RC Airplane World - Complete Beginners RC Flying Guide

RC Floatplanes

- Rise to the Challenge of Flying from Water!

If you have access to a lake or wide and slow-flowing river, rc floatplanes and seaplanes can give you a more challenging and very rewarding radio control flying experience.

There aren't a huge number of Ready To Fly floatplanes widely available at the current time, but there are RTF options available. An increasing number of manufacturers of RTF foamie rc planes give you the option of swapping out the normal landing gear for a set of specially designed floats.

As an example, the photo below shows my little UMX Timber sitting pretty on her floats:

E-flite UMX Timber on floats

Such floats, called pontoon floats, are made from lightweight foam, typically with pre-bent wire struts that slot straight into the landing gear slots on the underside of the fuselage.

Floatplane or Seaplane?

An alternative configuration to the pontoon floats is the single hull aircraft, commonly called a seaplane or flying boat.

These are usually larger than planes equipped with pontoon floats, and a very popular subject for radio control is the Consolidated PBY Catalina, pictured below.
This particular example is the Great Planes ARF example:

A Catalina is a popular rc seaplane

RC Floatplanes: Take off & Landing

The primary difference between rc floatplanes (& seaplanes) and land planes comes in the amount of drag they encounter.

On take off, rc land planes encounter very little drag when rolling along a smooth runway. But rc floatplanes encounter lots of drag as the floats try and cut their way through the water surface tension.

The amount of drag is relatively huge, until speed is sufficient that the floats start to ride on the surface of the water and the airplane 'planes' across the surface until it gets airborne. During the planing stage of the take off, the amount of drag is reduced significantly.

The same obviously goes for seaplanes. When the bulk of the hull is in the water there is excessive drag, which lessens considerably as the hull accelerates and eventually planes on the surface.

Like land planes, an rc floatplane should be taken off in to wind whenever possible. If there is significant chop on the surface, you might need to do your take off run parallel with the line of waves, and this probably means doing a crosswind take off.

The trick is to hold in more up elevator during the take off run than you would do when taking off from land; this holds the nose of the airplane up and helps prevent the floats from digging in to the water.
As the speed increases, you should be able to reduce up elevator slightly and let the plane ride the waves, so to speak. Once take off speed is reached, let the plane lift gently off the water with a small amount of up elevator, and maintain a smooth and gentle climb out from the lake.

A bad rc floatplane landingLanding an rc floatplane or seaplane on water isn't something you want to get wrong, unless you want to end up like this poor guy to the right.

The same can be said for landing - try and land parallel to any chop to prevent the front of the floats digging in and flipping the plane.

Landing an RC floatplane

Above: you should try and land parallel to any wave troughs.

I've learned the hard and embarrassing way, and my first attempt at floatplane flying ended before it began when my plane flipped onto its back after digging in.

Obviously if there is little or no chop on the water then you can land in to wind, if possible. Only a larger amount of chop needs to be taken into account when landing. Or, more accurately, the size of the chop relative to the size of plane needs to be observed!

When landing an rc floatplane, you should come in as slowly as possible and flare as much as possible so that the floats touch the water as gently as possible. The plane should have a relatively high nose-up attitude as it touches down.
If your plane is equipped with flaps, use them to really slow the plane down on approach.

Importantly, you need to get good at landing on dry land before you head for the lake. If your land-landings aren't yet as smooth and bounce-free as they could be, put in some more practice.

Another point to make is that it's a good idea to have some kind of plane-retrieval system in place, should your floatplane find itself stranded in the middle of the lake!
A radio control boat is ideal for this purpose, or a friend with a real boat.

Taxying Trouble

Despite the increased drag of the floats or hull in the water, floatplanes can be very much affected by a breeze, even a slight one.
This is largely because there is little to stop the plane being blown around on the water surface, rather like a ping-pong ball would get blown around.

Obviously the heavier the plane, the less it will be blown around, but something ultra-lightweight is going to suffer until you get it on its take off run and its speed up.
If your plane's floats don't have a small rudder fitted to them (most don't...) then getting control authority from the plane's main rudder is a priority. Of course, this will only happen with increased speed and airflow over the fin.

So be prepared for your little floatplane not to always do what's it's told when you're taxying it on the water!

Water Area Size

How much water you need is obviously going to depend on the size of your floatplane - larger planes are going to need longer take off runs.

For something smaller, such as my little UMX Timber shown at the top of this page, I can get away with a surprisingly small area of water to take off and land from.
Shown below is a local stream that I've flown it from before; on the occasion I took this photo the water surface was like a mirror, and there wasn't a breath of wind - perfect floatplane flying conditions!

Perfect water for the Timber

RC floatplanes and seaplanes are a lot of fun, and if you have easy access to a lake or good size pond then take advantage of it and have some fun!
Just practice those landings on land and get them perfect before you attempt any water landings!

Below is a nice video of some rc floatplane action, just to 'wet' your appetite...

 

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