I've got a set of SeaCommander 48" floats for my 108" WS Piper SuperCub.
Also picked up the SeaCommander mounting system.

Now, how do I figure out how to set the floats up?

Incidence: Most published articles and certainly full scale cubs have the wings 3-4 degrees positive to the top surface of the floats. Some find that with flat-bottom airfoils the bottom surface of the wing can be parallel to the top of the floats. Positive incidence has always worked better for me.


How far apart? ( center line to center line )
25% of the wingspan is a guideline

How high? ( top of float to bottom of plane )
The bottom of the prop arc to the plane of the top of the floats should be about 15-20% of prop diameter.

Where to set the step in relation to the CG? ( fore or aft )
The step goes essentially under the CG (Balance point). Many published articles put the step slightly behind the balance point. One article says it should be under a point at 40% of the MAC (which is the same as the wing chord on a cub). ANother article shows it at 10 degrees behind the balance point....which is about the same place. THese are starting points and some flyers report good results with the step slightly ahead of the balance point. 40% has always worked for me.

Spray Rails? ( yes or no )
Try it without. Be sure to use a plastic prop anyway. DO NOT use a wood prop. Spray will splinter it.

What is the best set up for tensioning rods? ( mounts and hardware needed )
From the upper front strut to the lower rear strut. The float mounting should be rigid.
Search the internet for Brown's seaplane base. There are scads of photos of full-scale cubs so you can model how they do it

Water rudders? ( what works best )
ERNST water rudders are scale-like and retractable. Hard to beat. Get the big ones.


Attaching the mounting system to the plane? ( streamline tubing to what? )
You'll have to attach flat plates into the ends of your streamline tubing. They attach to the landing gear mounts of the plane. You'll have to add a hard point to the floor in the aft of the cabin for the rear struts. There was another thread yesterday where a guy attached scale fiberglass floats to a cessna model with streamline tubing. The pictures will help you.