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

Fire Arrow Foiling System Testing and Development

Updated Fire Arrow System Advantages:
Note-the basic Fire Arrow Foil System is now working on Maserati, Gitana 17 and Banque Populaire with versions designed by Guillaume Verdier and VPLP.

One of the great advantages of using a properly designed UptiP foil on a foiling trimaran ama is SIMPLICITY: on the Fire Arrow the ama foil has NEVER needed to have the angle of incidence adjusted while sailing as is common on many UptiP foil applications. And if the foil is properly designed for it's application ,it's efficiency will be apparent. As shown in the pictures below the lee ama flies before the main hull, but as soon as the boat speeds up and the main hull flies the lee ama altitude remains the same. That illustrates that the lee UptiP foil is working PERFECTLY in two different load and speed cases.See pix "A" and "B" below.
The Fire Arrow uses a wand controlled main foil which controls the altitude of the main hull and the angle of heel of the whole boat. Further, and this is very important: the wand controlled main foil works with the single rudder T-foil in a bi-foiler arrangement and the two together control the ride angle of the lee ama UptiP foil. That prevents pitch excursions caused solely by the lee ama foil.
The way the mainfoil works is that as soon as the main hull flies the mainfoil begins to unload with the lee ama foil gradually taking the majority of load. That allows the mainfoil to work with the rudder T -foil to control the pitch of the boat with far more pitch authority than on a conventional tri. And, using a wand controlled(or similar) foil on the daggerboard allows the main hull to fly MUCH SOONER than it would if it had to wait for wind pressure to do it.
The mainfoil can also develop substantial downforce* increasing the righting moment in response to gusts. All this is done 100% automatically making for a simple, robust system that requires ZERO crew attention!
* with downforce, the main foil works similarly to a Moth foil with Veal Heel, generating a component of lift to windward.See illustration below.
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The vertical portion of the ama foil is at +3 degrees AOI. The vertical portion of the daggerboard is at zero degrees. So the UptiP ama foil is developing lift to windward to allow leeway coupling and develop lateral resistance for the boat particularly upwind.
In stronger conditions, when the main foil develops down force( upwind), the leeway components are greater than the vertical portion of the UptiP foil can effectively handle, there is a small extra component of lift to windward(due to downforce)-while the vertical portion of the ama foil is still working at 100%. The daggerboard is designed to be unloaded by the lee ama foil to reduce drag and facilitate leeway coupling.
However, it should be pointed out that the ama foil will still provide substantial vertical lift with little to no leeway coupling-like can occur off the wind. Lift substantially(and automatically) increases upwind because of leeway coupling.
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Testing clearly shows the progression of the boat to full foiling from the problems encountered at the beginning-the last video is 100% proof that the foil system worked perfectly!
See the 9/16 video of Maserati to see the basic Fire Arrow system in use on a 70' tri. Also see the recent Gitana 17 video below showing the first full size trimaran designed from scratch by Guillaume Verdier to use his version of the basic Fire Arrow Foil System.

We reached a major milestone with the boat foiling in a 5 mph wind while using two different altitude control systems simultaneously. July 24th, 2014 was a major accomplishment for the boat after a great deal of design and development over 4 years. Each attribute below was proven during the month and a half testing in 2014 culminating in the 7/24/14 testing where the foil system worked exceptionally well.
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Proven attributes of the Fire Arrow Foil System:

1) allows an oversquare trimaran to foil in very light air and be stable in heavier air,
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2) allows full foiling upwind and downwind completely automatically without any adjustments by the crew,
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3) allows for retractable foils controlled from the cockpit,
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4) allows the lee UptiP ama foil daggerboard portion, with an AOI of +3 degrees, to unload the daggerboard(AOI zero degrees) for reduced drag and enhanced leeway coupling. The ama foils do not require constant rake adjustment-basically set it and forget it.
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5) the foil system has considerably greater pitch authority than any conventional trimaran,
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6) allows automatic control of the angle of heel of the whole boat,
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7) allows automatic control of the ride angle of the lee ama UptiP foil.
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8) allows mainfoil to automatically unload as the mainhull flies ,dramatically reducing drag.
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9) allows automatic gust response with instantaneous increases in righting moment (automatically) as required through mainfoil downforce.
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10) allows a "Two Stage" ama that provides back up buoyancy if needed but allows the part of the ama that would normally make incidental contact with the water to be as small as practical.
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11) allows the use of UptiP ama foils without the requirement to retract/deploy a foil with each tack or gybe-a requirement on every other multihull using uptip foils. Foils can stay in their deployed position without retracting except for shallow water/beaching.
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12) allows use of two different types of altitude control simultaneously.
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Maserati:


Gitana:


Banque Populaire:
View attachment 136866

 

Tansl, this is a picture of my fathers 60' Larchmont "O" boat-a classic beauty and a lot of fun to sail according to Dad. For the first year the boat didn't have an engine!



Georgia on the cover of Yachting mag-Dad is the guy standing in the white shirt. He had no idea that this picture was taken until the magazine came in the mail!

 

A beautiful boat, wonderful.
I'm passionate about technology but the admiration that these big sailboats give me, I can never feel it for the foilers. I also love airplanes and F1 cars but you can not mix these ways of "moving" with sailing.
Speaking of hulls for sailboats, I prefer that the dominant technology is hydrodynamics, although it is not the only one (I do not know how to express it correctly, but I hope you understand what I mean).

 

They'd have had a better time in a recumbent cycling position: more comfortable, better view and there would also have been a lot less drag.

 

They were probably put in the position where their effort was most effective.
But it is amazing that the crew is composed of only 30% of sailors who, in addition, act largely following the instructions of people working on the coast with a computer.

 

Here is a competitor to you in class: trimaran model foilers

 

Cholsson, thats a new racing tri by Ian Holt. There is more about it in this thread:
Foiling radio control trimarans https://www.boatdesign.net/threads/foiling-radio-control-trimarans.55840/page-3
It's not really a competitor for me since my boat is an exact scale, one-off, experimental test model of a 19.5' fullsize trimaran rather than being designed as a racing model. My boat is not designed or built to any class rule and is 1.4 times as long as Ians, about twice as wide and 3 times heavier.
Ian has a number of boats and does a really good job. In the pictures you show he is testing his new "S" foils.

 

Doug Lord, how to get the scene of the picture so that the wind resistance of the hulls is as small as possible?

Have you ever considered this possibility?

 

The real NZAC? ---go here for more:
AC 36 Foiling Monohulls https://www.boatdesign.net/threads/ac-36-foiling-monohulls.59160/page-11#post-818385

 

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Tansl, I think the new Inshore Volvo render by Doug Shickler and partners is the coolest cat foiler design I have ever seen and without a doubt the one with the least aero resistance. And ,no, I never considered either----see the aero-hydro thread for a great deal of technical info:
Volvo Inshore Foiler--Technical Design Information https://www.boatdesign.net/threads/volvo-inshore-foiler-technical-design-information.59460/

 

Mr.Manuel Ruiz de Elvira, one of the boat designers of the America's Cup (he has taken part in the designs of several winning boats) said that it is in this direction that the designers of foilers are working at the moment.
I am not an authority on the subject but I do not have much faith in the "new Inshore Volvo render".

 

You really don't need "faith"- just read the technical data............

 

Precisely because I have read them and I have seen all the information available.

 

WOLF---daughter of fire arrow
Updated 11/20/17 specs, notes and pictures :

NOTE: I'm sure various changes will continue until(and after) the boat is launched-that's what development is all about.

WOLF Specifications:

LOA 15.458' (4.7m)
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Beam max-18.75' (5.72m)changed 3/22/17
-beam folded-8' (2.4m)
-main hull beam on deck: 2.625'(.8m)
-main hull beam at wl: 2.125'(.65m)
-main hull L/B at wl:7.27/1 (planing)
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Two Stage Ama-11.5' (3.5m) changed 3/22/17
-ama hull-7.7' (2.35m)
-ama hull beam .58' (.18m)
-ama hull L/B=13.3/1 (planing)
- curved piece-5.9' (1.8m) changed 3/22/17
- overlap- 2' (.61m)
- two stage ama canted bottom out 12 degrees.
- two stage ama buoyancy(not including crossarms)=252lb(61%)
-changed 7/27/17 : Note: planing two stage ama is designed for incidental contact with the water. Not to be sailed "on" on a regular basis since foils provide vertical lift. The planing surface is used to reduce drag when the ama does make incidental water/wave contact at speed. Hydroptere adopted stepped,planing amas after first starting with a "normally" shaped ama.
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Weight:updated 6/12/17
-boat-target-275lb/ MAX 299lb (135.9kg)changed 6/12/17
-crew-215lb (97.7kg)
-sailing/flying weight: target-(215+ 275)490lb. (222.7kg.)
MAX-(215+299)=514lb(233.6kg) changed 6/12/17
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Sail Area: updated 6/12/17
-main + jib= 217sq.ft(20.17sq.m)changed 6/12/17
- spin/screecher about 150 sq.ft(13.9sq.m)
-Sail Loading-MAX weight in pounds/SA in sq.ft.:
--upwind=2.37 changed 6/12/17
--downwind=1.4 changed 6/12/17
--max pressure before depowering= 1.76lb/sq.ft.
--max heeling moment=5402ft.lb.*
* not including asy/screecher
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Seating: there are two levels of very comfortable seating on each side of the boat. The upper level has a sliding and removable seat back for great back support while flying. Some degree of adjustment may be incorporated in the lower seating level. See the pictures below for a rough idea of the basic seating plan. added to spec sheet 9/16/17
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Designed flight angle of heel: 5.5 degrees to 15 degrees. Standard 10 degrees.
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Main hull flight altitude at centerline: .5'(.15m)---2'(.61m),Standard 1.19'(.36m)
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Righting moment at target weight(not max weight) : updated 6/12/17
-crew 215 @14'= 3010ft.lb.( 4081N/m)*
-boat 275 @ 8.7'= 2392.5ft.lb.( 3243.79N/m)
TOTAL RM= 5402.5ft.lb (7324.8N/m)
Downforce from main foil(if used) approx. 1500ft.lb.(2033.7 N/m)
* N/m conversion done from online converter
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Foils:
-uptip foil in each ama, adjustable AOI and up/down(mostly retractable). Tentative AOI-3-5 degrees over twisted foil. Asymmetrical section.-- added 3/25/17
These foils have a "droop" to the tip first used on Fire Arrow which was the first trimaran to combine a droop tip with an UptiP foil on any trimaran ever!9/22/17--see posts 2577 and 2587 for the Fire Arrow "droop", WOLF "droop" and the Gitana 17 ama UptiP foil tip "droop".
-mainfoil wand altitude control, adjustable AOI(nominal 2.5 degrees),up/down(retracts flush with bottom). Symmetrical section.-- added 7/28/17
-rudder T-foil, adjustable AOI(nominal zero degrees),retractable.
-Note that in their smooth water configuration, the uptip foils can be left down at their flying position when the boat is pulled up on the beach! And, of course, as mentioned before these foils do not have to be raised or lowered each time the boat tacks or gybes. This is not found on any other boat using uptip foils.
The Fire Arrow Type/ WOLF uptip foils are shallow draft compared to most other types of hydrofoil. added 3/29/17
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Planing surface on lee ama hull is designed to be flat when main hull is just clear of the water(6") and that will occur at an angle of heel of 12 degrees.(Depending on foil lift-3/25/17)

pictures updated 11/20/17:

 

Consult other opinions, perhaps more authoritative than mine, in the thread: Volvo Inshore Foiler--Technical Design Information https://www.boatdesign.net/threads/volvo-inshore-foiler-technical-design-information.59460/#post-818411