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

Foil t/c

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Thanks,Paddy! I couldn't go that low without increasing the chord and wetted surface a lot? 6-7% on a lot of IOM's but they have a fairly large chord for the length(relatively low aspect).

 

Fire Arrow-upcoming ama foil mod

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It was always part of the plan to have the ama foils adjustable up and down on the full size boat-I was even going to do it on the Test Model by radio until the complexity and extra weight changed my mind. But I've decided now to extend the ama foils up to about 6" to improve the way they work in waves. The idea would be to manually adjust the foil down in heavy conditions with waves. If you look at the very first fully foiling video you can see the boat roll into a wave trough as a powerboat wake comes thru on the stbd. stern quarter. She stays on foils but on the full size boat ,in those conditions, the foils would have been lowered.
By extending the length of the model foils I'll be able to test whether or not the added depth in wave conditions helps or not. It is possible that when the ama foils are extended the wands could be lengthened to allow the main hull to fly higher keeping the extended windward ama foil clear of the wave tops by allowing the boat to sail at a greater angle of heel.
This won't be done for a while.
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The mod will drop the foil straight down from this position about 6" max and will allow manual adjustment:




Note the position of the port ama foil relative to the water:

 

Fire Arrow Foiling System Testing and Development

In addition to the ama foil extensions mentioned in the previous post one of the things I want to test when possible is a surface piercing T-foil to possibly replace the wand controlled mainfoil on the Fire Arrow. The most significant negative about using such a foil is the fact that,at least initially, the foil will not develop downforce which is a tremendous advantage of the wand controlled main foil. Downforce can potentially double the RM and do it instantly and automatically in response to gusts. But testing the boat w/o that facility will be interesting and be a much simpler system. There is a way that the foil could be designed that might allow downforce using and upside down asymmetrical section in the center of the surface piercing T-foil(bordered by fences)-but that will have to wait.

Surface Piercing T-foil with iFlaps to allow extra lift at low speed for earlier takeoff in lighter wind. Drag from these flaps disappears when the boat speeds up reducing the wetted portion of the foil:



iFlap(intrinsic flap) illustration-used on one Fire Arrow foil for next Tests-appears to work. The Bat Foil replacement for the Fire Arrow mainfoil would have two iFlaps-one on each side to improve low speed takeoff:

 

Perth man, you should start your own thread, really interesting.

 

Fire Arrow Foiling System Testing and Development/ aeroSKIFF

I have been interested in Hugh Welbourn's foil system that he developed for the Quant 23 since I first saw it. Interested enough to build an RC Test Model of the concept -albeit on a bit of a different hull than the 23. In my work on the model and on designing the foils for the model I've studied the Q23 a lot and thought about those foils a lot. The really cool thing about the foils is that they don't draw much water-when foiling or when sitting still. Doesn't much matter on the 23 because its a keel boat with a fairly deep fin keel.
But it could matter a great deal if the foils were incorporated in a boat like the Fire Arrow(but not the Fire Arrow). By "like" I mean a trimaran using the Q 23 type planing/surface piercing foils and using the foil configuration of the Fire Arrow on the main hull.
For a full size boat this is what I've figured out so far:
1) On a small tri using the Q23 type foils the beam of any version between 12 and around 18' could have a trailerable 8' beam(or less) with the foils retracted. That's compared to the 22' beam of the 19.5' version* of the Fire Arrow and the 17' beam of the 12' version.
*Test Model is a scale model of this version.
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2) For a single handed version using the Q23 foil concept the foils when deployed would stick out 4-5' on each side, and be designed so that when foiling only the lee foil was wet. The foil would draw no more that 1.5-2' at any time while flying(if that).The crossarm dihedral would be similar to the Fire Arrow and designed to keep the weather foil clear of the water. The lifting foil on the daggerboard would be setup to draw a max of 2-3'-and the rudder about 2'.The amas would be relatively small and the whole boat targeted for about 250lb all up. If you added 50lb to the hull weight , with crew weights the same, the pounds per sq.ft. of upwind sail area would be the same as a Moth-about 2.7-2.8! But 250 is a reasonable target.Sail area would be about 176 sq.ft upwind and double that downwind.
A two person version would be slightly heavier but capable of carrying 252 sq.ft upwind.
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3) the beauty of applying the Q23 type foils to a tri is that it can have tremendous righting moment on a relatively narrow(street legal) platform that requires no assembly before sailing and because of the narrow platform beam(compared to the Fire Arrow and most other tri's) and the relatively small amas, it can be significantly lighter than a catamaran. It would still have the advantages of the Fire Arrow in that the crew (single or double) would sit on the windward side of the cockpit w/o trapezes and without having to sit out on the ama-no hiking. And it would have the advantage of the wand controlled lifting foil on the daggerboard for additional righting moment in gusts and stronger breezes as well as very early take off in light air. Or the option of a surface piercing T-foil instead(no downforce but early takeoff similar to the wand controlled main foil).
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I'm convinced a shallow draft foiler like this has tremendous potential especially in Florida and other areas where shallow draft is a huge benefit.
And the configuration lends itself to being light weight and easy to handle on the beach. I think we might call it aeroSKIFF.........

Pictures show the Quant 23 foils deployed while sitting still-very shallow, retracted and deployed while foiling. The new concept would have the same main hull foils as the Fire Arrow-only much less draft. The crossarm dihedral would be similar and the boat would be designed to sail at an 8 to 10 degree angle of heel similar to the Fire Arrow:
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Lithium Battery replacement

For drones and radio control Test Models, this power source may replace lithium batteries in the not too distant future: http://www.gizmag.com/cella-energy-fuel-cell-drone/41718/

 

One Metre in production

Happy to report that our production One Metre tri is performing well, using our kinked foils. For its first putting we used V foils on shafts, but immediately swapped to kinked foils and the transformation was a revelation

https://www.youtube.com/watch?v=nzT...r5vr4unf4irg0k&google_view_type#gpluscomments

With the exception of not having any hold-down on the windward side, our kinked foils are working really well, providing bite to windward and the right degree of lift. The boat flies a bit high when foiling so we'll shorten the foils by 1cm and see what that does.

 

One Meter Tri

Looks good, Ian. How much are you selling it for and how does one go about buying?
Since the only one meter multi rule that I know about is the Multi One rule ,why not increase the beam and grab some extra righting moment? I think when Dick and I did the rule we allowed a 48" beam on a multiOne.

 

One Metre foiling tri

Our estimate of kits prices are in the attached file. A total of USD632 for 3 hulls, 2 cross beams and 2 kinked foils with foil cases installed, main hull deck cutouts but no fittings.

We opted for the One metre beam for ease of transport. It lets a one-piece trimaran fit inside an average family estate car with rudder and foils fitted - no need to remove them each time you travel. Certainly a wider beam would give more power and foiling stability but we want it to be user-friendly, so a simple box rule: If the boat fits inside a box one metre long by one metre wide, then all good. no need to measure depth of mast or sail area. If the rig is too big the boat simply cartwheels, so why waste time measuring it?

 

RC One Meter

Good luck with the boat!

 

G'day Perthmini40man,

I too reckon you should open your own thread. You will get a lot more people checking out what you've got if you were on your own. This thread is just endless re-cycling of pictures and summaries of what happened that long ago nobody can even remember.

Basil

 

Basil why do you even bother posting in this thread?

 

Fire Arrow Foiling System Testing and Development

Still no progress. I'm told that the builders are having permitting problems.
Seems incredible to me.......

The boat ready to go:

 

I'm only here to check evey month or so whats going on in with the famous Fire Arrow. And as of last month and the 12 months prior absolutely nothing.

 

Fire Arrow Foiling System Testing and Development

Well, that is an extremely inaccurate appraisal of progress with the Fire Arrow and clearly shows you've missed a lot. Seems like a waste of your time if thats all you've gotten out of your visits. Perhaps you should read more?