Tips For Adding Floats To Your Airplane
Recently a PropBuster member asked me what might be a good first float plane for upcoming club float flys. My response was simple, "Put some floats on your first high-wing trainer and you'll be ready to go!" High wing airplanes make great float planes.
When selecting floats for your plane, measure the fuselage from the prop to the hinge line of the rudder; the length of the float should be at least 75% of this distance. Place the step of the float exactly below the balance point of your airplane. I have been told you can have the step up to 1/2 inch behind the CG, but never in front of the CG.
The CG should be in exactly the same place when flying off water as it is when you fly your airplane off land. You may have to add a bit of weight to the nose to make up for the weight of your missing landing gear. Don't omit this step in preparing your plane to fly off water!!
Always use a nylon prop when flying off water. A wood prop will be chewed up quickly when water spray from the floats gets kicked up into the propeller.
A water rudder will help greatly in maneuvering your plane on the water. You can attach a rudder to the aft end of one of the floats, or attach a small water rudder to the aircraft rudder. The water rudder should be set so it is immersed in the water at taxi speed, but clear of the water when the model is up on step at take off speed.
2 degrees of positive incidence between the top line of the floats and the wing chord line will help the aircraft lift off the water on the take off run. Without the positive incidence your plane may end up being a motorboat as it taxis around the lake!
Good float kits are made by Goldberg and Great Planes. Prefabricated floats are available from Sig, Just Plane Floats, and Maxford. Ernst Manufacturing Co. produces two different sizes of water rudders that work very well. I am sure there are many other sources out there for your float flying needs if you look.
We will be flying off water at Trap Lake in the Shelby Farms Park the first Saturday of each month starting in April from 9:00 - 12:00 noon. If I can be of any assistance to you as you approach this exciting aspect of our RC hobby, don't hesitate to call me. I hope to see you at the lake!