Simple Sunday Seaplane (oz6243)

About this Plan

Simple Sunday Seaplane . Radio control sport model. RCM #763 1979. Build is included. Designer Ken Willard 1979. Wingspan 37-1/2 in.

Quote: "Fifteen years ago (January 1964 RCM) I published a design named the Virus (oz5713). It was intended for the absolute beginner in building. All balsa, sheet wings, single surface, it was ultra simple to construct, and it also was a good flying model.

For several years, the original Virus flew as a landplane. Then I had an idea - convert it to a seaplane. So, I built up a set of twin floats and tried it. No luck. It was underpowered. I increased the power from an .020 to an .049. Still it would not take-off from the water, but it was pretty wild in the air. I modified the float design a bit; originally they were straight sided from nose block to tail block. I tapered the back end to the shape which they now have. Still no take-off - so at that point I figured there was something basically wrong and discarded the idea. But it kept haunting me through the years.

Meanwhile, with several flying boat designs working very well, I kept learning through trial and error what hull design worked best. Perhaps the most significant event was during the design phase of the Wavemaster. I had specified a step design, but the production manager for the ABS plastic version wanted to modify it to save production costs. We tried his version - it was totally unsatisfactory. Although the model would take-off from the water, it was strictly by brute force. When we went back to the specified step design, the model would take-off at half throttle.

With that experience in hand, I knew what had to be done to the floats which were originally designed for the Virus. But many things had happened to radio control in the intervening years, so a new design was in order. And, thus, the Simple Sunday Seaplane was conceived. I would use the Virus floats. with the step modified to give the right depth and upsweep to the float bottoms. Some modelers look at the Simple Sunday Seaplane and say: Hey, isn't that a bit of overkill on the float size? Nope. Y'gotta keep in mind what this design is intended for.

Another plus is that the prop is way up there above the fuselage, and doesn't pose a danger threat to the passengers. Yeah, that's right.

By now, he's convinced that a lot of thought went into the design. so there's no sense in telling him that it came about because a fifteen year old design didn't work. We'll just keep that a secret between you and me. All 120,000 of us.

For a while, it looked like I still had a problem. During the initial testing, I flew the SSS as a landplane, strapping the Halloo gear to the bottom of the fuselage with double stick tape, and with the wheels properly located just under the leading edge of the wing. Flew very well, and handled well on the ground, using the Ace throttle for low speed taxiing.

So, up to the lake for water tests. Taxied fine; the tail wheel serves double duty as a water rudder, and the model steered well, so I applied power. It came up on the step, scooted over the water, and took off. Great. After a few banks and turns, I tried a loop. Right at the top, without any help from me, it snap rolled! When it came out, with a bit of down elevator, and was headed down for the water, I applied up elevator; another snap roll! And that process repeated itself until the model snap rolled into the water.

It was only about seventy feet out so, with my trusty spinning rod, I cast a one ounce weight out and beyond the model, the line dropped on the model and, as I slowly retrieved the weight, it hung on the model and I brought it in.

While the SSS was drying out (one of the best things about crashing in the water is that damage is either slight or there isn't any), I analyzed the problem. It was two-fold; the vertical tail area was insufficient for the big side area of the floats, and the Center of Gravity was too far back. This wouldn't show up in the landplane version.

I had a couple of stick-on weights with me and I attached them to the front of the floats. You can still see them there in the photos. When the radio dried out about a half hour later (this was fresh water, of course) I fired up and tried again..."

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