BACKGROUND ART A model plane is comprised of an airframe having a fuselage and wings, and an engine, and is controlled to take off, land, and fly by means of a remote controller.

When the model plane takes off, lands, and flies, the engine produces a thrust allowing the model plane to go forward, and a lift allowing the model plane to move upward. At this time, a drag such as an air resistance reacts upon the thrust, and gravity reacts upon the lift.

In order to reduce a weight of the model plane, the fuselage and wings are made of a material such as a balsam fir, plastics, or the like. Particularly, in the case that the fuselage and wings are made of the balsam fir, a board of the balsam fir should be coated with epoxy resins, a printing film, and a polyester film in sequence, and then

should be solidified by a thermocompression bonding. As necessary, the balsam fir may be coated with fiberglass, a carbon fiber, or the like for increasing the durability of the balsam fir.

However, in the conventional model plane made of the balsam fir, the plastics, or the like, manufacturing of components becomes difficult, so that not only a design of the model plane is restricted but also time required to assemble the model plane is prolonged. Moreover, it is difficult to preserve the model plane because the model plane is likely to break down by an outside impact.

Further, in the case that the model plane is made of the balsam fir, it is difficult to purchase the balsam fir DISCLOSURE OF INVENTION Accordingly, the present invention has been made keeping in mind the above-described shortcomings and user's need, and an object of the present invention is to provide an airframe for a model plane and a model plane using the same, in which it is easy to purchase a material thereof, the durability thereof is improved, the weight thereof is light, components manufacturing becomes easy, time required to assemble the model plane is shortened, and a mass-production is possible.

This and other objects of the present invention may be accomplished by the provision of an airframe for a model

plane comprising a fuselage and wings, further comprising a bony frame formed by combination of a plurality of pipes forming at least one of the fuselage and the wings, and a skin surrounding the bony frame.

Here, the pipe is made of aluminum or aluminum alloy, so that durability is improved, a weight is lightened, and components manufacturing becomes easy.

Preferably, the skin is made of a cloth, and at least one side thereof is waterproofed Desirably, the airframe a grained timber is adhered to the skin.

Further, joints connect the plurality of pipes to each other, so that a weight is lightened and time required to assemble the model plane is shortened.

According to another aspect of the present invention, the above and other objects may be also achieved by the provision of a model plane comprising an airframe having a fuselage and wings, and an engine, the airframe further comprising a bony frame formed by combination of a plurality of pipes forming at least one of the fuselage and the wings, and a skin surrounding the bony frame.

Here, the pipe is made of aluminum or aluminum alloy, so that durability is improved, a weight is lightened, and components manufacturing becomes easy.

Preferably, the skin is made of a cloth, and at least

one side thereof is waterproofed Desirably, the airframe a grained timber is adhered to the skin.

Further, joints connect the plurality of pipes to each other, so that a weight is lightened and time required to assemble the model plane is shortened.

BRIEF DESCRIPTION OF DRAWINGS The present invention will be better understood and its various objects and advantages will be more fully appreciated from the following description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a schematic perspective view of a model plane according to the present invention; Fig. 2 is a sectional view of a main wing taken along line II-II in Fig. 1 ; Fig. 3 is a sectional view of a fuselage taken along line III-III in Fig. 1 ; Figs. 4a-4e are detailed views of joints; and Fig. 5 is a partial perspective view of a pipe combined with a skin.

MODES FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

Fig. 1 is a schematic perspective view of a model

plane according to the present invention. As shown therein, the model plane comprises an airframe 10 and an engine 12, and the airframe 10 includes a fuselage 20 and wings 30.

The wings 30 include main wings 32 laterally provided at the middle of the fuselage 20 and generating a lift, a horizontal stabilizer 36 laterally provided at the tail of the fuselage 20 for vertically stabilizing, and a fin 38 upwardly provided at the tail of the fuselage 20 for left and right stabilizing.

At a front end part of the fuselage 20 is provided a propeller 14, and the propeller 14 is connected to. the engine 12 and rotated by the engine 12, thereby producing a thrust allowing the model plane to go forward.

At a front upper part of the fuselage 20 is provided the engine 12, and the engine 12 receives a fuel from a fuel tank (not shown) and generates power, thereby rotating the propeller 14 connected thereto.

At a lower part of the fuselage 20 is provided a landing gears 16 each having a leg and a wheel, supporting the model plane.

Here, reference numbers 24 and 34 of Fig. 1 respectively indicate bony frames of the fuselage 20 and the main wings 32 according to the present invention, and those will be described later in more detail.

In Fig. 1, only a bony frame of the main wings 32 is

shown, but it is desirable that the other wings 36 and 38 are comprised in the same manner as in the bony frame of the main wings 32. As shown in Fig. 2, each of the main wings 32 is comprised of the bony frame 34. The bony frame 34 includes a plurality of pipes 50 made of aluminum or aluminum alloy, which are connected to each other along the edge of the main wings 32 in order to form a outer appearance of the main wings 32, and connected to each other with a lattice shape inside the outer frame in order to reinforce the outer frame. Lengths of the pipes 50 are different each other according to connecting positions thereof, and it is desirable that the lengths of the pipes 50 are previously standardized.

The main wing frame 34 is surrounded by a skin 60 and forms an external appearance of the main wings 32. The skin 60 is made of a cloth, and the cloth is waterproofed with epoxy resins.

In Fig. 2, reference numbers 55 and 60a respectively indicate joints connecting the pipes 50 each other and ring parts provided at the rear of the skin 60, and those will be described later in more detail.

As shown in Fig. 3, the fuselage 20 is of a streamline shape, and comprised of fuselage frames 24. The fuselage frame 24 includes a plurality of pipes 50 made of aluminum or aluminum alloy, which are connected to each other along

the edge of the fuselage 20 in order to form an outer frame of the fuselage 20, and connected to each other with a lattice shape inside the outer frame in order to reinforce the outer frame. Further, it is desirable that the lengths of the pipes 50 for the fuselage 20 are previously standardized like those of the pipes 50 for the main wing 32.

The fuselage frame 24 is surrounded by a skin 60 and forms an external appearance of the fuselage 20 like that of the main wings 32. The skin 60 is made of a cloth, and the cloth is waterproofed with epoxy resins. Here, the reference number 60a indicates a ring part provided at the rear of the skin 60.

As shown in Figs. 4a-4e, a reference number 55 indicates joints connecting the pipes 50 to each other.

The joint 55 is of a hollow structure, and connects the pipes 50 to each other according to the mutual connections of the pipes 50 with I-, T-, cross-, L-shapes, etc.

Further, a combining part 55a of the joint 55 has an outer diameter approximately equal to an inner diameter of the pipe 50. On the other hand, the combining part 55a of the joint 55 may have the inner diameter approximately equal to the outer diameter of the pipe 50 so that the pipe 50 is inserted into the inside of the combining part 55a of the joint 55, which is not shown herein.

Fig. 5 is a partial perspective view of the pipe 50 combined with the skin 60. As shown therein, the outward pipes 50 of the fuselage frame 24 and the main wing frame 34 are inserted into the ring parts 60a provided at the rear of the skin 60, and therefore combined with the skin 60, that is, the skin 60 surrounds the outside of the fuselage frame 24 and the main wing frame 34, thereby forming an external appearance of the fuselage 20 and the main wing frame 32.

With this configuration, the pipes 50 are combined to each other by means of the joints 55 according to the connections of the pipes 50 constituting the bony frames 24 and 34 of the airframe 10, and the skin 60 surrounds the bony frames 24 and 34 of the airframe 10 by inserting the outward pipes 50 of the bony frames 24 and 34 into the ring parts 60a provided at the rear of the skin 60, thereby forming the external appearance of the airframe 10.

Here, the skin 60 is preferably made of a cotton cloth, and the outward surface thereof may be waterproofed with a urethane resins, lacquer, or varnish, instead of the epoxy resins.

To the outward surface of the skin 60 may be adhered a grained timber (not shown) instead of the waterproofing, thereby improving the durability and tidying up the external appearance.

Further, the pipes 50 constituting the bony frames 24 and 34 may be made of plastics instead of the aluminum or aluminum alloy, which is similar in quality or function to the aluminum.

As described above, a bony frame of an airframe is formed by pipes made of a material which is light and has good ductility, and the bony frame is surrounded with a waterproofed cloth, so that durability is improved, a weight is lightened, various design applications are possible due to a easy working, and a mass-production is possible.

Ad described above, the present invention provides an airframe for a model plane and a model plane using the same, in which durability is improved, a weight is lightened, components manufacturing becomes easy, time required to assemble the model plane is shortened, and a mass-production is possible.

Although the preferred embodiments of the present invention have been disclosed for illustrative purpose, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.