed by the blade tips, not the blade area. The idea (in terms of getting best efficiency) is to maximise the area from which wind power is extracted and have the smallest area of blades commensurate with maintaining a reasonable level of blade loading (blade loading being the pressure ratio across the blade, which needs to be kept within reasonably close limits for good efficiency.

 

That's quite a good idea. They are more suited to pulling heavy weights rather than going fast. At least the barge would never get blown downwind. A valuable assist perhaps when the tugboat is dragging the barge to windward.

 

Well, I hate to say this, but are your patent claims defensible?

You claim that:

1) You have the rights to a horizontal axis, mast mounted, wind turbine connected to a means of propulsion, arranged so that the net torque reaction is zero. The same system is used in the New Zealand boat and in Revelation II, so this claim is either invalid or has been breached. If you haven't defended this claim, then it will be deemed, in law, that you no longer wish to make it.

2) You own the rights to the principle of the drive shaft. This claim was pre-dated by the prior art in the 1976 article and so is invalid.

3) and 4) You own the rights to a belt drive. This is a generic drive and so this claim is, in all probability, indefensible.

5) You own the rights to a mast positioned at the centre of lateral resistance of the boat. This claim is discredited by all other vessels that have ever had a mast positioned at the CLR and is similarly indefensible.

6) You own the rights to a counterbalanced turbine mount. There is, unfortunately, masses of prior art that shows that virtually all commercial wind turbines are similarly counterbalanced about the rotational mount.

7) You own the rights to a laterally extending blade mount, which may be defensible as a unique sub-claim.

8) You own the rights to the principle of a concentric drive down the mast. I doubt this, as concentric drive arrangements like this have been used for decades.

9) You own the rights to the particular configuration of belt and shaft drive you used. You don't, I'm afraid, I designed a hovercraft drive that was identical back in the 1970's and others have used similar shaft/belt configurations in the past.

10) You own the rights to variable pitch wind turbine blades. Obviously this is a fatuous claim, as there are hundreds of examples of variable pitch turbines, going right back to windmills with variable pitch blades made 100 years or more ago.

11) You own the rights to statically balanced variable pitch blades. I suggest you look at the hundreds of examples of blades with static balance in the variable pitch axis, including all those used on Hamilton Standard props since the 1940's.

12) You claim that any drive described forms a continuous drive. Not really novel, in my view.

13) You claim the rights to the turbine brake. There is plenty of prior art to show that turbine brakes have been in common use since the earliest days of the windmill, so this is not novel and is a fatuous claim.

14) You claim the rights to the torque reaction cancelling coaxial drive. This has been used on multiple applications, from contrarotating rotors, through torpedo drive systems, to the torque reaction elimination drive on the Gannet, so there is a lot of prior art that makes this claim worthless.

15) You claim the rights to a rotating mast turbine with a drive system for propulsion with variable pitch sails. There are other examples of this (as already quoted) so defend it you would need to establish who had prior art.

16) Appears to be substantially the same claim as 15), with the same caveat as to who had prior art.

17) No claim

18) You claim the rights to any vehicle or vessel incorporating a wind powered drive as described. There seem to be a significant number of similar "inventions" which may well show prior art, depending on the filing date, making this claim invalid.

19) You claim the right to the design of a vessel as described in the patent. Fair enough, but most of your claims are either not novel (and hence unpatentable, inasmuch as the patent cannot be defended) or are of limited value, in that they can be circumvented.

As someone else who have a couple of patents, I can suggest that you may have been poorly served by your patent agent or lawyer. He should have been aware of the prior art and advised against making claims that were indefensible. As your patent stands, I could pretty much make an exact copy of your patented design and there isn't anything you could legally do about it, as I'd be able to show prior art, pre-dating your 1995 filing date, for the majority of your claims, I'm afraid.

 

Are you a patent lawyer then? As well as an expert on almost everything else? I'm flattered you have spent so much time examining it. But it is granted. Look forward to seeing your copy. However, I doubt if you will make one since you spend all your time advising others and doing nothing yourself. I will not be discussing this further with you.
(P.S. - I have 4 patents - more than you! )

 

No, I am most certainly not a patent lawyer, I'm a retired scientist. As it happens I did work very closely with a patent lawyer, the one named on my own patents, and spent three years running the UK defence research programme, where I had to look at many hundreds of defence related patent ideas. Over the years I have learned a fair bit about patent law, including the core principle that the patent itself has no value, or legal standing, unless it can be defended. To be defended, the holder has to prove that they have the prior art, and that no one else has ever made public the idea that they are claiming as uniquely theirs before the date they filed their own claims.

Frankly I'm not the slightest bit impressed by any "mine's bigger than yours" point, as its the sort of comment that belongs in the playground.

I'm not minded to spend time and money on an interesting, but very limited, project. The practical issues surrounding the use of wind turbine powered small boats make the idea unattractive to me, even though they are an interesting experiment. As I mentioned before, I commend you for making an experimental boat to demonstrate to yourself that this well-known principle could be made to work; few are normally committed enough to take their ideas through to the proof-of-concept stage.

Will this principle ever be used practically? Maybe, for a limited range of craft. Although it isn't that well suited to a small boat, the physics of wind turbines means that the idea does scale reasonably well, such that the drawbacks that make this a fair weather only craft at small scale are less restrictive when it comes to much larger vessels. Larger vessels could almost certainly be best powered by a wind generator driving electric motor propulsion units, as the losses that make this a poor choice for a small boat would be overcome by the increased flexibility in terms of drive ratios and the ability to control propulsion when manoeuvring. The downside of such an approach is the restriction it places on deck space and the ability to load/unload the vessel, which may make it unattractive to commercial users.

 

High Tacker

Hello,

I'm a newcomer to this forum, and I should first thank Brian Eiland for his references to my boat (and the relevant website www.damsl.com), in this thread as well as in the thread about wishbone sailing rigs and A-frame masts. Also, Jeremy Harris has posted a photo of my boat just above here in this thread, in her first incarnation with a wind turbine rig.

I'm no newcomer to sailing directly to windward, with a wind turbine rig, straight into the eye of the wind, indeed started working at it in 1965. And I must take issue with Brian's initial post in this thread, in that he says that such is not "true" sailing, that it is "powering". Oh, but I insist that it IS true and proper sailing, just with a tad more mechanical sophistication than your standard sailboat powered by static sails. And I don't think this is just splitting hairs but is rather an important point that a wind turbine is not just some kind of wind-powered motor driving a propellor. Quite to the contrary, it is a sailing machine.

The conventional sailboat is itself, by definition, a machine, powered by the wind, albeit a much simpler machine than a wind turbine boat. Indeed, a conventional sailboat is one of the simplest of machines, has the mechanical advantage of a wedge, or a chisel, i.e., the advantage of an inclined plane in the water, created by the keel, a ramp inclined upwind, up which the boat is pushed by the force of the wind on the sail(s).

If you prefer to think of it as being pulled into low pressure on the leeward side of the sail, then suit yourself, but without the inclined plane created by the keel, the boat would be moved downwind and sideways, whether pushed or pulled, in any case would be moved in the direction of the resultant force of the wind on the sail(s), which is mostly sideways but also somewhat downwind. Nothing gets sucked upwind. There is no part of the force on the sail that is at all upwind. The essence of the sailboat is an airfoil pushing, or pulling...hey, let's say dragging...a hydrofoil up a ramp, complaining all the way, and a very stressful job it is.

Sailors simply FEEL that the process is not mechanical, that they are not riding on a machine, that it is somehow different, but that's just because, on a given point of sail, the boat has no moving parts, until the wind hits it, and then the whole thing moves. Nevertheless, it is a device that changes the direction of a force, and hence is a machine, by definition.

But a conventional sailboat has only that one simple advantage, whereas a wind-turbine-driven boat incorporates the mechanical advantages of levers, wheels, and axles, as well as wedges or inclined planes. Actually, it takes advantage of a much more sophisticated inclined plane, one that is twisted into a spiral, a helix. AHA! A screw! Instead of a 2-dimensional zigzag tacking track (the resultant of which is a straight line upwind), the wind turbine boat has a much narrower but 3-dimensional spiral track (the resultant of which is a straight line upwind). The high tack!

Instead of being static, the sails on a turbine are dynamic, rotating airfoils levering a wheel around and around, and that can then drive axles and then a propellor, which amounts to rotating hydrofoils. Hey, the only leverage in a conventional sailing rig is to the advantage of the wind, NOT to the boat or the sailor. That old conventional sail WANTS to rotate around the boat, and you fight it with dead weight, your body on the windward rail and/or lead in the keel, or with the buoyancy of an additional hull to leeward. On a wind turbine boat, you LET the sails get knocked over, and you get useful work out of that leverage.

Although I've gradually become convinced that there are more practical ways to harness wind power than a wind turbine mechanically driving a propellor on just the power available at the moment, I think that it's vastly important for sailors to realize and understand that such sailing directly to windward is possible. And it's important for sailors, not to mention designers, to understand that it's just an extension, an evolution of the same principles of mechanics, of physics, thermodynamics, aerodynamics and hydrodynamics, that are involved in simple sailing. Uh, since something is now revolving, dare I say REVolution? Just kidding...there will always be simple sailboats, and static sails are better on some points of sail, except for that upwind 90 degrees or so, about one quarter of where you want, and sooner or later will direly need, to go.

By the way, renowned New Zealand multihull designer Malcolm Tennant did the overall design of my boat, and Revolution was his idea for her name. I considered that to be somewhat hackneyed, hey, trite, but couldn't think of anything better at the time, so let him have his way. Later on, I nicknamed her, Her Hawtiness, hawt for horizontal axis wind turbine, and for her ability to take the high tack.

Her name is now Catbird Suite. She now has an A-frame mast and conventional sails, all on furlers. And I have plans for a somewhat smaller turbine for storing power and driving the boat electrically.

I've now read on this forum many attempts to explain the process of sailing directly upwind by means of a turbine, and yet so many, many more attempts to deny that it's possible, that I imagine a lot of doubters are still not convinced and many more sailors are not even aware of the possibility. So I've finally decided to throw in my two cents worth as one who has done it with small models, in 1965, who then in 1985 invested in New Zealander Jim Bates's second windmill boat (because he was way ahead of me) and accompanied Bates on long cruises around New Zealand in the late 80s, and then built a 63-ft. wind-turbine-driven catamaran for myself, largely based on Bates's research.

You can see a picture of Bates's first boat, Te Waka, on the thread, "Another idea..." on this forum. To my knowledge, his second boat, the catamaran, Tango, got the best results of any wind turbine boat so far, about 55% of the speed of the wind, straight into it, and a little better off the wind. There have been several others, including my own which you can read about at www.damsl.com I've attempted there to describe some thought experiments that I hope will enable visualization of how such a thing is entirely possible, and that it is indeed sailing.

I've also tried there to describe my reasoning as to why A-frames are better in some respects than single masts.

Cheers, Tom B.