Frequently Asked Questions with Answers!
- Never use wood props - water eats wood props
- If you must add weight to balance your plane w/floats, add it to the floats not the plane
- Most trainer type planes need 2 water rudders in wind
- Short - low floats don’t work.
- CHECK ALL GLUES & PAINTS TO SEE IF THEY MELT FOAM
- Use latex paint on Electric's only!
- Use Polyurethane paint on glow!
- NEVER USE SPRAY PAINT!
Q: What length floats should I use for my airplane?
A: Normally floats can range from 75-80% the length of the fuselage, 100% for a single float. The shorter the float the less weight (and drag) you have to carry around, but you will loose some pitch stability on the water and will risk an easier flip over. A good rule of thumb is to ensure the floats extend 2-3” beyond your prop and the float step is just behind your aircrafts Center of Gravity (CG).
A: An alternate way the measure is take the distance between the prop and the CG add 2-3 inches and double it, this is a good formula for planes with a long fuselage, like the U-CAN-DO which makes a great float plane.
Q: Where should I mount the floats on my airplane?
A: Place the step a 3/4" - 1" or 2% of the float length, behind your CG, and when the aircraft is floating in the water ensure the rear of the floats are NOT submerged, If they are you may need a longer set. Make sure your hard point mountings are stiff and reliable. The floats must also have slight 2-3 degree positive angle of attack to the top of the float. Achieved by the rear float mount being slightly shorter than the main mount. If you don't have any positive incidence you will not leave the water or jump up all of a sudden sending you straight up into a stall.
(*If the step is in front of the CG the plane will porpoise when landing.)
Q: Will flying with floats affect my airplane?
A: Floats add both weight and drag to your aircraft, which will require more power and speed to maintain flight (another reason why lightweight floats are essential). Floats add a low CG the lower CG will also help to stabilize the aircraft. Float flying with your aircraft should only be attempted after you have mastered wheeled flight with the aircraft. “If the plane barely gets off the ground it may never get off the water.”
Q: What about taking off and landing a float plane?
A: Have a recovery method ready be it a boat, r/c boat, fishing pole, never swim after a plane without a life jacket. Master wheeled flight and perfect landings with your aircraft before attaching floats ..it is much more challenging.
~ Taking Off: Always take off into the wind. Advance the throttle slowly. Slight up elevator will help keep your float noses out of the water as you build up speed and the aircraft rotates onto step. Once the aircraft is "on step" and accelerating pull back on the stick and break free from the water -- again be careful to keep the nose level immediately after breaking free from the water. “Altitude and speed are your friends.”
~ Landing: Land into the wind. Keep it close, never to far out that you can’t judge the speed or altitude. Reduce the throttle while keeping the nose level. Allow the aircraft to sink in. You can flare the aircraft when it is very close to the water, but be sure you have the correct power setting to flare and the aircraft does not suddenly gain altitude when you pull the nose back and enter the flare. Once you touch down keep up elevator to keep your float noses out of the water as the aircraft slows to a stop. Practice makes perfect. Good luck!
Q: If I crash in the water is it going to hurt my plane?
A: Keeping your electronics as safe as possible from a flip-over or nose-in is important. Consider getting some water protection around your receiver, speed controls and other sensitive electronics. Also consider moving them to a point in your airframe that would be safely above the waterline should the aircraft flip over. Electric motors don’t mind too much being waterlogged but be sure to blow dry all your electronics after a tip-over (an air compressor and hot sun work great) before turning them back on. CRC 2-26 is a electronic cleaner lube spray safe for plastics that works well for cleaning contacts preventing oxidation, good for connections on all planes. (Available at Home Depot)
Q: Should I do anything different to my plane?
A: It is a good idea to attach a safety cable to the engine and around a hard point midpoint in the fuselage, this will keep your engine from sinking to the bottom if you nose in. Planes tend to stop, engines keep going! A vinyl covered fishing leader works good for this.
Q: What is the best glue to use with foam?
A: For sheeting use a foam safe spray glue, water base contact cement, for the plywood spine & top plates use a Polyurethane glue like Gorilla glue. Buy the smallest bottle you can, it has a short shelf life once opened, high humidity sets it off.
Q: If I want to design my own floats what do you recommend?
A: Use what I used when I started, an article by the late Chuck Cunningham. This is the "Float Flying Bible" newbee's read this.
Click the seaplane and it will take you to his article.