High Performance MPX Foil/Self-righting Trimaran-The Test Model

Model Yacht Sail Materials

Thanks Doug for those additional references.

One item that I had in mind when I was considering this 'model test' was to keep the flying shape of soft sail material shape/settings out of the equation. That is why I was originally looking at more 'rigid' materials for my 'just rig models'.
http://www.boatdesign.net/forums/sailboats/scale-model-testing-sailing-rigs-outdoors-52977.html#post731871

But I am open to any constructive criticisms.

 

Fire Arrow Foiling System Testing and Development-FA70 Concept

UPDATE-4/27/16--This will be a rough comparison of the Fire Arrow advantages scaled up to 70' as compared to the Gitana MOD 70. Its a rough comparison because no design work or engineering has been done for a 70' version but, as will be seen below, many of the advantages of the small boat(post 2297, above) would likely translate to a larger version.
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What would be different than the Test Model:
1) the amas would not be a "Two Stage" ama(page 129, post 1922) as described in the previous post and the crossarm dihedral would not be as high. However, the ama would not be the same as Gitana(for instance) but would have about 150-200% total buoyancy(about 85% ama + curved piece on the small version of the Fire Arrow). If you've seen the latest(last few years) version of the Hydroptere amas you will have noticed(maybe) that they are stepped planing hulls designed for incidental contact with the surface at high speed. The Fire Arrow 70 Amas would be a stretched out version of the Hydroptere amas in that they would have lots of buoyancy but would also have stepped planing hulls designed specifically for low drag incidental contact with the water at high speed. They would not be designed to be at their optimum at slow speed but since the boat would foil in light air it won't matter.
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2) the main hull would not be the same as the small Fire Arrow either-it would have a much higher L/B ratio but consideration would be given to reducing drag due to incidental contact with the water at speed while retaining relatively low drag at low speeds.
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Comparision of FA70 to Gitana MOD 70 Foiler:
1) Gitana LOA=21.3m(69.8') X 17m wide(55.76')
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2) Fire Arrow 70=21.3m(69.8') X 25.9m(85') wide.
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Now, if you consider that boats like MOD 70's and other large tri's want to be able to fly the main hull or, at least, have it just skimming they have to juggle maximum sail area, weight and overall beam to be able to do that.
If they get the beam too wide for the sail area then it will be difficult to fly the main hull. So they have to strike a compromise that will allow the hull to fly/skim in the widest range of wind possible. And, of course, foilers want the main hull clear as much as possible.
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The Fire Arrow 70 would start out with a wider beam than the Gitana type(similar proportions to Hydroptere, except that the center of lift of the ama foils is substantially further outboard than it is on Hydroptere). The wider beam is possible because of the unique features of the Fire Arrow foil system.
1) the boat would have a T-foil on the daggerboard utilizing an all moving foil/board combination or a flap on the main foil. The foil would control the altitude of the main hull and the angle of heel of the whole boat. A wand type surface sensor, electronic sensor or manual/hydraulic control of the foil and/or flap would be used to actuate the foil.
Electronic or surface sensor systems would probably be best because they would automatically control altitude and could be simply adjusted for different conditions.
At any rate, since the foil would be designed to lift at least 80% of the boats weight at relatively low speed ,it could be easily designed to provide 40-60% of the boats weight in downforce which translates to much greater righting moment than possible with the Gitana type. Whats more this force would be created automatically making the boat much more stable in gusty conditions. Further, the amount of downforce , if any, could be completely adjustable. Structural analysis and engineering would determine how wide the boat can be and how much downforce can be allowed. But there is no doubt that the RM of the FA70 would be substantially greater than the Gitana type tri. And, again, the foil lift makes it possible to precisely design when* the main hull will fly which will ,undoubtedly , be in much lighter air than the Gitana type trimaran.
*what wind speed
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2) the Fire Arrow 70 would have a single rudder T-foil(vs two +a single main rudder on Gitana). This rudder foil would work with the main foil to control pitch for the whole boat. And since the mainfoil unloads as the flap approaches neutral, the pitch control authority would be greater than on a "normal" tri.
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3) A great advantage of the Gitana(and potentially Macif and Exocet) trimaran systems with an uptip foil and rudder t-foil on each ama is that in just the right conditions those boats should be capable of flying on just two foils. However, because of the nature of the Fire Arrow foil system it is likely to be faster because it allows greater power to carry sail from the get go, flies earlier and produces far more righting moment in stronger wind. And it can keep the main hull clear of waves in conditions where Gitana and Macif(Ultime-100') have shown that they will face frequent main hull wave contact.
At least that's what it looks like to me.


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This description will be frequently updated(5th-4/27/16) as the conception of a larger version of the Fire Arrow System becomes more clear.
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“There’s a full-on revolution going on in sailing, and more specifically ocean racing. We’re in the process of writing a new alphabet and we’re on letter A”
Baron Benjamin de Rothschild
http://www.gitana-team.com/en/b-9/multi70-edmond-de-rothschild


Fire Arrow Test Model, July 24, 2014, 5mph wind :

 

Fire Arrow-new video/still system

Just found the most perfect video/still camera system I've yet run into. This one would automatically track and shoot the Fire Arrow(or any other boat) while I sail! Can't afford it right now and shipping doesn't begin for a while yet but wow what a system!
Cost is about $500.....
https://shop.soloshot.com/

 

Seawall/steps

After almost one years delay they actually started today. Supposed to take just two weeks. Theoretically (all else being equal) I should be able to launch my boats right here when they are done.

Looking north from our dock-the seewall next door was done by the same company doing ours--




Looking south--




Today:

 

Fire Arrow Foiling System Testing and Development

I'm trying to come up with a relatively short but complete description of the advantages inherent in the full size version of the Fire Arrow design. This is another improved version(5/3/16) :
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The full size version of the Fire Arrow at 19.5' would have a beam of 22'. It would fold to be trailered.
This beam would be impossible without the foil system described below:
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Probably the most significant feature of the Fire Arrow is that it uses two completely independent altitude control systems for the first time on any trimaran:
1) UptiP ama foils(also a first for any size trimaran*) that automatically control the height of the ama above the water. These uptip ama foils require no adjustment whatsoever while sailing which is a tremendous advantage.
*used on this boat way before they were used on any other tri.
2) Wand controlled mainfoil on the daggerboard-controls main hull height above the water which, in turn, sets the angle of heel for the whole boat.The mainfoil also allows the main hull to fly in very light air.(5mph)
But its the interrelationship between the main and rudder T-foil with the ama foil that makes the system so significant. The rudder T-foil is a trailing foil and "follows" the main foil. Altitude and angle of heel for the whole boat are set by adjusting the wand length. The angle of heel can be set between 10 degrees and 17 degrees. The boat is extremely stable in pitch because of the bi-foil arrangement on the main hull-the daggerboard foil and rudder foil always work together to control pitch when the boat is foiling. But they also control the ride angle and pitch of the ama foil which can't pitch on its own-in other words the ama foil can't all of a sudden "go negative" and cause a pitch pole.
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3) A major advantage of the wand controlled mainfoil is the ability of the wand to cause the foil to create downforce which can add significantly to the righting moment of the boat. It is an automatic response to the boat heeling even a slight amount: the wand will cause the flap to go up as much as is necessary to restore the main hull to its designed flight altitude. That can add a large amount of righting moment to the boat.(40-60% of boat weight or a bit more)
The use of foil downforce has been well proven on the Trifoiler ,Rave, Skat and Osprey. And the drag caused by doing this is not as much a disadvantage as the extra RM is an advantage.
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4) Two Stage ama(see pix below) : the ama hull is attached to a "curved piece" that adds to the ama buoyancy in knockdown conditions. This "two-stage" design allows for a small planing hull with relatively low drag during incidental contact with the water but provides tremendous buoyancy during a knockdown-enough; combined with the high dihedral crossarm structure, to prevent a capsize in most conditions.
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5) Oversquare platform: the boat is 1.22 times as wide as it is long. A "normal" tri with that much beam would need at least 15mph of wind to be able to fly the main hull. But because of the wand controlled main foil, this boat will fly the main hull in as little as 5 mph of wind which opens up the effective wind range for the foiling system-way beyond most multihull foilers. An ovesquare platform, at the very least, needs foil assist and this boat goes one step further with a full flying foil system which allows the oversquare platform an extra margin of safety and improves it's power to carry sail throughout the wind range.
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6) Light Air Foiling: from a marketing perspective selling a foiler that only starts to foil in 10-15mph of wind is a mistake but that has been true of many multihull foilers. More and more boats are targeting starting to foil in lighter winds: The Whisper foiling cat and Quant 23 are examples of foilers whose designer/builder has made the commitment to start flying in light air. The Fire Arrow test model was designed to begin to foil in a 5mph wind 5 years ago and reached that design goal on July 24, 2014. The full size version will take off in about the same wind speed.
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7) Self-righting: the model was designed , originally, to be lighter than it is now (16lb vs 21lb now). The extra weight was due to the level of finish work done on the boat combined with an extension added to the transom before the first test sail. The boat is now sailing with the equivalent of 3 175lb crew plus 87.5lb of gear on the full size version. Foiling in light air with the extra weight has shown that the weight does not significantly affect light air foiling performance. If part of the weight was incorporated into the bottom of the daggerboard, it is highly likely the boat would be self-righting from a pitchpole or capsize. The high dihedral of the cross arms along with the oversquare beam and two-stage ama assure that capsize is virtually impossible even without ballast. Ballast assures the boat would be self righting with no crew intervention from a complete pitchpole where the top of the mast touches the water.

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Hopefully, I'll be able to get the help I need to build a 19.5' version of the Test Model which would be a very cool trimaran and would illustrate well why this system is such an advance in small trimaran design.
In the meantime, I'm planning on getting more video with the reefed rig and shorter daggerboard and rudder.

 

I thought this might be of interest to you Doug. A leeward type foil on a narrow trimaran model. It looks like the windward foil causes a lot of drag would be nice if it was retractable or perhaps a wider platform or more dihedral.

https://youtu.be/eY5z9kPsatw

 

Outward pointing foils-

Thanks Corley. Jim and I have discussed this a bit on rc groups and here. His foils are just prototypes using bent flat sheet aluminum-as soon as he is satisfied with their position and area he'll build proper foils. Jim is doing a lot of experimenting with outward pointing foils. I think these foils could have applications on full size trimarans particularly under 20' where when they're retracted the beam of the tri is street legal but when they're deployed the RM of the boat is much greater. See more here: http://www.boatdesign.net/forums/hydrodynamics-aerodynamics/outward-facing-j-foils-cat-54044.html
My latest test model based on Dominion(1898-first tunnel hulled scow) uses outward pointing foils patterned(loosely) after Hugh Welbourns foils on the Quant 23. Hugh's foils (and mine) are designed to work with the boat at an angle of heel and his windward foil is retractable. To reduce the rc complexity my version is designed to sail a bit higher and at a slightly greater angle of heel to keep the windward foil clear w/o having to make it retractable by radio. The D2 is also designed to be a self-righting foiler.
D2=Dominion 2-HW.... Build Log here: http://www.rcgroups.com/forums/showthread.php?t=2434531
D2 and foils partially finished:






CLICK- Dominion 2-HW / Quant 23

 

Fire Arrow Foiling System Testing and Development

I was very lucky to first conceive of the Fire Arrow foiling system back in 2010. I was excited about it then and I'm excited about it now. But it didn't just happen.
F3
I've done many years of research on foil systems and had the great pleasure of working with Dr. Sam Bradfield for one summer. He used a platform that I designed and built to test the foils for his 40' Skat. He also greatly inspired me and the winter after working with him I did the design and started building what would become the F3. Turns out the F3 was the very first production RC sailing foiler and the only one in the last 20 years to utilize Dr. Bradfields wand based foil system. Other things that were done with the F3 were the "Wing Tip Rig"(fully reefable)- a unique take on a square top that featured an adjustable upper outhaul and very thin foils with partial span flaps.


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America One
Back then(mid- nineties) I was very interested in seeing if I could develop an RC spinnaker system that would be fully gybable and set/douse very quickly. After about three years of development I finally got it together with a 50" "S50" prototype. I figured that the best way to show what the system could do would be on a one design America's Cup model. I came up with "America One" as the project name. Then I read that Paul Cayard was begining an America's Cup Campaign that he called "America One"! Well, I found a way to get in touch with him and told him about my plan and also about my spinnaker system. He was almost as excited as I was and agreed that my model would be the official rc model of the America One campaign.
I invited Paul to come to Sail Fest in Sanford Florida to race and to see my prototype. I picked him up at the airport and we got along very well-he is just a terrific person. The picture below shows Paul at to our Sail Fest booth standing next to the America One prototype with one of Pauls "America One "stickers on the sail. The pictures of the finished red America One model are below.



America One upwind with spinnaker retracted:



America One(blue) and Spinnaker 50:


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During this last 20+ years I've worked on a lot of projects including developing the Trapeze Power Ballast System, Wing Tip Rig, a canting keel system, spinnaker system, microMOTH project and others. All these have led to the Fire Arrow Test Model which is, to me, my most significant design and is as original today as when it was first conceived in 2010.
And 20+ years later, thanks to Scott Morgan, my sailmaker for helping so much, and to Rob Guyatt whose excellent winches(RMG) made the spinnaker system and Trapeze Power Ballast System possible! And thanks to the numerous other suppliers I've used more or less constantly since the early nineties.
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With a bit more model testing and some luck I hope to build a fullsize version of the Fire Arrow-as well as, someday, a smaller RC version for speed and fun.

 

Z foils

We have made our own version of the Z foil and first trials have been promising - have a look at this video. So far we have only made the port foil mould but we'll now go ahead and make an identical mould for the starboard hull. Our "Z" has a 9.5cm horizontal outboard section before the lift section of the foil commences. It appeared to work well in the strong gusts we experienced on Saturday. The waves on the lake were large for a one metre hull length but the boat coped well

The video is here:


https://www.youtube.com/watch?v=m2Fv9dc3DjA&feature=youtu.be

 

RC Foilers

Interesting, Ian! I'd think that the acute angle between the horizontal foil and lower angled foil might be draggy when the joint is in the water but it didn't seem to have much of a negative effect in those conditions. Could you make the joint with a radius?

--Just out of curiosity doesn't a foil like that take the boat out of the mini40 class? Why not go for a wider overall beam of the platform? I guess with the new foil you can gain RM and easily change foils to race in the mini40 class?

 

RC Foiler

Foiler at Flevo Cup in Germany. Don't know who the designer and or owner was:
http://www.rc-network.de/forum/showthread.php/537134-Flevo-Cup-2016-vom-06-05-08-05-2016/page7 Might have been Gerd Mentges or Mike Cook?

picture by orma 60 freak: (I think)

 

The small white trimaran is ours, built in Australai and shipped to Gerd Mentges. He won two of the races and finished 4th overall - not bad for a one metre tri racing aginst Mini40s. Apparently he also had fun foiling around at lunch time too

 

Sorry, correction. He came second in two of the races. I miss-read the score sheet

 

RC Foilers

Still a great performance! Congratulations to you and to him....

 

Flevo Cup video, nice range of designs on display in a range of conditions. A 2m tri would be really at home in the conditions on the windy day.

https://youtu.be/pB-JHximkN4