Fire Arrow Foiling Trimaran Test Model - Page 15 - RC Groups
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Feb 04, 2018, 08:31 PM
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Years ago we had talked about electronic stabilization and the tech just wasn't really there. Now a 3 axis controller like a Naze32 or CC3D is less than $20. One with a mag compass would be cool, but one with logging would be really interesting.

Almost wondering if one should log a normal tri to see what the forces were like, then work backwards to see how much stabilization is needed.
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Feb 05, 2018, 08:26 AM
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Fire Arrow

Lots of good stuff available but one thing may still be missing: an electronic means of altitude control or at least an electronic means to measure small amounts of altitude over water accurately that could be tied into a servo. Thats the problem with the Fire Arrow -the wand is still the best solution for the mainfoil altitude control as best I can tell.
On Fire Arrow S the ama foils don't need any altitude input -they will be simply shifted between takeoff AOI and "cruise". But the mainfoil needs altitude input to work electronically.
Even the SuperFoiler doesn't require altitude input-the foils are controlled manually and moved electronically.

Last edited by DLord; Feb 08, 2018 at 03:23 PM.
Feb 13, 2018, 11:15 AM
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Fire Arrow Tech

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.
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.
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.
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,
2) allows full foiling upwind and downwind completely automatically without any adjustments by the crew,
3) allows for retractable foils controlled from the cockpit,
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.
5) the foil system has considerably greater pitch authority than any conventional trimaran,
6) allows automatic control of the angle of heel of the whole boat,
7) allows automatic control of the ride angle of the lee ama UptiP foil.
8) allows mainfoil to automatically unload as the mainhull flies ,dramatically reducing drag.
9) allows automatic gust response with instantaneous increases in righting moment (automatically) as required through mainfoil downforce.
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.
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.
12) allows use of two different types of altitude control simultaneously.

Maserati video:
Maserati Multi70 ocean-bound and in full flight (1 min 15 sec)

Gitana 17 video:
Le Maxi-Trimaran Gitana 17 vole - Le Havre Bretagne Tele (3 min 31 sec)

Downforce + windward component:

Fire Arrow

Gitana 17
Last edited by DLord; Feb 14, 2018 at 08:01 PM.

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