flutterby drive

[groverdamascus]

looking for some help with a new idea, an oscillating wind vane that drives an oscillating fish tail in the water. direct drive, one moving part! too good to be true, too simple to be new, I'm ready to begin the experiment but I'm thinking it's a good idea to research first (duh).
anyone ever seen such a thing?

[Guest625101138]

I do not believe it can be done with one moving part.

I expect that for any reasonable power level relative to the boat you will have nasty force couples to contend with.

For more meaningful assessment you would need to provide a sketch of what you have in mind.

Rick W.

[Kay9]

Some basic LAWS of physics start comming to mind real fast, that make me think this isnt likely to work.

Would like to see a drawing.

K9

[alan white]

looking for some help with a new idea, an oscillating wind vane that drives an oscillating fish tail in the water. direct drive, one moving part! too good to be true, too simple to be new, I'm ready to begin the experiment but I'm thinking it's a good idea to research first (duh).
anyone ever seen such a thing?

Yes, I know the concept. The upper (wind powered) part reciprocates by slinging a flag between two upright rods. The flag is longer (wider) than the distance between the rods. One of the rods is affixed to a pivot, which allows the other rod to rotate about the first rod 360 degrees.
The two rods are solidly connected together.
The whole assembly "waves" like a flag does, but with complete control, and the waving action causes the fixed rod to reciprocate. This in turn vertically connects to a semi-rigid fish-tail blade.
Orientation or indexing between the wind mill and the fish-tail is adjustable by a bevel gear pinion between two bevel ring gears. Allowing the pinion gear to rotate (by unlocking it) allows sailing at different points of sail.


Alan

[Tcubed]

Fascinating!

I have a sketch of this i drew in one of my sketch books of about twelve years ago. I had kind of forgotten about it and had no idea whether or not someone else had thought about it as well.

[alan white]

Fascinating!

I have a sketch of this i drew in one of my sketch books of about twelve years ago. I had kind of forgotten about it and had no idea whether or not someone else had thought about it as well.

I built a prototype and it worked quite well. The flag can also orient to pump up and down to run an irrigation pump through a lifting and dropping rod.

[ancient kayaker]

Don't see why it shouldn't work. I built a kite when I was a kid using an old model plane wing that oscillated side-to-side, just to annoy the older guys in the model plane club: it worked on both counts!

I can see the up and down direction of oscillation would work on all points of sailing but I don't see a horizontal one working too well except upwind. Maybe I'm not visualizing what you guys are describing. Let's see pictures!

[alan white]

I've never applied my windmill design to boat propulsion. The importsant thing is that it doessn't matter whether the fish-tail propulsion blade or the wind mill end are horizontal or vertical. However, a reciprocating wind mill on a horizontal axis is simpler. With a horizontal axis, a rod is made to go up and down. The rig above orients to the wind, but always goes up and down.
The connecting rod can be connected to a sliding ring that allows 360 degree rotation of the wind mill.
The relative orientation of the wind to the boat direction can easily self-index so the boat control would simply be a matter of steering and nothing else.
I don't have a scanner hooked up right now unfortuinately. I may try to hook one up tomorriow.

[Guest625101138]

I've never applied my windmill design to boat propulsion. The importsant thing is that it doessn't matter whether the fish-tail propulsion blade or the wind mill end are horizontal or vertical. However, a reciprocating wind mill on a horizontal axis is simpler. With a horizontal axis, a rod is made to go up and down. The rig above orients to the wind, but always goes up and down.
The connecting rod can be connected to a sliding ring that allows 360 degree rotation of the wind mill.
The relative orientation of the wind to the boat direction can easily self-index so the boat control would simply be a matter of steering and nothing else.
I don't have a scanner hooked up right now unfortuinately. I may try to hook one up tomorriow.

The original post stated ONE (1) moving part! This sounds like somewhat more. Still waiting to see a concept with one moving part.

Rick W

[alan white]

All I can imagine is a vertical axis windmill--- the kind with maybe four vanes. a vertical shaft down to prop in a tunnel drive that has a vertical turn in it, but the rpms would be way off without gearing.
I don't think it would make sense to limit the drive to one part except as an exercise resulting in a very very low efficiency.

[Tcubed]

Here are pictures of some sketches i made in 96. Excuse the terrible quality, almost all my stuff went underwater when one of my boats sank. I'll draw this out again so it's clearer soon.

Alan, i couldn't agree more. The first post described one moving part but i think that is quite unfeasible. A more realistic number is nearer half a dozen parts, which is still quite simple.

[alan white]

Hard to read those drawings, as you can imagine.
There are many methods by which a wind machine can propel a boat.
From a practical standpoint, the uses of any rotating or reciprocating system, no matter how many parts, will always be limited by the problem of large parts swinging or spinning around up there overhead.
Sails are limited to 3/4 of the compass in direction, but otherwise they are incredibly simple and trouble-free. They can be put in bags of all things, leaving little windage up otherwise.
Back to dreaming: The simplest system not using sails that I came up with was a horizontal axis pivot that hung a flag-like fabric area which caused an up and down pumping action. This was actually tested and worked well.
The up and down pumping caused a rod to go up and down exactly like an oil well. The application for marine propulsion might use a "whale-tail" part attached directly to the vertical rod.
The advantage is that the "sail", a rectangle of dacron, could be furled, leaving the frame alone just like a normal sailboat.
However, the drag component of such a rig would probably disqualify it from real use because of the difficulty in staying it----- and reefing presents even more problems.
I would like to understand what you've got there, but I can't understand the drawings. Not to complain--- haha--- I have NO drawings myself!

A.

[ancient kayaker]

The original post stated ONE (1) moving part! This sounds like somewhat more. Still waiting to see a concept with one moving part.

Rick W

Don't think it can be done if the objective is only one moving part. To get reciprocating motion from wind power needs two at least, the airfoil and a pivot attached to an arm with a pivot, not counting a mast to raise it to a useful hieght. At least the airfol could be rigidly attached to the hydrofoil qualifying as a single part. I am visualizing an arrangement similar to a very simple vane steering mechanism so the airfoil/hydrofoil can wave back and forth horizontally; vertical reciprocation would require more parts to link the airfoil and hydrofoil which could no longer be rigidly fastened together. Did Grover leave the building?

[Tcubed]

alan white's Avatar
alan white said<<<<<<<There are many methods by which a wind machine can propel a boat.
From a practical standpoint, the uses of any rotating or reciprocating system, no matter how many parts, will always be limited by the problem of large parts swinging or spinning around up there overhead.
Sails are limited to 3/4 of the compass in direction, but otherwise they are incredibly simple and trouble-free. They can be put in bags of all things, leaving little windage up otherwise.>>>>>>>

Exactly.
I guess what keeps us dreaming about these things is the notion of sailing at any point of sail and possibly even from within an enclosure just manipulating some levers and things. Kind of conjures up images of the mad inventor, doesn't it?..

[Tcubed]

Here is a bit better doodle i just drew of what i had in mind. This drawing is to illustrate nothing more than the basic aerodynamic part of the setup. The wing sail flaps back and forth within the 'yoke' which itself swings back and forth. The hole through which the sail goes is shaped such that the sail will automatically be angled and cambered at whatever it is designed for.

No doubt the least of all the problems would be a tremendous amount of noise. The cloth version i had thought of too but would no doubt be much less efficient. No doubt all these limitations passed through my mind and that is why there is only a couple of pages dedicated to this idea in my sketch books.

As a land based windmill system it is much more promising i think.

The inset diagram A is to show the yoke and the foil from above.

[alan white]

alan white's Avatar
alan white said<<<<<<<There are many methods by which a wind machine can propel a boat.
From a practical standpoint, the uses of any rotating or reciprocating system, no matter how many parts, will always be limited by the problem of large parts swinging or spinning around up there overhead.
Sails are limited to 3/4 of the compass in direction, but otherwise they are incredibly simple and trouble-free. They can be put in bags of all things, leaving little windage up otherwise.>>>>>>>

Exactly.
I guess what keeps us dreaming about these things is the notion of sailing at any point of sail and possibly even from within an enclosure just manipulating some levers and things. Kind of conjures up images of the mad inventor, doesn't it?..

I agree. What if you could sit inside in comfort in any weather and sail in any direction?
The windmill I designed and built was for irrigation in third world countries, but it reciprocates--- up and down or side to side. I wonder about its efficiency on a boat. It gets its drive from a percentage of its swept area--- theoretically, about 59 percent of the wind's power maximum.
Maybe I should try it out on a small boat. That would be interesting. The rig would always orient to the wind like a normal windmill. All I'd have to do would be to steer the boat. Add a tiller pilot self-steering and I could sit inside reading a book I suppose. The wind direction could shift 180 degrees and still I'd just continue towards my destination without adjusting a thing.

[clmanges]

That's pretty slick. I'm wondering now if you could extract some power from the excursion of the minor pivot axis. It wouldn't be much, maybe enough to run some little lights or something, but it might also serve as a dampening effect to reduce the noise. I'd approach this with a little electrical generator to bypass added mechanical complexity. No moving parts needed; mount a coil on the yoke and a magnet on the sail. The power wouldn't be steady, but a series of pulses, but it could feed a battery charger.

I might be off in my thinking, though; would dampening the sail take too much power away from the major pivot, or would it just slow it down some?

[alan white]

Of course you could extract electrical power using as Faraday coil. The power you get depends on a lot of factors having to do with stall characteristics, and how the charging controller is programmed. I'm no electronic expert though.

[Tcubed]

Damping the foil as it 'comes about' is quite interesting, necessary even. And of course extracting energy out of it makes it all the more interesting.

This subsystem can't be too greedy though as the foil needs to 'snap' through the dead angle quickly and smoothly. I guess ideally one would apply a powerful damping force in the final part of the transition, just before it comes to the stop. This would translate into brief but relatively intense bursts of electricity.

The ideal underwater propulsor for this would be a single oscillating foil. That way the cyclical forces are mirrored both above and underwater (as per the original idea) and if paired correctly, yaw torque effects could be minimized.

[alan white]

Remember, the foil underwater can be on a horizontal axis like a whale or dolphin's tail. I've seen bendy drive blades used on kayaks, but never up and down, which to me makes more sense because an individual stroke won't have much effect on boat wiggle if it works against the whole boat as a lever.

[Tcubed]

Up and down of course works just the same. The problem i see though, with up and down is how to keep the yokes (levers, actuator arms, whatever you want to call them) out of the water. With a vertical propulsor the yokes would be above water and the foil pierces the water surface, with a minimum of parasitic drag. Also there are no through-hulls.

[alan white]

But the up and down motion allows the windmill to re-orient automatically. A vertical axis type would have to be intelligently controlled. Or do you know how to make it self-reindexing? It's a lot like reindexing a wind vane self-steerer. What I'm talking about would only require helm steering, but not wind direction adjustments.

[Tcubed]

Indeed. I was not thinking about a self trimming system.

However, i think the nature of the oscillating force vectors upon the entire boat merit close analysis.
In the case of the horizontal setup the reaction on the boat would vary with the apparent wind angle; from pitching when up or downwind to a rolling effect when reaching. When it's vertical the yawing reactions should be able to be mostly eliminated. This could also be done with the horizontal setup but only for up/downwind. On a reach the foil would roll the boat with a corresponding loss of power (the force being partly wasted to roll the boat instead of going directly to the underwater foil).

There might even be a way of linking the vertical system such that it is self indexing but i can't think of it right now.

Another thing is that the yokes would need to be adjustable, such that the foil is allowed to rotate about the minor axis by greater or lesser degrees. This is directly equivalent to pitch adjustment in a propeller. The underwater foil should likewise have an adjustable amount of play to handle varying conditions.

This type of oscillating underwater foil has a remarkably high level of efficiency.

In a previous sketch i had drawn the angle of foil freedom being restrained by a line, which is a very simple and adjustable method.

[alan white]

When looking at the comparison between the vertical and horizontal axes, it was easy to see that the means of staying the vertical axis type was problematic; if it was to rotate 360 degrees, it would have to be free-standing except to just below the vane. The horizontal axis type brought the stays up to the halfway point of the vane--- a substantially higher point.
The flag type vane I came up with should also work very well on a horizontal axis at low wind speeds when gravity would distort the vertical axis vane.
Just like a flag, which at higher wind speeds follows a serpentine motion, but at low speeds sags and loses its nice serpentine motion.
I agree the vertical axis type underwater propulsion vane could be better, however. But it would take only a simple linkage mechanism to change up and down to side to side. so the upper wind vane could be horizaontal, converting to vertical for the hydraulic part.

[alan white]

There is a way for a vertical axis type to self index, by the way. If the upper part has a bevel gear (100 tooth) and the lower has one also (100 tooth), a bevelled pinion gear between (10 tooth) with a flywheel attached, horizontal shaft axis, each swing will cause the flywheel to absorb and store a little torque (but the flywheel has too much inertia to rotate very much, so by the time the vane has swung back, it's only lost a small fraction of its power, which is of course reclaimed by over-swinging the other side.
I designed this part so that a windmill could self-adjust to wind direction gradually without reacting to gusts.
Of course the horizaontal axis type solved the problem for good, eliminatinf the need for gears.

[aztek]

it could only work on a really light boat or WIG craft, mybe even a hybrid a katamaran with small wings and thin floatsat the end of them.

[alan white]

I would think a catamaran would work. It could go directly to windward. I would choose the horizontal axis type hooked directly to a bellcrank and a vertical axis propulsion vane. The wind vane could double as a stationary sail for downwind sailing in heavy wind.

[groverdamascus]

ok, I didnt mean one part exactly, but a solid system with no drive train. I know I still have steer the thing and like that.

[groverdamascus]

Yes, I know the concept. The upper (wind powered) part reciprocates by slinging a flag between two upright rods. The flag is longer (wider) than the distance between the rods. One of the rods is affixed to a pivot, which allows the other rod to rotate about the first rod 360 degrees.
The two rods are solidly connected together.
The whole assembly "waves" like a flag does, but with complete control, and the waving action causes the fixed rod to reciprocate. This in turn vertically connects to a semi-rigid fish-tail blade.
Orientation or indexing between the wind mill and the fish-tail is adjustable by a bevel gear pinion between two bevel ring gears. Allowing the pinion gear to rotate (by unlocking it) allows sailing at different points of sail.


Alan
thats very helpfull, I'm tickled pink by all the replys, sorry for the delay

[Guest625101138]

ok, I didnt mean one part exactly, but a solid system with no drive train. I know I still have steer the thing and like that.

It would help if you provide a sketch of what you are proposing. I expect it will end up a complex system and impart nasty oscillating forces into the boat.

Rick W

[groverdamascus]

I have a crude sketch, but I can't figure out to attach it here, this thing won't let me paste it. will work on drawing and wait for brain to figure how to post it.

[Guest625101138]

There are a few people who have difficulty attaching pictures. If you click on the paper clip icon when making a reply and nothing happens it is likely you have disabled pop-ups or some other security setting. It will not allow bitmap images. You will need to convert it to jpg or png if you have a bitmap. They are simply too wasteful on storage.

Rick W.