Wing-drive

[kjell]

My WING-DRIVE is not made for racing. It is an alternative for safety sailing.

 

[CT 249]

Yes, but does that mean that the rig has to be mounted well above head level?

 

[kjell]

Yes, but does that mean that the rig has to be mounted well above head level?

The Wing-Drive is remote controlled from the cockpit there is no need to be on deck.You can se there are plenty of safety deck space.

 

[CT 249]

We seem to be going around in circles.....

In the left-hand drawing in your previous post, how do I paint or work on the deck without getting struck by the bottom of the rig as it spins around, if I am in my marina berth in a strong and fluky wind?

IF the rig is free to swing around on the boat in the left hand pic, no one can use some of the most valuable parts of the deck space (the bit in the middle of the boat) without potentially being hit by the rig as it swings around to follow the breeze.

In the right hand drawing, how does the proa come alongside a dock or raft up alongside another boat? Anything in the circle swept by the rig could be hit by the bottom of the rig.

What happens in the proa if I want to walk to the stern of the long hull to attend to a dock line, put on a fender, do some painting, whatever? The rig is free to swing around and hit me in the head.

These are NOT problems with a conventional rig because I can simply drop the sails and secure the boom in a fixed position. They are also not a problem with a conventional rig because the area swept by the boom is controlled by the amount of sheet that is let out.

Move the figure in the right-hand drawing to the left so that the figure is standing near the mast; perhaps to moor the boat, work on the mast bearing, whatever. What happens if the wind changes while he is doing this? Do you just hope that he can duck quickly?

 

[kjell]

Wing-Drive with spi.

 

[Kimba09]

its a matter of design of where wingsails can swing and the danger areas. About 8 yrs ago, made a 1/12 scale working , radio controlled model of a 42 Ft 4 wingsailed cat. The decks were all "safe areas" and the roof had 4 ft clearance for ppl to sit if they wished. To me converting conventional yachts is missing out some of the features. So the bimaran am now building will take advantage of the wingsail capabilities better. It too tho is an experiment, so there will be new info once we start testing.
It is really hard for ppl who haven't sailed with a wingsail rig to understand all their features. Kjell and I eve tho on other sides of the world have and am happy to say he has helped me. Hopefully can do the same for him too.
Still having had old sailors and boat builders on my boats there has been nothing but praise for these systems. the tracking ability of Kjells and my designs are incredible.

 

[Kimba09]

I have sailed and also left a small 16ft tri fend for itself on a dam in gale force winds for 3 days. the Wingsails feathered perfectly, no trouble at all. Also because a wingsail is very low drag, about 1/10th that of a round mast, let alone the rigging there is much less heeling from gusts at anchor. The "Soft wingsail option I think would have many areas to go wrong if trying to lower in a big wind. Putting Kjells or my rig into neutral is a finger task to change the control.

I see.

But they are extremely vulnerable to wave damage that way. And even though they reduce the capsizing moment quite a bit, they are still sticking up in the air.

Just that they are low aspect ratio now instead of high aspect ratio.

All that area can not be feathered except by pointing the bow into the wind.

IMHO, best to leave them up and find a way to make them self feather.

Another possible solution is a clever idea I saw in "WoodenBoat".

Basically the wing sails were really soft sails with the wing ribs acting internal battens. A very powerful halyard was needed to stretch the sail cloth tight.

Furling happened the usual way. The halyard was slacked and the sail cloth and ribs bunched up at the bottom.

 

[Kimba09]

If you like I can send you a copy of a video of my old tri, made about7 yrs ago, and it does take longer than a mnute to explain sailing, my email address is wingsails at yahoo.com

It only takes a minute or two to explain the basics of trim in a cloth sail, especially if you could use the wind indicator and marked mainsheet that Garry Hoyt created. It's a small proportion of the total knowledge needed to sail.

I'm still very unsure about the safety of the rig. I have looked at the pic you posted in this thread, at http://www.boatdesign.net/forums/attachments/sailboats/5653d1144178896-wing-drive-4603.jpg

It appears that;

* at no stage could anyone get onto the cabin top without lying down, or they will be in danger of getting hit by the rig which could swing around at any moment.

* there is a projection forward of the sail that sweeps across almost the full beam of the boat, therefore endangering anyone taller than the distance between the deck and the bottom of the rig. It also endangers anyTHING in that area; if you walk forward with a boathook it could be snagged by the rig. If you step backwards while tending to the anchor, you could be smashed by the fast-rotating forward projection of the rig. If you reached up to attend to the bimini, you would be within a few centimetres of being smashed in the fast by a piece of GRP or alloy, propelled by a tall rig. We rig windsurfers on the bows of our boats, and sometimes they get blown around a bit. That's no problem when they get blown into a fixed mast, it would be a major issue if they were struck by a swinging rig.

The danger seems even greater on your proposed twin-rig mono, where it would be utterly impossible to go forward and tend an anchor, step onto a dock, sunbake, varnish or do any other boatwork without the risk of being struck by a spinning rig, even at the dock.

It seems that all the dangers of a swinging boom are being projected over a larger area and (most importantly) that danger will be present at all times. We all know what happens if a mainsail (even a very rigid fully-battened one) is hoisted without the sheet being pulled on - it flogs back and forth and is a danger to those around.

I may be missing something, but if a version of your rig that has a 4m long base is sitting head to wind in a breeze coming from 0 degrees true at 4 metres per second, what happens when a sharp gust from 45 degrees true hits?

As far as I can judge, the following would occur;

1- the starboard-side leading edge would be struck by the new breeze. This would travel down the foil at an angle of attack of 45 degrees, causing the starboard wing to develop lift;

2- a fraction of a second later, the port-side leading edge would also be struck by the new breeze and develop lift;

3- after about four seconds, the new wind would strike the control tailplane. Only then will the tailplane start to have an effect and only then - after the rig has been developing power for four seconds - will it start to turn. I assume that the rig will take a second or two to overcome its inertia and turn, which will mean that it will be creating lift for another second or two.

4- inertia means that when the wing slows into the new position, head to wind at 45 degrees, there will be further forward motion imparted to the boat.

Therefore, the rig will have been producing lift for some 4 seconds - enough to move a boat forward at reasonable speed, more than enough to be a problem if trying to dock, sitting at anchor in a crowded bay, or sitting on dock lines.

I may be wrong about this, but surely there must be such effects in a wing rig? I have been using wing masts for some time and even stepping them you notice the buffeting effect of tiny windshifts; they certainly don't feel to have significantly less drag when being stepped when the boat is facing into the breeze.

Furthermore, as Ggguest pointed out, the effect of wind shear may be profound. In many conditions the apparent wind direction is around 10-20 degrees different between the bottom of the rig and the top of the rig - and that relationship changes dramatically as the boat moves over a large swell. If a rigid wing is in flow that is not uniform in its direction then it cannot be feathered directly into the wind over its entire span, can it?

 

[kjell]

I would like to have the opinión about wing sails by a person that have been sailing with one.
It seams that some think that the wings are rotating 360ª like a propeller, hitting everbody.

 

[Kimba09]

actually Kjell, have had 3 major hits with a boom but nothing yet from the wingsail. But then with the wing you just sit and steer , even the biplane rigged cat had both tails connected to the tiller, like an outboard motor control.

 

[kjell]

You and I know how easy and safe it is to navigate with wing sails. The only negative part is when going down winds (Running) The Wings are made to receive the wind from any other directions. To resolve this negative part, I designed a Spinnaker for the Wing-Drive.

 

[Kimba09]

Good idea Kijell, but i have found that the wingsail is no problem downwind, it can go whatever side you turn in from, and face it, absolutely nothing compares to how easy it is to gybe, I always say to my passengers "preparing to gybe , this can be tricky", they say ok let us know when and I have the joy to tell them its already happened, hahaha

 

[kjell]

My first RC Wing Sail Model. Based on Walker Wing sail design.

 

[kjell]

New WING-DRIVE.