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Chapter 10 - Model Seaplane Flying

Virtually all model aircraft can be fitted with floats for flying from water sites, or with skis for operation over snow-covered areas. This type of flying presents a refreshing departure from take-offs and landings on dry ground and affords a thrilling new experience for the model-airplane enthusiast.

Water-based aircraft can be divided into three classifications: "flying boats", the fuselage of which is shaped like a ship's hull; "single-float seaplanes", with one main float supporting the fuselage and utilizing small floats at the wing tips to obtain stability on the water; and the most popular of all, "twin floats." All three types can be successfully operated in model form; however, in view of the fact that most models are built as land planes and are later converted into seaplanes, we recommend and shall describe "twin floats." This type can be readily installed on any land plane, although some full-scale aircraft are not easily fitted with seaplane gear. Since this is a volume on scale models, we will describe the installation for the "Aeronca Sedan", "Northrop Gamma", and "Curtiss Goshawk" only because it is known that these full-size craft can be fitted with floats.

Elying Models Photo

Many speedy flights were made with this sleek "Supermarine S6-B" racer. Powered by a .49 engine, this thirty inch span model attained seventy-five miles per hour. Landings required some skill. This type of craft is not recommended for the novice but the expert can really enjoy himself with the challenge it presents. It will be noted that the floats are of a different design than we describe.

Our floats are patterned along the lines of standard commercial types and are carved from solid balsa blocks in the manner previously described for fuselages. The floats are, however, divided along the vertical centerline in lieu of the horizontal. Once separated, these can be hollowed as the plans illustrate; the interior should receive several coats of dope in order to insure watertightness. Thick coats are recommended.

Saw the plywood bulkheads to shape and carefully fit into the float sides, cutting here and there to insure a good fit. Drill holes into the plywood and then cut the aluminum sheet straps.  These are bent around the brass tubing.   Now, bend the 1/16" music-wire crossbraces as shown; these are inserted into the straps and the straps are then bolted to the plywood, holding both the tubing and crossbraces in place. Cut away part of the float to make room for the tubing. This tubing must protrude above the float upper surface. Securely cement the two bulkheads into the inboard float upper surface. Securely cement the two bulkheads into the inboard float halves, then apply plenty of cement to the remaining outboard float halves and join under pressure. Do not disturb for at least four hours, preferably overnight. The balsa cross-brace fairing is optional.

"The  Lensman"   Photo

These floats are replicasof standard commercial designs and will be in good taste on any scale model. They are permanently attached to each other via the two wire cross braces. The forward brace is faired by a sheet balsa streamline as is customary on most fuel scale floats. The permanent attachment of these floats aids considerably in installation and alignment. Distance between floats should be equal to one-half the length of the float.

The importance of the external finish cannot be overemphasized. Apply at least six coats of sanding sealer and follow with five coats of fuel proof silver dope.

Installation is as noted on the plans. Although this varies slightly with each plane, the principle is the same.

Model Airplane News Photo

The single float design is typified by the author's model of "Admiral Byrd's Loening Amphibian". This particular craft could land on water or earth by merely adjusting the landing gear. Note the wing tip floats which keep the model upright on the water.

Rubber bands hold the wheel axle to the tubing, while an additional music wire strut is bent to fit the rear float connections. This rear strut is firmly attached to the model in the same manner as the conventional landing gear or held in place with rubber bands.

The position of the "step" is most important. This should be directly below the balance line of the model for quick take-offs and safe landings. The floats should also be tilted upward toward the nose, as the plans make clear.

All water flying should be done from a pond or lake no deeper than 18 inches. Deeper water would hinder any necessary footwork required during the flight. Do not fly while standing in a boat, for an accident and crack-up may result. Stainless steel or enameled lines should be used. Trial flights should be made with lines not over 40 feet in length.

Model  Airplane News  Photo

Skiplanes are much fun and it does not require a great deal of work to attach these skis. This replica of "Lincoln Ellsworth's Polar Star Northrop Gama" is very similar to the model described in chapter five. Note the rubber bands that hold the skis at the proper angle during flight in order that the rear of the ski will touch the snow or ice first.

The engine is usually started on shore and the craft is then moved into the water for take-off. Before the model is released by the helper, the flyer should be certain that the lines are out of the water. If the lines are in the water, they will cause the craft to turn in towards the "pilot." The model should be launched pointed slightly away from the circle center and the flyer should "lead" the plane slightly to prevent the inboard float from dipping into the water. This is often caused by the engine torque, but only when the craft is traveling slowly during take-off. Acceleration is considerably slower than with landplanes.

The plane will invariably rise on the step by itself; then it requires only is a very slight "up" elevator to break the surface suction and become airborne. Landings may require a slight amount of leading. This depends on the wing loading of the model. When the craft approaches the water, apply slight "up" elevator to cause that portion of the float just forward of the step to touch the water first.

It is advisable to use a propeller approximately ten percent, smaller in diameter on seaplanes than would normally be used on a land plane. This is done in order to keep the propeller blade out of the water spray. Should the model turn over and the engine become submerged, it should be run at once after being drained and cleaned with alcohol or fuel. Flight lines should be wiped with an oily rag before they are wound up at the end of a flying day.

Aeromodeller Photo

The floats used on this scale model of "Charles Lindbergh's Lockheed Sirius" are identical in design to those presented in this chapter. Scores of water flights and even some flights from moist grass were made with this craft. Step should be under the center of balance for quick take off.

"The Lensman"   Photo

The author's "Bellanca Pacemaker" is shown "riding high" on the twin floats described in this chapter. This design of float is very buoyant and can support models of the heaviest wing loading. This is very important when it comes to take offs because if the float is deep in the water, the take off run will be quite long and will require considerable power.

"Target" Photo

Flying boats are another interesting phase of this hobby that is open to the experienced modeller. This photo shows the author flying his "Consolidated PBY Catalina" from land. The wheels are detachable for water flying. Models of this type make excellent beauty entries. This "Cat" sported pre-war Navy paint job.

Skis can be fitted much more easily onto model airplanes than floats. These are generally made from hard wood, plywood, or sheet plastic It will be noted that the axle slides through the ski pylon and that rubber bands hold the ski at an angle of from ten to fifteen degrees to the airstream. Flying ski planes is no different than wheel-equipped models. Select ice or fresh fallen snow as the flying site. No ski is required for tail-wheel models, but tail skids should have a ski added.

Whether it be on snow, ice, or water, much enjoyment is yours with these unusual mediums from which to operate your favorite scale-model airplanes.

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