Moth on Foils: 35.9 knots(41.29 mph)

No, I do not think any one has considered it viable. Same reasons as Jon has said.

The rudder trim is like airplane elevator trim, nose down a bit to fly faster, nose up a bit to fly slower or maintain height with less power.

The wand is like the light system the Dambuster Bombers used, (Sorry if the US has never heard of this UK brilliance of WW2 bombing, you have to hire the old movie.) To fly at exactly the right height so that the bouncing bombs would sink just upstream of the Rhor dams, they has converging spotlights from each wing tip. The pilot had to fly the plane at exactly the height where the light beams converged.

He did not have to balance mainsheet and body against wind, steer around waves, look out for competitors (he did have to ignore German guns) and move body fore and aft for trim all at the same time, he had a couple of extra peple to help out. And not all of the planes survivived either.

Flying at a precise height is not easy in an airplane even with pilot input, and it is not easy in a boat. The wand operated main foil flap is the best system anyone has invented so far.

 

Wand vs manual

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Thanks , Tassie and Phil-I agree that the wand-first invented by Philip Hansford ,improved by Sam Bradfield and adapted by John Ilett to the Moth is the best yet.
I know that David Lugg used ext. tiller control of the rudder foil flap as his only means of altitude control on his 14. I tried twistgrip control of the mainfoil flap but don't have enough experience with it to make any judgement.The mechanics were quite simple and light,however.
David Luggs and Alan Smiths rationale on the 14, if I understand it correctly, was that control of the the rudder flap was like the elevator on an airplane. My rationale was/is that it seemed that if you were going to try to control the boat manually- using the main foil flap, as you do with a wand, was logical and had/has a chance of success. I'm a bit amazed that ,apparently, no one else has tried it.
It seems to me that if manual control was proved feasible -eliminating the weight and drag of the
wand as well as un-needed contol inputs in certain conditions- a small speed advantage might be gained. For instance,in certain wave conditions the manual control would allow the boat to "platform"-flying straight and level over waves rather than "contouring" as the wand would try to insist on.
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Luggs I14, though far from fully refined, flew with 100% manual control of the rudder flap-would manual control of the mainfoil flap work better?:
aus14_2.jpg

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I talked to Sam Bradfield about manual control of the Rave multifoiler and he thought it was pretty much impossible-that a human would not have fast enough reactions. On the Rave there are dual wands- one on each of two main foils. Their differential action provides RM in addition to lift. But not long after that a couple of guys in Gainesville rigged manual joysticks that 100% eliminated the wands. One of them told me that it was easy to sail that way-and fun as well. I think Sam was right- if the human was going to try to mimic the precise response of the wand(in certain conditions on a Rave it can feel like driving over a bumpy dirt road due to the wand response).
But the real world experience shows that manual control is possible on a Rave-probably because the human is NOT directly mimicing the wand response.

 

If foiling craft are going to be as popular as you think they are, Doug... wouldn't it be smart right now to develop the black box technology that would provide a generic ride control system with simplified and momentary manual override for specific circumstances?

All this kind of stuff has been around in racing cars for well over two decades now with known system issues, software types, weather proofing, the whole works. ABS, traction control, ride height, suspension bias... the whole tamale. Likewise, there should be a heads-up display, superimposed in the driver's sunglasses showing heading, wind speed and direction, flying height and any other pertinent info for the most efficient operation of the craft.

It would seem that these boats, which are supposed to be so technically superior, would have these sytems installed so that a discussion of this type would be moot.

This business of fiddling with manual twist grips, wave following wands and the like, is just so.... neanderthal, when you look at what is really out there for reasonable prices.

I'd think that an all-carbon boat with high tech, flying capabilities should be in that game and it should be incorporated as part of the whole system from the very beginning. Let's quit fooling around with yesterday's technology and get it on in the manner of a race car.

Chris

 

Techno nonsense?

Chris, in the class to which this thread is dedicated electronic altitude control is illegal as far as I know. And the wand is a brilliantly simple and effective way to accomplish the same thing. However, as the competition tightens in the Moth class I wouldn't be surprised to see manual control refined to an effective,fast system. And with my limited experience using mainfoil manual control to foil I think it has potential and it really is fun. But I can't say -yet- whether or not it could represent a speed increase vs a wand.
On larger multi and monofoilers electronic altitude control is a viable consideration and is being looked into. Heads-up display and all...

 

Doug, get real!

If you have ever sailed a modern Int. Moth at an all up weight of under 30kg in any sort of breeze ( which I know you have not), you might have some insight into how difficult this dinghy is to sail, and how quickly it responds to every wind variation; and with very signicant changes in heeling momentum and forward motion, not even to mention fore-aft attitude changes, and naturally ride height.
Therefore design your manual system of wand control, and give it to a couple of top world class Moth sailors to test, and we will all see how well they manage around the racing course.
This result should stop your nonsense of trying to develop a manual controlled main foil system for the Moth, and cut down on numerous postings on this area, which in reality, will go no-where
Regards, and take some advice for a change!
Sam

 

Moth on Foils

Frosh, I'm not trying to develop a manual system for a Moth. I have developed a system for a larger boat that works.
Manual systems- as I mentioned before- have worked on the Rave and on the first I14 foiler. I'd bet it would work on the Moth-and reduce drag- but be somewhat difficult to learn well.

 

I'd bet it would work on the Moth-and reduce drag- but be somewhat difficult to learn well. QUOTE- Doug Lord

In my part of the world this is termed "Unreasonable obsession" and "Being in denial".

 

Doug,
The K.I.S.S. method works best.
Remember, we only have two (2) hands. one on the tiller and one one the Mainsheet. both are under constant adjustment.
I like knowing the centre foil is indepentent in its adjustment. I think manual would be a nightmare in big water.

 

Moth on Foils

You're right ,of course, Grant but there is nothing I can think of that is mechanically simpler, with less weight and less drag than a manual mainflap control. It will take someone willing to try it-learning it well-to determine whether or not it is faster in the Moth class. It will not be easier but it might give a slight edge in speed. People learning to fly helicopters proved a long time ago that 'multitasking' of several parameters at one time is possible-just takes practice-and a good system.
I imagine somebody might give it a try as things eventually tighten up in the class.But it will take somebody willing(and hungry enough) to give some real time and effort to learning how to make it work.

 

Didn't you just say that there were serious issues and then used the Rave to illustrate those? Electronic control systems sample variables at astounding rates and apply those changes instantaneously. As in, speed of light, types of instantaneously. What's a faster way to manage the system than that?

Ultimately, for the fastest boat possible in this performance environment, it will be necessary to install a fly-by-wire system. Once integrated, there won't be a human capable of beating it.

Great, can't wait to see it (them) fly.

As for the class not adopting the fly-by-wire system... this one is really simple. One only has to make a foiling Moth some 10% bigger in all dimensions, install the fly by wire system, price it as a loss leader at, or below, that of the existing boats, show that it can smoke any human driven Moth out there and the class is dead in the water because of no additional sales of the existing design. When the sales drop to dust, the manufacturers will start building the teensy bit bigger Moth with electronics, the class will adopt new rules to reflect the interests of the builders and buyers and the game is set until the next iteration of technology hits the street.

And as a last note, here I was under the impression that you were all about the latest tech in the name of speed and coolness. That affordable, manual systems were so passe for you in your search for all things groovy and foiley. Now you show that you're just a bone simple dude who got himself off track for all these months in the heady world of carbonification.

Very funny stuff, Doug.

 

I suppose the first foil would adjust heave quicker than the rear foil?

It might be nice if you could get some feedback from the foil, maybe to your foot?

 

It's actually a requirement for stable pitch-heave coupling that the forward foil react faster to heave than the aft foil. The forward foil should control heave and the aft foil should control the pitch attitude.

One point that's been missed in the discussion about manual control is the desirability of controlling pitch trim. On the Moth, this is done by moving crew weight forward and aft. The problem with controlling the center of gravity is it changes stability as well as trim.

It would be helpful to have a flap on the aft foil that could be used to adjust the pitch trim. This would not have to be actively controlled. It would be used to fine tune for performance.

There is actually a range of angles of attack and flap deflection that will result in the forward foil having the same lift at at given speed. The boat can fly at a lower angle of attack with more flap, or at a high angle of attack with less flap. Because of the feedback from the wand, flap deflection is proportional to flying height.

Pitch control allows the pilot to change the trim angle of attack in much the same way that moving fore and aft to change the load on the aft foil does. With pitch trim control, you have an extra degree of freedom to mke it possible for both flying height/flap deflection and weight to get back to the center of their range instead of being at one extreme or the other when flying fast or slow.

 

I have never had any wand problems with my boat. Granted I brought a boat that was allready set up well off an experienced Moth sailor, but once set up properly this system works fine (Illet wand set up).

Bringing in a manual control system is only going to make sailing these boats more difficult. keeping an eye on competitors, sail trim, breeze, rudder setting now lets also throw in manual ride hight control. After every tack and every gybe there's one more thing that the skipper has to contend with.

Off the foot would be hard. 98% of the reach my toes are hanging from the straps the only time they are out, is when i'm tacking. Down wind body movements change and at between 16-20+kts even the slightest adjustment through mistake can end in disaster.

Grant

 

Pair of Stevo's...

So, how did foils end-up on an otherwise content class of little boats?

Rules are written, rules are rewritten. I know it's potentially upsetting, but that's the way it works for all things in life. Go watch your local City Council some evening and see how many rewritings of the rules take place.

Take a look at any routine election in a Democratic country and see how many rule changes are being voted upon each election year.

Have any of the Moth Class rules been altered to reflect the use of foils and rudder gantries which didn't exist before the foil thing happened on the scene?

Don't have F1 budgets and have written the rules to accommodate that fact...? What do you call the introduction of all-carbon boats with sophisticated and expensive foils, if not a quantum leap in expense over the previous boats in the class?

Ask Doug, change due to technology is inevitable. If you think it won't happen in the Moth Class... well, that must be a comforting thought.