Pelican (oz2169)

About this Plan

Pelican. Free flight seaplane by Ken Willard.

Quote: "By Ken Willard. Remember the Drake? Its designer does even better with this amphibian for Half A power. Features all-balsa construction and tail tip floats to avoid digging in on water.

Every time you design and build a model amphibian, you get another idea which you hope to incorporate in your next model. Some of the ideas are good; some are bad. The net result should be a better model with each succeeding design. The many MAN readers who built the Drake (oz1251) will be interested in the Pelican, a model amphibian which was designed to fulfill several purposes!

(A) It is all balsa. This eliminates not only the covering job. but also the possibility of having holes punctured in the surfaces, which would allow water to get inside. The sheet balsa wing and tail give very satisfactory flight characteristics; however, some modelers will probably decide to make built-up wings and tail, It is probably true that by modifying the Pelican in this way, slightly better performance will result; however, the writer was looking for simplicity.

(B) One of the difficulties with an amphibian when flying off the water is the tendency to have spiral instability, caused by either a wingtip pontoon or a sea wing on one side dipping into the water, creating drag on that side and causing the model to proceed in a tight circle horn which it cannot break loose and subsequently take off. In an attempt to eliminate this, the Pelican has a modified planing hull type of bottom. When the hull sides are bent together to meet at the tall, there is a slight downward bend which is due to the slant in the sides. This gives a slightly concave line to the rear planing area, and the model planes on the step and the rear of the hull. Since the rear of the hull comes to a point and a portion of the rudder is still in the water, this gives good water directional characteristics. The location of the pontoons on the tips of the stabilizers is somewhat of a novelty. They are not flotation surfaces as is the case with contest models, where the model sit on the front float and the two rear floats. The pontoons on the Peilican are for water stability only. Except in a crosswind, the Pelican floats level with the pontoons out of the water. On take-off, if one wing drops and a pontoon drags, its location at the rear reduces the tendency to pull the model into a tight circle. Only a slightly curved path results, and the model gains enough forward speed to level off and break the dragging pontoon free. Also, when flying the Pelican as a land plane, the pontoons are out of danger in rough landings.

(C) Since the Pelican is amphibious, it has to be able to take rough landings on land with a minimum of damage. For that reason the wing and tail are mounted with rubber bands, which allows them to break away from the hull without doing any damage in the event of a rough landing.

By studying the plans and looking at the photos you will be able to complete most of the construction without difficulty, However, since the model is simple enough for the modeler just out of the beginner stage, step by step construction procedure is presented. Also, for the modeler who is not too familiar with materials, the detailed bill of materials will assist in obtaining the proper grade of wood for each part. With the full size plans, the bill of materials, and the building instructions, you should have no difficulty in building the Pelican over a couple of weekends in your spare time.

Because of the high camber to the sheet balsa wing, the Pelican is not too sensitive as to its balance point, If you get the balance point about 40 to 45 percent back from the leading edge of the wing, you can make any necessary adjustments by adding weight to the nose or the tail, and subsequently by shimming up the leading edge of the stabilizer if the model has a stalling tead.ency, or shimming up the trailing edge of the stabilizer if there is a slight diving tendency.

The model should balance pretty close to the desired point with the landing gear attached. When the landing gear is removed for flying off the water, some weight in the nose will be required to compensate for the weight of the removed gear. Modeling clay is the usual material. The writer used a length of 1 /4 rubber tubing filled with strip solder and screwed into the nose block to look like a bumper.

Because the model is not greatly overpowered, it is not too sensitive as to its flight path. However, in order to keep the model from flying too far away, a flight path in a large left circle is recommended. This keeps the ship within range, yet it does not impair the take-off characteristic"

Supplementary file notes

Article pages, text and pics, thanks to theshadow.

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