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7 hours ago, RobG said:

I've said repeatedly that an electronic system can be better. I've even posted a conceptual design of a system that really would make a difference, so please stop saying that.

The system you proposed would replace the sailor/driver, and be absurdly complex to implement on a small lightweight boat. The system I (and I think Barfy) am talking about would augment the sailor/driver's ability to maintain steady flight, and as I've noted 500 times, be surprisingly simple to implement. ESC on cars does not require any form of 'look ahead' for example, and works extraordinarily well.

7 hours ago, RobG said:

The point you consistently ignore and apparently refuse to accept is that poor ride height control is not the reason wand–based foilers are hard to sail, nor is it significantly limiting performance (though of course for those at the very front of the fleet every 0.001% counts and for them, it may matter). Go watch someone trying to sail a Moth and you'll find they don't give up because of factors that an electronic ride height control system addresses.

We must be talking about different moths. Sure, at the pointy end of the fleet, the top guys are flying like fighter jets in formation (just like top race car drivers), but at what we used to call the 'vanguard' position, boats are showing no such flight stability. For sure there are improvements to be made for the average guy with a little electronic assist, and you are also delusional if you think poor ride height control doesn't limit performance - of course it does. Having said that, the Moth is probably the worst possible example of a small boat that could be improved with electronics, since it is such an intrinsically unstable platform which heavily taxes a whole other sailing skillset - imagine the possibilities with a cat, where you could implement managed take off, in flight stability and stability thru maneuvers.

8 hours ago, RobG said:

In regard to building a generally applicable ride height system, focusing exclusively on what the boat is doing (attitude, velocity, acceleration, etc. which is what a PID–based solution might use) is a red herring, the important part is working out what the wind and water are doing in front of the boat. Until you have a system that will do that, the gains from an electronic system are minimal, you're just tinkering at the margins.

Until the sea state (chop) is higher than the boat is out of the water, you can pretty much ignore it foiling - you're just talking about more or less foil mast immersion. So unless you are foiling in the open ocean with big rolling swells (which coincidentally we do every day here in the waters off Hawaii), it's not even an issue. And a smart PID could be programmed to differentiate between swell and boat motion relative to the local surface (ride height) in any case.

8 hours ago, RobG said:

The biggest gains are from anticipation of external factors, not reaction to boat movements or what's immediately under the hull.

Sometimes. And sometimes (often), the biggest gains come from simply going faster on a truer, more efficient course. It's very important to remember that a foiler is NOT constrained to the topography of the water surface, so reducing movement in the Z axis is similar to sailing a straighter course in terms of getting from A to B as quickly as possible.

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2 hours ago, surfsailor said:

The system you proposed would replace the sailor/driver, and be absurdly complex to implement on a small lightweight boat. The system I (and I think Barfy) am talking about would augment the sailor/driver's ability to maintain steady flight, and as I've noted 500 times, be surprisingly simple to implement. ESC on cars does not require any form of 'look ahead' for example, and works extraordinarily well.

ESC works in a 2 dimensional environment. We need something that works in a 3 dimensional environment, which is where the added complexity comes from. As an aside, if you want to use ESC as an example, you seem to dismiss the cost issues with the type of system you are proposing. While I accept that individual components are relatively cheap, they are also cheap for ESC, but the costs of even an ESC control box is anything but cheap. The same is true of an engine ECU which is way less complex than we need for foil control. The cost comes when you start building something of merchantable quality, that is robust enough for it's use and environment. For instance the simple matter of a small enough waterproof enclosure isn't cheap. As an individual you can use a plastic container with duck tape and plastic bags at almost no cost. for a commercial product, you need something a bit better. If a basic car engine ECU, which is little more than a processor with connectors, costs, say $1000, what would your system cost?

Quote

We must be talking about different moths. Sure, at the pointy end of the fleet, the top guys are flying like fighter jets in formation (just like top race car drivers), but at what we used to call the 'vanguard' position, boats are showing no such flight stability. For sure there are improvements to be made for the average guy with a little electronic assist, and you are also delusional if you think poor ride height control doesn't limit performance - of course it does. Having said that, the Moth is probably the worst possible example of a small boat that could be improved with electronics, since it is such an intrinsically unstable platform which heavily taxes a whole other sailing skillset - imagine the possibilities with a cat, where you could implement managed take off, in flight stability and stability thru maneuvers.

It's hard to know where to start because so much is wrong in this paragraph. To start with, an english lesson. The vanguard is the front, leading part of a group. I think you meant the rearguard ;) Then there is the issue of whether a Moth is the worst example of a small boat that could be improved. Once foiling, the platform stability is totally irrelevant. The platform is only relevant when it comes to pre take of and what happens when you "crash" off the foils. In flight, all foilers of a given configuration react in a very similar manner despite very different platforms, meaning that the Moth, UFO, Waszp and F101 have basically similar characteristics. It also comes as a surprise to most that the characteristics of a cat with wand controlled foils is rather similar to that of a monohull with Moth style foil configuration. I do accept there is one time where an electronic system would help, and that is in foiling tacks and gybes. You would need to be able to start a given sequence at the beginning of the manoeuvre and then learn to steer to that sequence, which is how the AC boys learnt to foil tack, and it would be an improvement on a reactive system, but it is something a reactive electronic system would not help with. 

Quote

Until the sea state (chop) is higher than the boat is out of the water, you can pretty much ignore it foiling - you're just talking about more or less foil mast immersion. So unless you are foiling in the open ocean with big rolling swells (which coincidentally we do every day here in the waters off Hawaii), it's not even an issue. And a smart PID could be programmed to differentiate between swell and boat motion relative to the local surface (ride height) in any case.

This really is where you show you don't understand. Let's start with the basics. The water movement within waves has a marked impact on foiling. This is why foilers behave so differently depending on whether you are going into the waves or with the waves. People assume that the boat stays level and the waves simply pass under the boat with the distance from the water changing. This is completely incorrect. If you were correct, a wand system would make the boat unsailable in waves. The heavier the boat, the less impact waves have, because inertia keeps the boat at a constant level, but on lightweight foilers, well, that's another matter. As an aside, foiling in big rolling swells is really easy. It's chopped up, confused seas with irregular patterns that is difficult.

The problem is not "more or less foil mast immersion" because there comes a point where if the foil gets too close to the surface, it will ventilate. It doesn't need to break the surface to do that. Also, you are ignoring the problems of leeway when going upwind with T foil boats. Another issue you seem to ignore is the lag between the flap moving and the amount of lift changing. People like to think it is instantaneous but at the speeds we are talking about, there is a lag. The slower the boat, the greater the lag. This is why we are seeing wands on Moths moving forward. That works to "anticipate" what the flap needs to do ahead of when the new amount of lift is needed so that when the boat gets to that point, the correct amount of lift is being produced. Don't think that this is a function of lag in the wand and system. It is not. It is a function of the fact that a change in flap does not lead to an instant change in the amount of lift. Without some anticipation in the system, the foils will not produce the correct amount of lift at the appropriate time and the boat becomes a bucking nightmare. Speeding up the movement of the flap, which can be done on a Moth through gearing, can make the matter worse because if you move the flap too fast, the flow stalls. The other thing to note is that the forward wand  used on Moths doesn't change its position because the boat goes up and down, but because the waves do. In waves, if the control system waits until the boat starts to move up and down, it would be too late.

It's seriously complex. I am not saying an electronic flight control system cannot be developed. I know it can. The issue is whether outside factors overpower the foils or whether the foils can be made to react to those outside influences. I think most, if not all who have sailed lightweight foilers know that those outside influences do overpower the foils and no system will change that because the limitation is in the ability of the foils, not in the systems. For instance, in a Moth, over 50% of the loads that push the boat down into the water that the foils need to overcome to fly are actually from the sail, not the weight of the boat and sailor. That is why sail trim has a greater impact on foiling than foil control.

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A Class

A very big part of you point is that foils get pushed outside of the lift that they can deliver.  You also seem to be very well aware of the opposite problem where foils do not stay deep enough.

I wholeheartedly agree that with speeds between "minimum needed for take-off" and lets say 120% of the minimum, exceeding maximum available lift has a high potential of occurring.  In this range of speeds, "foiling skill" is probably needed much more than any "potentially better" flap control scheme.

However, at higher speeds the "available lift" for what I would call a reasonable "starter / intermediate" foil, quickly starts getting to be big enough to not only support the weight of the boat, it gets big enough to accelerate the boat in the upward direction.  For this case, it becomes pretty hard for the sailor to cause more than momentary foil stall. 

Foils reaching the surface and/or ventilating are the bigger issue at medium and faster speeds.  If the sailor does something 'wrong' that leads to "excess" lift, a good control system on a "starter / intermediate" foil should be able drastically reduce events with the foil too close to the surface even at the expensive of a big speed loss with the high flap angles needed.

With existing systems, you make a point that a less experienced sailor does things that are the "wrong choice".  Again, there is not much help available at lower speeds.  However, at medium to higher speeds, speeds, the potential for an "improved" control system to prevent a "crash" goes up a bunch.  This does not directly translate into making a less experience sailor as fast as a better sailor.  However, preventing a portion of the crashes would translate in to a better chance that the newbie will stick with foiling until he/she gets better.   The higher the percentage for crash avoidance the higher the potential for not giving up on foiling.

 

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2 hours ago, A Class Sailor said:

ESC works in a 2 dimensional environment. We need something that works in a 3 dimensional environment, which is where the added complexity comes from. As an aside, if you want to use ESC as an example, you seem to dismiss the cost issues with the type of system you are proposing. While I accept that individual components are relatively cheap, they are also cheap for ESC, but the costs of even an ESC control box is anything but cheap. The same is true of an engine ECU which is way less complex than we need for foil control. The cost comes when you start building something of merchantable quality, that is robust enough for it's use and environment. For instance the simple matter of a small enough waterproof enclosure isn't cheap. As an individual you can use a plastic container with duck tape and plastic bags at almost no cost. for a commercial product, you need something a bit better. If a basic car engine ECU, which is little more than a processor with connectors, costs, say $1000, what would your system cost?

Cost excluding software is a few hundred to a grand USD. We're simply talking about creating a 'smart flap' on the main lifting foil - many orders of magnitude less complex than the ESC system on a car.

2 hours ago, A Class Sailor said:

It's hard to know where to start because so much is wrong in this paragraph. To start with, an english lesson. The vanguard is the front, leading part of a group. I think you meant the rearguard ;) Then there is the issue of whether a Moth is the worst example of a small boat that could be improved. Once foiling, the platform stability is totally irrelevant. The platform is only relevant when it comes to pre take of and what happens when you "crash" off the foils. In flight, all foilers of a given configuration react in a very similar manner despite very different platforms, meaning that the Moth, UFO, Waszp and F101 have basically similar characteristics. It also comes as a surprise to most that the characteristics of a cat with wand controlled foils is rather similar to that of a monohull with Moth style foil configuration. I do accept there is one time where an electronic system would help, and that is in foiling tacks and gybes. You would need to be able to start a given sequence at the beginning of the manoeuvre and then learn to steer to that sequence, which is how the AC boys learnt to foil tack, and it would be an improvement on a reactive system, but it is something a reactive electronic system would not help with. 

 

'Vanguard position' was was a running joke back in the day - hence the quotes. And the platform stability is very important for smooth take offs and recovery from touch downs, plus I was factoring the significant amounts of cant (windward heel) that the moths use in my assessment. And contrary to your assertion, a reactive system - which can process attitude data that is so small as to be undetectable to a human driver and make corrections in a few milliseconds - would be a huge asset to successfully executing foiling maneuvers, as well as a potentially great learning tool.

2 hours ago, A Class Sailor said:

This really is where you show you don't understand. Let's start with the basics. The water movement within waves has a marked impact on foiling. This is why foilers behave so differently depending on whether you are going into the waves or with the waves. People assume that the boat stays level and the waves simply pass under the boat with the distance from the water changing. This is completely incorrect. If you were correct, a wand system would make the boat unsailable in waves. The heavier the boat, the less impact waves have, because inertia keeps the boat at a constant level, but on lightweight foilers, well, that's another matter. As an aside, foiling in big rolling swells is really easy. It's chopped up, confused seas with irregular patterns that is difficult.

To be fair, L and Z foils which use the surface penetrating portion of the wing to mitigate leeway are sensitive to chop etc (since there needs to be an AoA greater than zero where it goes thru the surface) - but T foils do not, which is what we are talking about here. And you are also conveniently forgetting that the wand systems have play built into them specifically to mitigate the effect of small local surface texture (waves) on ride height. And yes, rolling swells are easy to foil in - you just foil up the hill, and then down the other side - but you are missing the point that an ESC 'assistant' would reference a gyro and/or GPS altitude for Z axis position, which would need to be factored in. 

2 hours ago, A Class Sailor said:

The problem is not "more or less foil mast immersion" because there comes a point where if the foil gets too close to the surface, it will ventilate. It doesn't need to break the surface to do that. Also, you are ignoring the problems of leeway when going upwind with T foil boats. Another issue you seem to ignore is the lag between the flap moving and the amount of lift changing. People like to think it is instantaneous but at the speeds we are talking about, there is a lag. The slower the boat, the greater the lag. This is why we are seeing wands on Moths moving forward. That works to "anticipate" what the flap needs to do ahead of when the new amount of lift is needed so that when the boat gets to that point, the correct amount of lift is being produced. Don't think that this is a function of lag in the wand and system. It is not. It is a function of the fact that a change in flap does not lead to an instant change in the amount of lift. Without some anticipation in the system, the foils will not produce the correct amount of lift at the appropriate time and the boat becomes a bucking nightmare. Speeding up the movement of the flap, which can be done on a Moth through gearing, can make the matter worse because if you move the flap too fast, the flow stalls. The other thing to note is that the forward wand  used on Moths doesn't change its position because the boat goes up and down, but because the waves do. In waves, if the control system waits until the boat starts to move up and down, it would be too late.

^ Holy crap that's a lot of misinformation.

1) Foils start losing lift at a distance of about half a chord length below the surface - the water surface actually deforms downward, and ultimately can lead to ventilation. If you need to maintain your ride height to avoid the chop, you can mitigate this by simply making the mast longer. Current kite foil masts are 115 cm, although much of that has to do with the extreme cant angles. The sweet spot for all but the highest performing windsurfers (in our fairly large short period chop) seems to be 70-80cm.

2) T-foils can combat leeway with cant, using the main lifting surface which is extremely efficient. That's how kites, moths, windsurfers, and the new AC75 to name a few do it.

3) What you perceive as 'lag' is actually a very late detection of the issue (don't forget the 'play' in the linkage), and then (usually), a massive over correction, further hampered by the relative slowness of the crude mechanical system used to actuate the flaps - and then a counter correction, ad nauseum. We are not talking compressible flow here. But we ARE talking 'bucking nightmare' - the very thing a system like the one I am proposing would solve. You can read up on PID's here: https://en.wikipedia.org/wiki/PID_controller

4) The best thing about moving the wand forward (increasing the distance between the sensor (wand) and Cl (main wing) on a moth is that - given the same 'play' to filter out water roughness -  the wand would be able to detect a smaller change in pitch. So it is a crude way of getting slightly closer to doing what a gyro could do exponentially better and quicker. In terms of response time, moving it forward 1 m on a boat going 20 kts would make the response time about 1/10th of a second faster.

2 hours ago, A Class Sailor said:

It's seriously complex. I am not saying an electronic flight control system cannot be developed. I know it can.

Actually, you've said that over and over. But let's just agree to disagree.

2 hours ago, A Class Sailor said:

The issue is whether outside factors overpower the foils or whether the foils can be made to react to those outside influences. I think most, if not all who have sailed lightweight foilers know that those outside influences do overpower the foils and no system will change that because the limitation is in the ability of the foils, not in the systems. For instance, in a Moth, over 50% of the loads that push the boat down into the water that the foils need to overcome to fly are actually from the sail, not the weight of the boat and sailor. That is why sail trim has a greater impact on foiling than foil control.

Outside factors can overpower any 'assist' type system. But that doesn't mean the assist system isn't a huge help. And you're wrong about the moth sail loading, at least upwind - the lift vector of a sail heeled to windward has a positive vertical (Z axis) component, which reduces the load on the lifting wing. But either way, it wouldn't matter - an electronic foil flap control system referencing a gyro would automatically correct for either situation.

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I'm wondering what would happen with independent control of the port and starboard flaps and an inverse V shaped foil like the one on the AC75 prototype?

Once healed to windward, the electronics would shift the height control from the wand onto the leeward foil, which I guess would increase righting moment, and then use the flap on the windward foil to control leeway. Potentially that would be quite a dumb system that would work with the same body movements described.

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8 hours ago, surfsailor said:

The system you proposed would replace the sailor/driver, and be absurdly complex to implement on a small lightweight boat.

No it wouldn't and yes it would. But that's what's required to make an appreciable difference to ease of use.

8 hours ago, surfsailor said:

We must be talking about different moths. Sure, at the pointy end of the fleet, the top guys are flying like fighter jets in formation (just like top race car drivers), but at what we used to call the 'vanguard' position, boats are showing no such flight stability. For sure there are improvements to be made for the average guy with a little electronic assist, and you are also delusional if you think poor ride height control doesn't limit performance - of course it does. Having said that, the Moth is probably the worst possible example of a small boat that could be improved with electronics, since it is such an intrinsically unstable platform which heavily taxes a whole other sailing skillset - imagine the possibilities with a cat, where you could implement managed take off, in flight stability and stability thru maneuvers.

Wands don't have "poor ride height control", they work very well. For those learning to sail Moths, ride height control is way, way down the list of issues. It's not an issue through manoeuvres, balance and agility are. Boats don't foil through tacks because the boat slows too much, not because the wand isn't doing its job. Similarly with gybes, it's about balance: electronic ride height control won't fix that.

Your biggest misconception is that you think wands are crap when they're actually pretty good, so you're over estimating the gains available. You might start by quantifying (not just speculating about) the shortcomings and determine the gains that are possible with an electronic system. Then you might have some basis for your claims rather then conjecture.

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1 hour ago, RobG said:

No it wouldn't and yes it would. But that's what's required to make an appreciable difference to ease of use.

Wands don't have "poor ride height control", they work very well. For those learning to sail Moths, ride height control is way, way down the list of issues. It's not an issue through manoeuvres, balance and agility are. Boats don't foil through tacks because the boat slows too much, not because the wand isn't doing its job. Similarly with gybes, it's about balance: electronic ride height control won't fix that.

Your biggest misconception is that you think wands are crap when they're actually pretty good, so you're over estimating the gains available. You might start by quantifying (not just speculating about) the shortcomings and determine the gains that are possible with an electronic system. Then you might have some basis for your claims rather then conjecture.

I'm not saying (and have not ever said) 'wands are crap'. They are a very clever mechanical design solution, especially the cams and so forth. I'm merely pointing out that there is more than one way to skin that cat, and suggesting that a gyro-based flap control system is potentially an entirely different ball game. The simplest way to unpack the potential advantages is to think of the inputs you would gain (over just referencing the water surface) from such a system: speed, pitch, roll, and  - most importantly - acceleration in each axis (X, Y and Z).

If your goal is to control the flap in the most optimum way, I can assure you that MORE input is a plus. And that the flap control system is obviously important or A) moths wouldn't have it, and B ) there would not be ongoing development. Not sure why this is so difficult to grasp, or why you and A-class continue to feel the need to put words in my mouth.  

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And although wands are a clever mechanical solution, just as my Aries vane steering is, all the boats that are going fast single hand use electronic auto pilot. Problem with the vane as I mentioned is only one input, wind direction,  and not able to apply bias. 

Mechanical solutions are robust, salt water impervious, but always single minded.

Not saying it would be an out of the box solution,but tuning parameters for different classes would be shared and tested. And would evolve in a way that that mechanical systems are not able to. This would cut costs and accelerate development.

With the moth for example,and I have always said I haven't sailed one, wouldn't coupled control of foil and rudder reacting in milli second corrections to achieve a stable pitch attitude at the edges of the foil's envelope due to speed and the other variables you have brought up make the pilot better able to concentrate on the myriad of other tasks necessary and result in a craft that is easier to sail?

Of course it may cost a bit, but perhaps negligible compared to the investment of the craft. And really comparing component costs of black box replacement such as an automotiVe ESC to a system that you buy new like an auto pilot is certainly a grey area. I paid 1/4 of the cost of a new Yamaha outboard for a matchbox sized module,I felt raped and specialized replacements are where these folk make their $$$ back.

And really an interesting discussion sure to inform anyone keen to scope the challenge of Developing such a system.

 

 

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3 hours ago, rgeek said:

I'm wondering what would happen with independent control of the port and starboard flaps and an inverse V shaped foil like the one on the AC75 prototype?

Once healed to windward, the electronics would shift the height control from the wand onto the leeward foil, which I guess would increase righting moment, and then use the flap on the windward foil to control leeway. Potentially that would be quite a dumb system that would work with the same body movements described.

One reason for the anhedral shape is to stop the upper foil "wing" from piercing the surface. I'm sure there's been lots of analysis on the perfect angle, which likely depends on your choice of wind, speed, sail area, and so on. More anhedral is more unstable, so there's also the ability of the systems to control the boat.

On a boat with precise control of cant, it can be used for gross control of the lift vector to provide suitable horizontal and vertical lift components. Fine control can be by independent flaps as you say. Using the flaps for RM induces some pretty big moments at the weakest part of the structure and the least effective place (right at the pivot point). The flaps can likely generate massive forces if they're designed to, but can the joint with the (one–design, supplied equipment) foil arm take it?

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2 hours ago, surfsailor said:

I'm not saying (and have not ever said) 'wands are crap'.

You wrote "you are also delusional if you think poor ride height control doesn't limit performance" (which I've never said or inferred), which, along with other things you've said, infer you don't have a high opinion of them. Sorry if my paraphrasing was too harsh.

The point is that you think there's a large gap between current wand systems and a simple electronic system that justifies the time, cost and effort to build one. So far, no one who's built an electronic system has found that to be so. Your challenge remains to identify the gap between current systems and an optimal system and show it's worth the effort.

To me it's a lot like the discussion on bowsprit mounted wands. Yes, they help, but they certainly aren't necessary and the improvement is marginal.

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No way.

It's the difference between an Aries wind vane and whatever they are using on the vendee globe.

 

 

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I am a foiling beginner (I have been for a while now) and my experience with the waszp is that better flap control would not make learning any easier. The effects of sheeting, steering and body movement are simply orders of magnitude greater than the wand/flap component of the control system.

To echo a point that was made up-thread, the reason it’s hard to learn to sail these boats is because you need to coordinate body, sheet hand and tiller hand constantly to keep everything in equilibrium. And you need to anticipate what’s about to change, because if you just react to it you’re already too late.

The control system is important, of course. But if your technique is right you can still get a poorly set-up boat to foil, whereas poor technique will stop you foiling even if Paul Goodison lent you his moth. I could describe dozens of different ways that I’ve lost control of the boat, but I'm pretty sure none of them were down to the slow response of the main foil flap.

For the beginner I could see a very small advantage to a high tech flap control system if it automatically set the ride height, so you didn’t have to fiddle with another bit of string while you tried to avoid crashing. But you’ll still have to learn the dexterity to do that, because the downhaul and outhaul won’t adjust themselves (not to mention all the other controls on a less simplified moth).

I can’t speak for potential performance gains for expert sailors (ask me again in ten years or so) but I really don't think that replacing the wand and mechanical linkage with sensors and computer processors would make the learning process any easier.

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If Chris Harris (of all people) can get more out of a Lotus (of all cars) with a Race mode that actually learns how to do more on a circuit as it goes around and around - then there is hope for electronic systems in foilers.

 

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4 hours ago, RobG said:

One reason for the anhedral shape is to stop the upper foil "wing" from piercing the surface. I'm sure there's been lots of analysis on the perfect angle, which likely depends on your choice of wind, speed, sail area, and so on. More anhedral is more unstable, so there's also the ability of the systems to control the boat.

On a boat with precise control of cant, it can be used for gross control of the lift vector to provide suitable horizontal and vertical lift components. Fine control can be by independent flaps as you say. Using the flaps for RM induces some pretty big moments at the weakest part of the structure and the least effective place (right at the pivot point). The flaps can likely generate massive forces if they're designed to, but can the joint with the (one–design, supplied equipment) foil arm take it?

There seems to be an interesting trend with all the latest foils to have a large flat section in the foil that are clearly intended for maximum performance at a specific heal angle. Gonnet has it, the latest iteration of 60s seem to have gone that direction, I think I saw the same on eh winter footage from one of the offshore multis as well (?)

A mechanical engineering challenge for sure, but given the weights being carried asymmetrically elsewhere I'd imagine not impossible. Not convinced by the argument for making small lightweight foilers easier, that it means eletronics are irrelevant? Maybe not. The power requirement challenge is very real though.

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10 hours ago, RobG said:

You wrote "you are also delusional if you think poor ride height control doesn't limit performance" (which I've never said or inferred), which, along with other things you've said, infer you don't have a high opinion of them. Sorry if my paraphrasing was too harsh.

The point is that you think there's a large gap between current wand systems and a simple electronic system that justifies the time, cost and effort to build one. So far, no one who's built an electronic system has found that to be so. Your challenge remains to identify the gap between current systems and an optimal system and show it's worth the effort.

To me it's a lot like the discussion on bowsprit mounted wands. Yes, they help, but they certainly aren't necessary and the improvement is marginal.

I was responding to the quote below. Let me put it another way - improving ride height control will improve performance at any level of foiling. If you believe the wand - a single input, reactive mechanical system - is the best possible flight control system, well good for you. But creating strawmen and quoting me out of context is not making your point.

To ME, this is a lot like the discussions I had with the yacht sail designers at my company in the early 90s about the validity of squaretop mainsail geometries for high performance monohulls. Guess how that one turned out?

On 10/24/2018 at 12:04 AM, RobG said:

The point you consistently ignore and apparently refuse to accept is that poor ride height control is not the reason wand–based foilers are hard to sail, nor is it significantly limiting performance (though of course for those at the very front of the fleet every 0.001% counts and for them, it may matter).

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8 hours ago, SeanPurdy said:

I am a foiling beginner (I have been for a while now) and my experience with the waszp is that better flap control would not make learning any easier. The effects of sheeting, steering and body movement are simply orders of magnitude greater than the wand/flap component of the control system.

 

To echo a point that was made up-thread, the reason it’s hard to learn to sail these boats is because you need to coordinate body, sheet hand and tiller hand constantly to keep everything in equilibrium. And you need to anticipate what’s about to change, because if you just react to it you’re already too late.

 

The control system is important, of course. But if your technique is right you can still get a poorly set-up boat to foil, whereas poor technique will stop you foiling even if Paul Goodison lent you his moth. I could describe dozens of different ways that I’ve lost control of the boat, but I'm pretty sure none of them were down to the slow response of the main foil flap.

 

For the beginner I could see a very small advantage to a high tech flap control system if it automatically set the ride height, so you didn’t have to fiddle with another bit of string while you tried to avoid crashing. But you’ll still have to learn the dexterity to do that, because the downhaul and outhaul won’t adjust themselves (not to mention all the other controls on a less simplified moth).

 

I can’t speak for potential performance gains for expert sailors (ask me again in ten years or so) but I really don't think that replacing the wand and mechanical linkage with sensors and computer processors would make the learning process any easier.

 

To be fair, an ESC system on a car isn't going to make it easier to learn how to drive a stickshift or merge on a freeway either. The point of the active flap would be to facilitate steadier flight (and perhaps managed take offs). It obviously could not control flight (without managing the entire system) - but would assist the pilot sailor in achieving fast, steady state flight. 

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47 minutes ago, Xlot said:

 

  ^ What happened to Adam May?

 

Remember when we thought we spotted him in Auckland at the twin-skin sailing demo?

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4 hours ago, Xlot said:

 

  ^ What happened to Adam May?

 

He took part in the British A-Cat Nationals this summer and ‘M’ay even have won it?

I guess the larger message behind that AR Technologies list of pre-AR designers is around how so many others of that Design Team have moved on to the new project, which must surely be backed by $B TT.  There will apparently be no AR Challenge this time despite what Matteo de Nora suggested in that recent interview in La Stampa about how ‘they never left’ when confronted with a question about the so-far dearth of Challengers and who may still enter.

But hey, that Sardian is still a possibility :D

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8 hours ago, rh2600 said:

Remember when we thought we spotted him in Auckland at the twin-skin sailing demo?

Lots of Artemis hoodies at the American magic test boat launch, they must of picked up a few of them 

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On 10/25/2018 at 9:20 PM, rgeek said:

Not convinced by the argument for making small lightweight foilers easier, that it means eletronics are irrelevant? Maybe not. The power requirement challenge is very real though.

Electronics (for ride height control) are irrelevant to the extent that they're not class legal in any current small foiler class. Ignoring that, there is certainly scope for an electronic wand replacement to do a better job. Issues confronting a would–be developer are the substantial investment of time and money to develop a suitable system for the marginal benefits available, plus the effort to get a class to adopt it. If a system was available for say $500 for a Moth that would run for 4 to 6 hours continuous use and had a useful fail–safe mode for when the battery dies, I think the class would seriously consider it.

Other startup and recently created classes could likely just add an appropriate section to the class rules if they want (as has been done to legalise wands).

I've seen power estimates that indicate a 12 volt 7Ah Gel rechargeable battery (less than $50) should be sufficient for a few hours of operation, but reality hasn't backed that up yet. I don't know what size the motivator needs to be, but the battery alone is 2 kg so maybe all up it's a 4 kg bulb on top of the strut with a sensor on the bow. The biggest power consumer is the flap motivator, which takes a lot more force than I ever expected, especially to get reasonable response times. It also consumes power just keeping the flap at a constant angle providing lift, so it's not a simple equation, some real life experimentation is required (absent the ability to do the job with computer modelling).

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Looks like $200 nz gets you a light weight electric bike lionbattery 36v, 12ah ip65 rated. That would go all day I reckon.

Worm gear servos are pretty good at holding position without using energy.

And yes, dev is expensive unless you have a group of motivated geeks. I reckon the firmware would be usable in many set ups once developed.

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4 hours ago, RobG said:

Electronics (for ride height control) are irrelevant to the extent that they're not class legal in any current small foiler class. Ignoring that, there is certainly scope for an electronic wand replacement to do a better job. Issues confronting a would–be developer are the substantial investment of time and money to develop a suitable system for the marginal benefits available, plus the effort to get a class to adopt it. If a system was available for say $500 for a Moth that would run for 4 to 6 hours continuous use and had a useful fail–safe mode for when the battery dies, I think the class would seriously consider it.

Other startup and recently created classes could likely just add an appropriate section to the class rules if they want (as has been done to legalise wands).

I've seen power estimates that indicate a 12 volt 7Ah Gel rechargeable battery (less than $50) should be sufficient for a few hours of operation, but reality hasn't backed that up yet. I don't know what size the motivator needs to be, but the battery alone is 2 kg so maybe all up it's a 4 kg bulb on top of the strut with a sensor on the bow. The biggest power consumer is the flap motivator, which takes a lot more force than I ever expected, especially to get reasonable response times. It also consumes power just keeping the flap at a constant angle providing lift, so it's not a simple equation, some real life experimentation is required (absent the ability to do the job with computer modelling).

No, can't see Jerry letting anything electronic near the F101 for instance. And given their Pro Vela experience that speaks volumes. The UFO is marketed as a beach toy. The WASPZ, keeping the running cost within the reach of mortals.

Wouldn't mess around with ultrasonic in the first instance. Just take the physical wand to a waterproof pot.

There's nothing off the shelf that would be usable as a battery. Some of the larger power tool batteries may be, but they're not waterproof. 2kg is heavy though. Lithium brings that down a lot.

Given the total lack of scale think more like $2-3,000 a unit or more. The electronic parts are a pretty small part of the equation.

Given a bit of bent carbon pipe, otherwise known as a boom, runs at $1,500, and I've heard of (unverified) silly numbers being paid for a single pair of spreaders, perhaps that's not too far-fetched.

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Having first hand experience of electronics plus salt water on small wet keelboats, nothing than wasn't a well-sealed and self-contained unit lasted very long. Personally I'd be unlikely to buy a small boat that needed electronics to function.

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3 hours ago, barfy said:

Looks like $200 nz gets you a light weight electric bike lionbattery 36v, 12ah ip65 rated. That would go all day I reckon.

Worm gear servos are pretty good at holding position without using energy.

And yes, dev is expensive unless you have a group of motivated geeks. I reckon the firmware would be usable in many set ups once developed.

Firmware would be pretty straightforward. This kind of niche application an open platform would work well as there would likely be a heavy reliance on GPL libraries for fusion and filtering.

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11 hours ago, barfy said:

Looks like $200 nz gets you a light weight electric bike lionbattery 36v, 12ah ip65 rated. That would go all day I reckon.

Worm gear servos are pretty good at holding position without using energy.

And yes, dev is expensive unless you have a group of motivated geeks. I reckon the firmware would be usable in many set ups once developed.

The software development would be absurdly easy, but it still won’t solve the issue A Class Sailor is trying to explain to you. 

I’ll use drones as an example since you keep bringing them up. From goofing around, I know my drone can lift a full beer can hung from the center of it’s body with no issue. Now if I start flying forward, still no issue. But once I start rapidly changing direction, that swinging mass will quickly overcome any hope of the PID loops being able to cope, and drone goes splat. 

The same applies to the mass of a sailor vs. the mass of a moth. 

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Bad example. I have flown many times with the battery dangling 5 inches off the bottom, two prop blades bent up at 90 degrees and finished two more laps and barely noticed it. Not all pid controllers are created alike. 

But do get that forces could easily combine to push the foil outside of it's flight envelope.  Having the controller actively adjusting pitch attitude using gyro input and rudder elevator might help to alleviate some weight shift mistakes. Having a stall alarm that it was beginning to make this adjustment might make it easier for a novice to learn better boat trim, before they crashed. My dad flew supersonic fighters seat of pants. 50 years later pilots input goes into a controller, that decides the best control surface movement within the envelope. 

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3 hours ago, barfy said:

Bad example. I have flown many times with the battery dangling 5 inches off the bottom, two prop blades bent up at 90 degrees and finished two more laps and barely noticed it. Not all pid controllers are created alike. 

But do get that forces could easily combine to push the foil outside of it's flight envelope.  Having the controller actively adjusting pitch attitude using gyro input and rudder elevator might help to alleviate some weight shift mistakes. Having a stall alarm that it was beginning to make this adjustment might make it easier for a novice to learn better boat trim, before they crashed. My dad flew supersonic fighters seat of pants. 50 years later pilots input goes into a controller, that decides the best control surface movement within the envelope. 

That’s nice and all, but you haven’t disproven what I said. Take your banged up drone and run a race course with a beer can hanging on a 1 meter string. We’ll talk afterwards. 

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Good challenge, I'll get back to you soon. Might have to fly over the gates tho as only one meter high.

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18 hours ago, rgeek said:

Given a bit of bent carbon pipe, otherwise known as a boom, runs at $1,500, and I've heard of (unverified) silly numbers being paid for a single pair of spreaders, perhaps that's not too far-fetched.

I think the boom price is fair, they're a bit more effort than a bent tube. The spreader cost is more an indication of what Mothies will pay for illusory fast bits, brand new BR spreaders are under AUD400 if you don't mind losing 0.0001kn 'cos they're 23.4g over weight. ;-)

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1 hour ago, RobG said:

 

 brand new BR spreaders are under AUD400 if you don't mind losing 0.0001kn 'cos they're 23.4g over weight. ;-)

1

:D

 

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