I-14 B3 Rudder Shape

[smakinen]

Can someone point me in the direction of getting the specific foil geometry for the rudder, in computer file format? Or how to get a new rudder to replace the original rudder on an I-14 Bieker 3 design (USA 1134)?

If I go the route of building a rudder, then keeping the same shape would be nice so that the new one fits into the same tiller cassette. I believe that the boat has the original rudder and tiller/tiller-cassette.

This is part of a project, which will hopefully come to fruition, to make a T-foil system with non-fixed horizontal foils. My hope is to make a mold, and build a rudder with the linkage inside. Knowing the geometry of the rudder is the first step. Then I can make a female mold with a CNC router, which I can actually get access to.

Stepping back for a bit, if someone sells these rudders, let me know. I don't have to build this system myself. Even without building a T-foil system, I'd like to know of how to get a new rudder in case I do something terrible like break the existing one.

I've also inquired with I-14 email groups, just inquiring within this forum to try to get hits from other knowledgeable people.

[tspeer]

Originally Posted by smakinen

Can someone point me in the direction of getting the specific foil geometry for the rudder, in computer file format? Or how to get a new rudder to replace the original rudder on an I-14 Bieker 3 design (USA 1134)?...

You could use your existing rudder as a plug and splash a mold off of it, at least for the portion that goes into the cassette. Since you want to use a female mold anyway, that is probably the simplest way to go, and it guarantees it will match your existing rudder shape.

Perhaps you should contact Paul Bieker and ask him what section he uses for the rudder. If it's a common section shape, you can probably find the coordinates for it at the UIUC airfoil site. If it's a custom section, he'll have to provide you with the coordinates, or you'll have to measure them yourself.

Measuring the section shape from your existing rudder is another way to go, but hard to do accurately. The site that has the CNC machining may have the equipment to accurately measure the rudder shape. Or you might assume that the shape is from, say, one of the NACA airfoil families and find a section that matches up with your measurements. Then use the published coordinates for the CNC machining of the mold.