Fixed Winged Cat

[fixed wing]

Cats with Wings – Moving beyond Fantasy and Drawing Boards

2009-01-20 Released

Are you one who likes to have the latest and greatest in fashion, gear and technology? Are your homes, offices and yachts spacious, sleek and smart? Do you like your privacy yet every once and a while what to throw open the doors and entertain?
Guess what? Harbor Wing Technologies, in collaboration with some of yachting’s most forward-thinking engineers, programmers and naval architects, is introducing one of the most stable, largest, greenest and user-friendly crafts afloat. Moving beyond the novel design and technology of the Maltese Falcon and its Falcon Rig of self-standing and rotating masts, Harbor Wing Technologies and Morrelli & Melvin are working on the plans for a range of WingSail® catamarans. All involved hope to see the 120 and 170-footers, currently on the drawing boards, by 2011. Equipped with Harbor Wing Technology’s Wing Sail, not only will they be large enough to host trade shows, they will be a showstoppers.
Spun from a way to efficiently and cost effectively patrol the Hawaiian National Marine Sanctuary, the collaboration’s solution can be applied to fleets of surveillance vessels, commercial delivery craft and the recreational market. The Wing Cat integrates breakthrough technologies in WingSail, hull, hydrofoil, data transmission, navigation and computer programming. A friendly user interface enables private yacht owners and crew to take advantage of technologies that otherwise would have been available only to the military. For the first time, a spacious, stable multihull with no rigging on deck, fewer crew, less crew fatigue and a whole lot more is available.
Just as on a powerboat, only one person is needed to take the helm, read instruments and steer a course on these winged cats. The computer programming takes the mystery out of trimming sails. No human interface is needed to constantly trim the sails. The WingSail’s computer’s load cells, anemometers and Internal Navigation Unit, “INU” inputs provide precise control and robotic responses that automatically depower the wing when wind velocity and sea conditions exceed the owner’s, captain’s and guests’ comfort levels, so if you don’t want to heel or fly a hull, you won’t. Additionally, Harbor Wing Technologies has developed a triple-redundant fully-maranized computer system similar to those used on commercial airliners of NASA space probes enabling the yacht’s systems to weather rouge waves and unexpected storm systems.
The ideal platform for the computer-controlled wing with tails that can be manually operated is a catamaran or a trimaran; providing stability, speed and space. The hulls, the salon and aft cockpit with its cabin top suitable for entertaining sightseers, sunbathers or really active guests, are spacious, regardless of where you are in the range. The plans for the hull of the 170-foot catamaran show two garages with workshop space and plenty of room to store 18-foot RIB’s; captain’s quarters with walk-in closets and en suite heads; crew lounges and cabins; laundry and six 200-square foot plus state rooms with private stairwells.
It comes as no surprise that this winged catamaran package is being considered by at least one group as a platform to host VIP and tradeshow events. “Whether at a dock or moving at 20-30 knots from port to port under wing power, this 170-foot winged catamaran packs pleasure, performance, utility and green technology into a vessel that can roam the ocean’s, moor off of St. Tropez or dock at Palm Island,” says Morrelli & Melvin’s Pete Melvin.
For more information on these developments, please visit www.HarborWingTech.com and www.MorrelliMelvin.com.

[jjtctaylor]

Whew,

HW and M&M will need buyers with really deep pockets. They make the 150- 170 ft craft and will certainly be show stoppers.

Doubt I could afford the entrance fee to look. But trickle down effect on successful launches should spur industry interest for scaled down versions and other cost effective solutions. Wish them success and hope their experiences and practical knowledge will take root for more affordable versions. All that plus higher credibility with survivability of the new technology.

JT

[Lodesman]

When you're selling a product, the devil is in the details. How do you inspire confidence in a "new-tech" product when you can't get the ads right. What the heck is a "rouge wave"? And all the boasting about contracts being made with the USN, doesn't explain why the warship on Harbor Wing's page is Canadian.

[fixed wing]

for all
Tom Speer emailed me witha lot of information that I would like to pass on with you about fixed wing sails on Cats and Tri`s
look at:
www.tspeer.com
http://www.tspeer.com/DesignTools/vortex95.xls


Here's a picture of the wing I helped design and build: http://www.tspeer.com/landyachts/Lydia/LydiaPhoto.pdf
OK, it's not on water, which simplifies things a lot. But it has been systematically investigated - see the wind tunnel report: http://www.tspeer.com/landyachts/Lydia/LydiaWT.pdf. And it taught us a lot about sailing rigid wings in general. We sailed it with positive control of the wing and no tail, experimented with canard control (not workable), and sailed it with different tail sizes and areas, with and without linking the flap and tail together.

Aside from any performance benefits, the key requirement for a rigid wing is that it be able to feather itself because the area cannot be reefed. The Harbor Wing concept has several advantages over the Walker Wingsail configuration in this regard. First and foremost is improved aerodynamic damping. The weather-vaning ability of a wingsail is proportional to its "tail volume" - the area of the tail times its distance from the pivot axis. You can have a large tail on a short arm, which is the Walker wingsail approach. Or you can have a small tail on a long arm, which was the LYDIA and Harbor Wing approach, and either can provide the same static stability for the wing. The difference is aerodynamic damping goes up by the square of the length of the tail. So the small-tail/long-arm approach provides much higher damping than the Walker wingsail. The Walker Wingsail would have had low damping and been subject to oscillations if it weren't augmented by active feedback control.

I've not run any numbers for the Harbor Wing configuration itself, but I have analyzed a similar configuration for another purpose, and to my eye the Harbor Wing configuration is consistent with having a damping ratio of approximately 0.4 to 0.6, and with a natural frequency on the order of a fifth to a half a hertz. This means that the wing will respond naturally within 2 - 3 seconds of a sudden gust, without oscillating back and forth afterward past one or two small overshoots. This means the wing can take care of itself if the control system fails, and the control system doesn't need to have a high duty cycle to keep the wing stabilized.

The Harbor Wing configuration shown is broken into an upper half and lower half, which gives it the ability to adjust to wind shear. This helps to reduce the moments that will result from a monolithic wing not being able to feather itself along the entire span simultaneously. This has performance and safety benefits.

The twin tails provide redundancy in the event of actuator failure, so the other surface will always be able to ensure the wing is at least feathered properly even for the case of a runaway actuator. And the twin tails can always be operating in their linear range, avoiding any deadband about zero angle of attack. This allows the wing to be precisely positioned at low (or zero) angle of attack, which is essential for avoiding uncontrolled forces and moments when at anchor or in a blow.

I think it's a practical configuration that builds on the experience of C Class catamaran wings and Harbor Wing's autonomous vehicle. Our experience with the LYDIA landyacht was the wing did a superb job of gust alleviation. Too good for racing, because when the gust hit it didn't get the "punch" of acceleration that is normally experienced with the onset of the gust. I think the Harbor Wing concept is more suited for cruisers than a large wingmast (say, >20% total area) and sail combination would be. Landyachts are routinely "moored" using dollies that allow them to swing freely to the wind and I've never seen one have a problem even when ovenight gusts exceeded 40 kt. The technique has become so successful for rigid wing landyachts that soft sail landyacht pilots have adopted it for their rigs, and don't even bother to drop the sails at night.

The LYDIA landyacht allowed the pilot to choose between three ways of controlling the wing while sailing. First was automatic control with tail and flap linked together, setting the tail angle to trim the wing and allowing it to track the apparent wind hands-off. Then there was manual control of the flap with aerodynamic control through the tail, which required more actions from the pilot when tacking. Finally, there was fully manual control, with the tail set at a fixed angle and the grabbing the boom to hold the wing in position.

Most pilots preferred fully manual control because it provided the best performance, due in large part to not responding to alleviate gusts. The workload was no higher than for a conventional soft sail, and the forces required to position the wing were low because of the aerodynamic balance provided by the tail.

The fully automatic aerodynamic control mode was ridiculously easy to sail. The pilot just sat there and steered. Automatic control provided better performace in very light winds because the tail was better at tracking shifty winds than was the pilot. The tail became the ultimate Windex. In all winds, one could trim the tail so the lee side trailoing edge telltales on the wing were on the verge of lifting, indicating stall. After sailing hands off for some time, with the wing shifting back and forth, applying a little pressure on the boom would result in the telltales flipping forward immediately. So the tail was doing an excellent job of keeping the wing at the set angle of attack.

I think the electronic control of the Harbor Wing is neat, but should be used as a convenience rather than a necessity.

Most cruisers are middle aged or older because it takes the better part of a lifetime to save up the money to buy the yacht. A rigid wing would cut way down on the workload required to sail the boat, especially in heavy conditions. There are no heavy sheet loads nor sails to hoist. It would improve safety by eliminating knockdowns.

The key question is motion of the boat and wing in a seaway, and I think that's a doable proposition. I'm hoping we'll see some sort of seakeeping analysis from Harbor Wing or M&M regarding the dynamics of the wing in a seaway.

[Mark424]

Originally Posted by Ilan gonen

Aussiesuede,
I wonder why are you trying to find a solution where there is no problem. Omer wing sail is designed such that it does not need these rudders. It rotates spontaneously into the wind. Isn't it better this way????
And yes, you are right, it is a simple design (it was relatively fast and easy to invent but very long and difficult to simplify), operates the same way as main sails but with excellent wing performance. What else is needed?

Ilan Gonen

Ilan,

Wonderful to have you aboard. I wonder if you have given any thought to not just the relative performance of the Omer Wing vs Bermuda Rig, but the additional performance/cost benefit of the whole system. E.g. the idea of a wing sail was originally brought to my attention by a cat designer who complained that one of the biggest detriments to a faster boat was weight and one of the big problems with weight is all the rig loads that you need to support (structural weight) - his claim was that a free standing mast (he was using a wing mast with sail) offered a good bang for the buck in reducing weight and improving performance. (I'll use a broad definition of performance, which could mean faster, more fuel efficient, or same speed with smaller easier to handle gear)

It also occurs to me looking at the force vector diagrams on your website that show the Omer Wing generates less healing force, so perhaps you could reduce weight of the keel as well.

On a mono, reducing the structural weight and keel probably won't help you on a retrofit, but on a fresh design, it could offset some of the cost and provide even more benefit. On a cat, you wouldn't save keel weight, but the structural weight savings is even more critical to performance.

Do you have numbers that would compare the weight of an Omer Wing to the rig it would replace? There is a lot of sail area, I wonder about the sail cloth weight required for wing vs traditional sail.

Is there such a thing as too little healing force? And could you trim in more healing - one of the nice things about a powered up sailboat is the stability of the motion - in contrast to a powerboat bobbing about about all axes.

The performance in very low winds (4-6 kn) is impressive. Were you forced to make any design tradeoffs for low wind performance? I'm thinking that a mono is for the most limited to hull speed, but on a cat you'd want a system that could routinely keep you in the 10-14 knot range for cruising (or faster in the right sea conditions). How would the design of your wing change for that application. (My apologies, it's been 25 years since my one and only fluid mechanics class and I forget all the theory) I seems that something designed for cat might need a thinner camber - or do I have that wrong.

Thanks again, keep up the good work! I for look forward to the day that the local club daysailers/racers have a wing, and the day that 40-50' cruising cats have wings. smaller - faster - cheaper? (that may come in time).

Mark

[Ilan gonen]

Mark,

Thanks for your post. It seems that you have given a lot of thoughts to the issue of wing sails, and I'll do my best to answer.

Weight:

A free standing mast reduces the structural weight since there is no downward compression of the stays (I recommend reading the very good article on free standing masts from Eric Sponberg in his web site: http://www.sponbergyachtdesign.com/StateoftheArt.htm).

Also, carbon fiber laminates are about half of the weight of aluminum, yet more than twice as strong. The free standing carbon mast of my boat (monohull, 37'), weighs about the same weight as the original stayed aluminum mast of the boat. However, since multihulls have high righting moment, the mast section size has to be bigger and wall thickness thicker which means heavier mast.

When installing a free standing wing sail, weight is also saved by eliminating the need for chain plates, keel weight, extra sails, furlers, stays and shrouds, number of winches and other deck gear.
The wing's sailcloth is a relatively light. Sail area required is about 85% of the standard boat. However, the wing is made of two main sails and one leading edge sail. In terms of sailcloth area, we have one extra main sail area. The extra sailcloth weight in my boat is about 30kg (17m high main sail).
As a result of so many weight variables, the total weight saving calculation is difficult to evaluate in general, and it should be calculated for a specific boat.

By saying:
"his claim was that a free standing mast (he was using a wing mast with sail) offered a good bang for the buck in reducing weight and improving performance. (I'll use a broad definition of performance, which could mean faster, more fuel efficient, or same speed with smaller easier to handle gear)"
You are absolutely right, but weight is obviously not the whole picture. A wing that generates more lift while inducing less drag, with no drag of stays (a big number), contributes much more to your broad definition of performance.

"Is there such a thing as too little healing force? And could you trim in more healing - one of the nice things about a powered up sailboat is the stability of the motion - in contrast to a powerboat bobbing about about all axes."
I don't think there is too little heeling force. Theoretically, when the wind is on the beam, and the wing rotates into the wind, all of the lift force generated by the wing, turns to be the driving force, while heeling force remains minimal and equal to drag only. In this case the boat will be at her max Speed.
If you want to stabilize the boat, you can increase the angle of attack by pulling the main sheet, and use the wing the same way you use a main sail as a stabilizer. You will, of course, get less lift/driving force.

"The performance in very low winds (4-6 kn) is impressive. Were you forced to make any design tradeoffs for low wind performance? I'm thinking that a mono is for the most limited to hull speed, but on a cat you'd want a system that could routinely keep you in the 10-14 knot range for cruising (or faster in the right sea conditions). How would the design of your wing change for that application? It seems that something designed for cat might need a thinner camber - or do I have that wrong."
One of my first design parameters was the question of how not to impose an aircraft wing onto a boat, but how to improve the existing gear of the sailing boat and make it have the "qualities" of a wing. It meant to use the same (as possible) mast, same boom, same sailcloth, same halyards system etc. This is why Omer wing sail has more sail area, lower aspect ratio and smaller L/D ratio than other hard wings. The other side of this equation is in being able to reef and fold the sails, in simplicity, in better cost/ performance, in better light wind performance, and in better downwind performance.

"Thanks again, keep up the good work! I for look forward to the day that the local club daysailers/racers have a wing, and the day that 40-50' cruising cats have wings. smaller - faster - cheaper? (that may come in time)."
I truly believe that wing sails (soft wings as well as hard ones) are the next step in the evolution of sails, and we will see a lot of them sailing (should we say winging) very soon.

Ilan

[fixed wing]

I found this today
Was done in 2008 and interview with Engadget
Can answer a lot of questions
Wait till engineering TV boots it up

Harbor Wing AUSV can sail into the sunset all by itself - Engadget

[fixed wing]

Take a look at Harbor Wings website they have added a sections on Frequently Asked QUESTIONS

this should answer most of the questions we all have had on Wing Sails

Harbor Wing Technologies - Autonomous Unmanned Surface Vessel - AUSV

Here are there Questions

What is new here? Hasn’t this been done before?
What happens when the boat is docked or moored in heavy wind?
How do you reef the WingSail?
What makes the WingSail turn?
What controls the WingSail angle of attack?
How do you trim the WingSail for varying top to bottom wind conditions?
There are no stays. How does the WingSail keep from breaking off in rough seas?
How well does the WingSail perform up and down wind?
How would you pilot a recreational catamaran with the WingSail system?
What happens if power or a computer fails?
Can WingSails be applied to Monohulls?
What other applications are there for the Harbor Wing system?

[Lodesman]

Hey Fixed Wing (or anyone else),

How does Aspect Ratio figure into the design of a wing-sail? Is a high aspect ratio desired? If so, why?

[jjtctaylor]

Generally less induced drag from aspect ratios greater than 4:1. AS always not the whole story as wing area counts more. It's a balance of area, foil shape, aspect ratio, tip shape/size against weight aloft, cost complication, and harmonic vibration (wing flutter). That's partly why not yet commercially available as standard options.

ONly with the advent of new materials, fabrication techniques does rigid wings now begin to have some expectation of success. It's not yet easy for the average shop to pull this together. In time there will be a standard set of engineering parameters where any boat builder (commercial or self-builder) can reapply and deliver a base set of performance expectations. Similar to today's options of rigs and sail area, rigid and semi-rigid wings will have a functional set of choices. Just takes more experience. Same as the development of the catamaran. Need a few more risk takers to get it mostly right !

[Lodesman]

Originally Posted by jjtctaylor

Generally less induced drag from aspect ratios greater than 4:1. AS always not the whole story as wing area counts more. It's a balance of area, foil shape, aspect ratio, tip shape/size against weight aloft

Yeah, OK, that's sort of what I'm getting at - but not really an answer. High aspect ratio foils have less induced drag for a given amount of lift generated, but they have greater form drag - and looking at the M&M design shown, with the twin controlerons top and bottom and there's a hockey-sock full of additional form drag. The tall, skinny sail puts weight higher up, and raises the centre of sail effort too for a greater tipping moment, so again I ask what's the advantage of the high-A/R sail over a low-A/R sail?

[jjtctaylor]

I don't think you will get an answer to your question. The two drags are square and inverse square of air speed. But the slope and point of origin differ due to effects like skin smoothness, foil shape etc. That can only be vetted by wind tunnel analysis of the final materials and shape. The optimum point in aircraft is evaluated against desired cruise speed. Whereas form/skin drag is highest at low speed and induced drag higher at higher speeds, then the designer must choose the best balance point.

There is VERY little research done at low speed wind velocities. No profit going slow. Thus this is a realm of unknown with the assumption that aircraft speeds can be scaled based on the Reynolds number. A lot of sailmakers continue to design under those assumptions. Not certain when foils have thickness the same general rules apply to low speed air.

I don't have any relation to M&M, but appears based on the design proposed that they desired to sail in medium to high wind velocities (for boats) The sail area to weight is too low. They want the clean air higher up and they want to create some twist by adjusting the AOA of the topmost section to avoid tip stall due to end vortex. Split design carries some added form loss, but based on their obvious intent a good trade.

Based on the boat mass, hard to flip it, unless sail area gets significantly higher which is also a good fit for their computer control. Less risk if it has functional issues. Looks like a high wind go-fast design. Not something I would use in lazy summers on the Chesapeake.

Thoughts ?

[fixed wing]

When I started the Blog last year many people said this was not going to work.

WELL look who is bringing back the Americas CUP and what did they sail a WING

so

Let’s look again at the Wing Vs the Cloth sail.

The same Designers who where behind the BMWO are the same designers that are behind the Harbor Wing project

If you want to argue with them about what a wing can do ok go ahead and if you do I think you will end up like the Swiss

Cheers for BMWO and the wing

Glad it is coming back home

[caribcat]

Amazing technology and great to see more challenging things discussed. I've always been intrigued by these but having been caught in an 'out of no-where storm' inshore North Atlantic (sunny to 85 knots in 20 minutes) I spent 4 hours running before it at 11 - 15 knots under bare poles only on a 70 foot cat, I'd be a little worried about these things in a storm. Also swing weight in a big sea must be a little of a concern, especially if you don't have daggerboards. Finally, in a slightly gust anchorage wouldn't the noise of it swinging be a little annoying? I assume that you can't leave it fixed for fear of sailing around on the anchor?

[fixed wing]

look at this maybe your questions will be answered

Fixed Wing Sail - Sailing Anarchy Forums