Question

[mholguin]

Just a quick question:

Are Remote Controlled sailboat designs discussed in this board?

[Tim B]

The general design concepts are the same for all yachts, and often these are discussed. Very little is discussed that is specific to RC sailing boats, though. It is worth watching this forum, though, even if it's just for ideas. The Yahoo Groups might provide more model-boat-specific info than we can.

Tim B.

[mholguin]

Cool:

I'm designing (and building) an RC sailboat. I would want it to have a neutral helm (due to limitations on the equipment I'm installing), so I known (or at least I think I do) I must align the Center of Effort (CE) of the sailpland with the Center of Lateral Resistance (CLR) of the hull.

Is fairly simple to estimate the CLR, particulary on a model yacht, but how can I do the same for the CE? I'm trying to avoid having to perform a whole bunch of calculations to find it, and I really wanna have some idea on where the CE might be as to reinforce the hull... Am I making a storm in a glass of water?

Any ideas?

If you have triangular sails it's easy to find the geometric CE: just draw a line from each corner to the halfway point of the side opposite it.Where the lines intersect is the geo CE. If you have two sails draw a line between the two points.If the jib is 40% of total sail area make a mark on the line 40% from the main CE and you have the rig geometric CE.
If you have a wide hull with a long keel like the EC 12 you will want the geo CE about 8-12% of the waterline length ahead of the geo CLR; if you have a narrow boat with high aspect sails and keel fin, like a Marblehead, you want-maybe- a 1-2% "lead". On a boat like a Marblehead you can-for all practical purposes-figure the CLR at the quarter chord point of the fin. On a long keel boat like an EC 12 you can draw the underbody on a piece of stiff cardboard, cut it out and balance it on a knife edge or scale ruler with the edge at 90°to the waterline. The balance point is the geo CLR. Include the rudder area on the long keel EC 12 type; don't include the rudder area on the Marblehead type.
If your sails have significant roach you may want to factor that roach in..
There are many good books available including Steve Killing's "Yacht Design Explained" and "Larsson and Eliason's Princibles of Yacht Design" .
There are two rc forum sites Windpower and rcsailing.net ; you can get alot of info at: http://www.amya.org
Feel free to post any questions here; someone will surely help you...
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It would be a good idea if you went back and edited the title of your first post to say:"RC Sailboat Question" so people just scanning would know the topic...