International AC 62RC Class

[Doug Lord]

This is an invitation for all interested to join in building a new radio controlled racing class based on the AC 62, the new boat for the 35th Americas Cup. The boat will be loosely based on the full size rules with a length of 62". The final decisions on most of the rules have not been made yet. The rules are being disscussed on the rc groups forum here:
http://www.rcgroups.com/forums/showthread.php?t=2180752

Your input would be most welcome! There is no rush in getting this project together. Issues regarding transport, wings, hydrofoils, electronics and exactly how the class rules should be worded need to be worked out. One of the most important things, in beginning this class, is to have the focus on developing a race boat for sailors who want to race, not necessarily build or do development work. So one of our considerations is to have "one design" rigs, possibly one design foils and IF a movable ballast system is used it would probably also be one design. The idea is to make the Class as inclusive as possible and have first class performance attainable by all who participate.
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I'm putting together a smaller 51"(1.31m) prototype to test rigs and foils. It is a 15 year old platform for a Formula 48 cat that just had each bow extended. The foils will be UptiP foils, based on the foil invented by TNZ with refinements similar to the Flying Phantom ,GC32 and the Fire Arrow Test Model where the foils have been very successfully used as ama foils. The foil design on those boats reduces rake adjustment to ,basically, "set and forget". I'm going to test the foils using radio adjustable rake and, for the sake of simplicity, a four foil configuration will be tested instead of retracting the windward foil. Retracting the windward foil may also be tested. The rake-adjust system will also allow the testing of downforce from the windward foil, though the boat is probably too narrow for that to work efficiently.The foils may be one design, to encourage participation, or the rule may stipulate that custom foils can be used as long as they are available to all class members. A movable ballast system will be tested. A wing rig will be used and will be one design and soft rigs will be allowed initially. This is to ensure that the wing rig is actually faster than the best soft rig.
I'm familiar with the history of RC multihulls, but this is the first time in history "we" have had a foiling multihull class sailing for the America's Cup! I truly believe if we work on this together that we can come up with an historic RC foiling multihull.
So I'm using my 15 year old 51.5"(with extended bows) platform to put together a foil system to prove that a simple system that anyone can use is possible. I don't expect much to happen until there is video of this prototype foiling-which it will do in very light air.

Picture of the 51.5" D4Z /AC 62 prototype under development now:
click--

 

[oldsailor7]

Sexy looking Beast Doug.

 

[Doug Lord]

Thanks Paddy. It's flat amazing what those extended bows did for her appearance compared to the 15 year old bow. But the real deal will be taking what I've learned from the Fire Arrow ama foils and translating it to a stable main foil on the cat. That will be my "graduate" thesis on UptiP foil design and application. Very exciting-especially since I think I can do it!

Left-original, right-new:

 

[Doug Lord]

Great news! A very accomplished and well respected German rc multihull builder and designer has just said this:
Great stuff and they sail in a way that has never considered to be possible before. Even within the AC everybody thought that they would foil downwind only. After half of the races they just started to foil upwind as well and it paid off. So it turns out that not believing might be wrong and so maybe a RC boat could also foil around efficiently although I cannot imagine right now.
HOWEVER I am still too conservative or call it not sufficient idealistic to believe that the RC boat could do almost the same. I heard from the C-Class designers that it is much more difficult to get a smaller platform to foil in a stable mode. And that was C-Class cats, not our little monsters. BUT I promise at the same time, that as soon as I see some good efforts and first results I will be the first to join the class and build the first boat here
Keep it up Doug! I love the enthusiasm.

Chris (Emphasis added by DL)

 

[Doug Lord]

International AC 62RC Class Rules Proposal

Here is a rough outline of the tentative rules:

1) LOA-62.3"(5.19' / 1.58m)
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2) Beam-43" (3.58' / 1.09m) See rule #6 below.
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3) Sail Area--Total: 2800sq.in(19.44sq.ft. / 1.81sq.m.)
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4) Minimum Weight:
--- Boat-no ballast system-13lb. / 5.91kg
--- Trapeze Power ballast system: (may be used or removed at will)
a. Max Ballast 3.5lb / 1.59kg. (plastic coated lead may be used in any amount up to this maximum)
b. Ballast Moving System: RMG 380 winch or equivalent
c. Ballast Rack-open design-see prototype-max weight-1lb/ .45kg
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5) Radio-8 channel max
a. telemetry legal
b. video-open
c. electronic gizmo as proposed by Magnus legal if strict one design in terms of function.(see rcgroups link above and look for posts by "blunted")
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6) Transport:
a. boat must fold or slide apart for ease of transport
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7) Materials and Construction:
a. Vacuum bagged carbon legal
b. autoclave illegal
c. this needs to be carefully considered so that materials and construction methods are available to everyone so that "home builders" will remain competitive with professionally built boats.
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8) Foils-should be strict one design. The reason for being strict one design is to ensure that anyone that wants to race one of these boats can do so without engaging in a foil development process. There may be a one year grace period to consider what foil design best suits the interests of the class.
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9) Rigs:
a. Following the full size rule, the rig shall be strict one design.
b. A trial period shall be agreed whereupon soft sail rigs are raced against solid wings. Consideration shall be given to allowing both soft sail rigs and wings as long as the areas are identical-that is solid wings shall be strict one design and soft sails shall be strict one design.
c. Mains/ wings must be reefable or consideration given to a maximum of 3 alternative rigs.
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10) Hulls and Beams are open within the parameters of the rules above. (added 10/2/14)
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This is just a proposal-everything including length is open for discussion.

 

[Doug Lord]

Here is the final, version one UptiP foil design for the D4Z -AC 62RC Prototype compared ,on right, with the UptiP ama foil on the Fire Arrow Test model:
click-

 

[Doug Lord]

International AC 62RC Class Rules

This is a few thoughts I have in response to a comment on rcgroups:

I think the rules can be a box rule with some one design components like maybe the rig(Wing-I'm leaning toward leaving a soft sail rig open within the max sail area rule), the foils and the foil control system. My reasoning is that there aren't too many people around that have the skill to design foils or a foil control system or a solid wing.
By making these items one design it may ensure that more people will be interested because they don't have to worry about these components.
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I think hull design and beam design can be open within the minimum weight rule.
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The first priority for the class is to get a working prototype that will:
a. foil in a 5mph breeze or less( idea-class races restricted to races where the boats can foil?)
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b. foil upwind and downwind,
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c. the goal should be to have the boat able to tack and gybe on foils. This will be a combination of design and skipper skill. The prototype will determine if this is realistic or not.
==============================
While I am modifying a D4Z platform to serve as a prototype to prove the foil system, there is no reason at all while anybody else that wants to cannot go ahead with their own prototype at the same length as mine (51.5") or 48" or 62.3".
I will share all the technical stuff I have. No one should underestimate the difficulty of doing this-it has never been done before. But I'm completely confident that it can be done-mainly because of my successful application of UptiP foils to my Fire Arrow trimaran.
What we will wind up with is the first America's Cup Class RC catamaran which will be a showcase of modern technology. It will not be "cheap" to do this well, but it shouldn't be outlandishly expensive for what it is.. It will be fun to sail, I mean fly, and it should be very, very fast. It will take practice to learn to race well, but that's the fun part.

 

[Doug Lord]

Principles that should guide the development of an AC 62 RC Class-just my opinion, though I feel quite strongly about the following.
A sort of Constitution of the America's Cup 62 RC class........
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I believe that the most important parameters for the new class should be, in order of priority:
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1) A high performance hydrofoil sailboat, that as much as possible replicates the foiling system used by the AC 62 Class, preferably using UptiP main foils in a three foil configuration like it's big sister. A high performance radio controlled hydrofoil sail boat that is designed as a racing boat, not as a development boat,
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2) A high performance radio controlled hydrofoil sailboat that is capable of foiling upwind and downwind starting in as little as 5mph of wind,
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3) A high performance radio controlled hydrofoil sailboat , that through skipper skill and boat design, can be capable of gybing while still on hydrofoils and where tacking on hydrofoils may be a developed skill.
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4) A high performance hydrofoil sailboat capable of being sailed by experienced rc sailors or by experienced full size sailors with practice.
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5) The design and rules for a boat as described in 1-4, should be done in a manner that facilitates the goals in 1-4 in the most cost effective manner.

 

[Doug Lord]

Two guys are starting now to build AC 62RC boats to a hull design by John Xman(see below). Building plans are posted on rcgroups. Two of us are building smaller boats to the AC 55RC class where there are only two rules: Max length=55" and the boat must be a cat. It's cheaper for us to start since we have existing platforms. We're going to test foils, wings and the "Trapeze Power Ballast System" at a lot less cost initially. Mini 40 and Formula 48 cats are legal.....Here are Johns drawings:

 

[jiggerpro]

good job your pioneering a new Rc trend

 

[Doug Lord]

International AC 62RC Class / AC 55RC Proto Class

Thank you-but there is a long road ahead.

 

[Doug Lord]

D4Z AC 55RC -the AC 45 of the AC 62RC Class...

Here are a few shots of the D4Z proto with some paint and primer. It's been decided that there will be an "AC 55RC" class that will be like the AC 45 in the full size Americas Cup. There are only two rules: it must be 55" LOA and it must be a cat.It came about because two of us had existing platforms we wanted to use as prototypes to test foils and rigs,etc. There is another guy already sailing his version of the AC 55RC-you can see it on the rc groups thread(see the first post for a link).

 

[Doug Lord]

Curved Twisted Surface Piercing T-Foil

I've come up with a new type of foil based on my recent work on the Fire Arrow and originally sparked by an idea Mal Smith had for a surface piercing foil on a Laser monohull.
Here's how it will function on the cat:
Both daggerboards will be canted 10 degrees. The minimum angle of heel for the windward foil to be clear is about 4.5 degrees. This,in essence, is the same as retracting the windward foil but with no electronics or increased skipper workload to hassle with.
The foil is twisted to develop high lift at low speed with the high lift sections clearing the water at speed. Design takeoff is about 4.75mph(4.1 knots)-may be raised for racing but would be maintained for a one design version of the D4Z. The idea is to be able to foil in almost any wind condition from 4-20+. When this foil reaches above about 6mph the windward foil should come clear. Above 8mph the foil surface will be about 30% less than a fully submerged t-foil. The same foil will work with and without the Trapeze Power Ballast System.
Next job is to assemble the new version of the Trapeze Power Ballast System, then build and install the foil trunks and build the foils. Total area of the two main foils is slightly more than the F3 main foils(18.6 vs 17) but SA per sq. in of foil area is the same.
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The far right working sketch shows the rudder and "L" foil. The "L" portion is below the mainfoil so that if the surface piercing main foil(s) breaches the surface the rudder foil will still work. The rudder is not canted to keep it clear of the daggerboard wake. The "L" droops to work better at a small angle of heel. While this is a new type of foil as, far as I know,whether it's better or even as good as some existing foils has yet to be determined. The most important part of this concept is simplicity and that is the major advantage it has for an RC model. Disadvantages include probable multiple surface penetrations which, on full size foils are a bit draggy. On a full size foiler these foils would likely ventilate causing a loss of lift. On the model ,ventilation is very unlikely, probably because of the Reynolds number they operate at but in 15 years of sailing RC foilers I have never seen a case of ventilation. So, it's worth testing this configuration and easy to switch to UptiP or wand controlled foils for racing.
The shape of the CSPT- foils is not accidental and was specifically designed for the D4Z with the portion of the foil within a few inches of the tips being twisted to aid in takeoff at low speed. At higher speed one or both tips may breach the surface. For better upwind performance the daggerboard extends below the foil. And with higher speed the windward foils are clear of the water starting as early as a 4 degree angle of heel. For "advanced" versions of this system or on full size boats the lower portion of the daggerboard would retract into the upper portion and the whole foil would retract up to the bottom of each hull making transport easy.

Click on the working sketches for the best view:

 

[Doug Lord]

AC 55RC(D4Z)-the "AC45" of the AC 62RC Class

A bit more progress on my boat: these pictures show the set-up of the "Trapeze Power Ballast System" which is a movable ballast system I developed
about 19 years ago for RC sailboats. On the D4Z the system will carry up to 3lb and move from center to max out in about 1.5 seconds.
The system sticks out about 24" from the side at max RM and the weight is 48" from the center of buoyancy of the lee hull and 49.25" from the center of lift of the lee hydrofoil. As the weight moves out it is supported by a "trapeze" wire going to the shroud attachment point on the mast:

--The third and fourth pictures are of a complete Trapeze Power Ballast System on a scow model. It was also used on a Melges 24RC model and a microMOTH--
click for best view-
--UPDATE-11/23/14- the last three pictures show the radio box that will fit up against the front of the forward cross arm:

 

[Doug Lord]

D4Z / AC 55RC (AC 62 Proto)

Here is the start of the mold(not plug) for the CTST-foil* for the experimental main foils of the D4Z/AC 55 RC :
* Curved Twisted Surface Piercing T-foil
click-