The popular BONNIE-20 electric ARF, distributed by Hobby Lobby International, has been the subject of two preceding articles in Sport Aviator. The first article was on the BONNIE itself from an assembly and flying viewpoint. You can find that very detailed article, “BONNIE-20 Electric Trainer”, in Sport Aviator’s “On The Flight Line” Section.

A second article, “BONNIE-20, Adapting To Li-Poly Batteries” examined in detail substituting several of the new Li-Poly battery packs and provided the improved performance data obtained using these batteries. This third BONNIE-20 article takes up the subject of flying the BONNIE-20 off water using a pair of scale like twin floats.

Photo 1

The floats selected, like the BONNIE itself, are available from Hobby Lobby International.  These “ZEEDO”, ready to use fiberglass floats, are available in four different sizes (27 inch float length, 31, 35 and 39 inches). The four float sizes are intended for model weights ranging from 3 to 15 pounds. The particular floats chosen for the BONNIE-20 are 31 inches in length and are capable of supporting models from 5 to 7.9 pounds. While great for electric-powered models, these floats are also designed to support glow or gasoline powered aircraft.

Photo 2

Since my BONNIE weighed exactly 4 pounds (or 64 ounces) with the floats installed, the 31 in. floats were a little more than was actually necessary. But where float models are concerned, it is better to be on the conservative side and get plenty of “lift.” Keep in mind that this series of floats can be adapted to many different model aircraft; they aren’t exclusively for the BONNIE-20.

These ZEEDO floats are made from fiberglass and come in an all-white color. The combined weight of the twin floats, the mounting brackets and screws and a front wire strut, comes to a little over 9.3 ounces. Removing the three wheels from the BONNIE saved 1.5 ounces. So the net increase when substituting floats for the wheels was 7.8 ounces. The BONNIE-20 was configured with an FMA/KOKAM 3S1P Li-Poly battery pack made up of 2.0 aH/15C load capable cells weighing 6.0 ounces.

Photo 3

The BONNIE with that battery pack and wheels weighs 56.2 ounces (19.1 oz/sq.ft wing loading).The BONNIE with the same battery pack, but with floats instead of the wheels, weighs 64.0 ounces (21.8 oz/sq.ft wing loading). I think it safe to say that the weight increase was minimal and as a result the performance difference (wheels vs. floats) was insignificant.

 
Photo 4    Photo 5

The ZEEDO floats are provided with four molded plastic (or nylon) mounting brackets and sheet metal type screws. Two of these mounting brackets attach to the top of each float. One bracket is for the aft mounting point (photo 4) while the other is for the forward mounting point. The single page instruction sheet supplied is not particularly helpful. The forward mounting strut is not provided, since it will vary considerably depending on your particular model aircraft. So it is your responsibility to select, bend up and assemble this forward float-mounting strut (photo 5).