Sea Lion (oz5786)

About this Plan

Sea Lion. Free flight seaplane model.

Direct submission to Outerzone.

Update 22/4/2025: Added article, thanks to DPlumpe.

Quote: "THIS novel little flying boat will give you many thrilling hours of pleasure. We do not believe there is any finer sport than flying a model from the water. One thing one must bear in mind when launching his model from the water is that it is more difficult than land plane flying. Model built from the plans presented here may be had by enlarging the plans four times over the size shown. This may be accomplished with an ordinary pair of dividers.

Color scheme: Fuselage and hull, dark gray. Upper side of wing panel, United States Navy yellow. Lower side, silver. Elevator and rudder, gray. United States insignia used throughout.

Construction: In building the hull, 1/8-inch balsa sheet is used for the main rib. To this is attached the various formers. The builder will find this type of construction fairly simple as well as possessing a great deal of strength. After all the formers and nose plug are cemented into position, the stringers are next attached. Please note that the stringers are cemented on top edges of formers with no notches in formers. This accounts for the smooth papering job shown in finished photo of the model. Two trap doors are built into the hull for ignition purposes.

The cabane section is next built into the hull. See that this is strongly reinforced as e great deal of strength is absorbed at this junction.

In constructing the wing, build the left and right wing panel separate and cement together at center ribs after they have been finished to form the proper dihedral angle. All ribs are cut from strong 1/16-inch sheet balsa. Shape and sand leading and trailing edges carefully before they are cemented to the ribs. One-eighth inch sheet balsa wing tips are used throughout. A few 1/8-inch square balsa diagonal compression struts may be cemented into the wing panel to add further to their strength. These, of course, are not shown on the plan and may be added if so desired. Note: center of wing carries the firewall and motor mount. See that these are cemented in strongly.

Construction cif the elevator and rudders are of the flat section and all very simple to construct. It is very important that these be pinned to a flat surface when shrinking as they have a tendency to warp out of shape.

Details such as installation of motor, batteries, coil, etc, are clearly shown on the plan. Please note that the only batteries necessary are two small flash light pen cells. These are bound together with Scotch cellulose mending tape. The wire sections are held in place with this same tape. After the model has been completely finished, these batteries are tapped within the hull at the proper balancing point.

In covering the model, n great deal of time should be taken as this will be a vital factor in the success of the model. Many a fine model has lost its excellent workmanship by a poor covering job. In covering the hull, we advise the builder to cover only one to two stringer spaces at a time. By this we mean not the entire length of hull. The bottom of hull should be covered with two layers of bamboo paper in order to obtain the required toughness. In papering the bottom, shrink with water, allow to dry and give two coats of dear dope with a light sanding between each coat. Apply a second layer of bamboo paper, then repeat the procedure.

In covering the wings, each panel may be covered with a single sheet with the exception of the last rib to the wing tips. Make sure bamboo paper is cemented to every rib on the bottom side so as to gain the efficiency of the cambered section. Sponsons should be built and placed in exactly the same position as shown on plans. These are also covered with two layers of bamboo paper on the bottom sides. All parts are shrunk by applying a light coat of water. Allow this to dry until paper becomes taut. Two to three coats of clear dope are next applied. For a smooth finish give a light sanding between each coat.

Colors are next applied, as well as all details shown in the plan. Aluminum tabs on the wing and rudders will give lateral and directional control. Make sure model glides, on an even keel, gently to the ground before attempting to launch it. Keep all wires covered with a thin coat of wax and framework of hull should be varnished or doped before covering.

Any removable hatches should be sealed up tight with Scotch cellulose mending tape so as to prevent water coming in contact with the wiring and batteries. This tape is easily removed when checking and installing new batteries and also is waterproof. This mending tape may be secured from any dime store, drug or hardware store. Make sure that it is genuine Scotch cellulose mending tape, as other substitutes will not work.

If the finished model does not balance properly, weight may be added to nose through the front hatch. Be careful in launching the model from the water. Head model directly into the wind and attempt only short hops at the beginning."

Supplementary file notes

Article.

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