I have 2 profile's I want to put floats on. Both are from prop to rudder hinge line is 36". Wing span is 48". I have a set of 35" GP floats meant for my 40 size Cub. Is there a formula for this. The mounting blacks are 14" apart . HELP.

The rule of thumb is 85% of the fuselage length, prop to hinge line. That would give you a 30" float, but weight is more important than size and your planes are very light. You won't need a float even that large.

If you want to retain anything like the original performance of your airplanes, you will want to use the lightest floats you can. Go to www.geocities.com/planefunfloats and get their 27" floats.

Jim

Here are some additional links to help you with the design and installation:

http://www.foamfloats.com/

http://www.seacommander.com/seafoam.asp

http://www.seminolerc.com/floatcores.html

http://www.seminolerc.com/EZ-Float-Design.html

http://www.geistware.com/rcmodeling/...oats/index.htm

Chad

For lightweight floats I would try the 680mm Hyperion floats. You can find them [link=http://www.aircraft-world.com/shopexd.asp?id=4570]here[/link] and probably in other places.

Certainly the right length, and quite light...but I wonder about the width and thus their ability to float weights greater than the advertised 3.8lbs.

Make sure you do what is necessary to keep water from running along the pushrods and ending up in the servos. When a servo gets water in it, it freaks out. Make sure that water cannot get to the receiver or the battery switch. Spray from the floats and the prop will get into places you wouldn't believe.

The small floats recommended will work fine. Get the step either over or up to 1/4" ahead of the CG, and make the floats about 30% of the wingspan apart. Take care to get the wing incidence about 1-2 degrees positive in relation to the tops of the floats. Make the struts tall enough that the prop isn't too close to the waterline.