TECHNICAL FIELD

The present invention relates to models in general, and more specifically to flying model airplanes with attachments allowing positive assembly and dissembly of component parts.

BACKGROUND ART

Model airplanes have been known and in common use almost since the time that engine driven aircraft be- came a reality. Flying models have been popular and have, in the past, been fabricated of a balsa wood structure covered with fabric or thermoplastic material, hollow, or so]id expanded plastic, such as urethane foam and blovm polystyrene beads, also, flat wood, or plastic sheet, etc. , each representing either a specific air¬ craft or a derivation thereof. Flying model airplanes have also been powered by twisted rubber bands, gasoline, or electric motors, compressed gas, or rocket type thrusters in many styles and configurations, each attempting to simulate flight using the basic aero¬ dynamic principles of an original craft. Prior art has been attempting to achieve a number of different goals,

that of scales miniaturization and optimum flying qualities, regardless of appearance. The instant in¬ vention is directed to an approach that is inexpensive enough to be practical and, yet, have sufficient struc- tural integrity to function efficiently with enough shape to allow detail to be illustrated projecting the feel and general appearance of the original aircraft. Further, the invention allows easily removable struc¬ tural joining of component parts heretofore unavailable in the combination thus disclosed.

DISCLOSURE OF THE INVENTION

Since model airplanes powered by rubber bands or direct current electric motors must, by their very nature, be extremely light and fragile, the problem of assembly and disse bly has plagued model builders. It is, therefore, the primary object of the invention to provide a model that is fabricated of a thin foam thermc- set material with junctions to the major components so interrelated that only two connections need to be made to assemble or dissemble all of the major elements. This is accomplished by mating the wing to the fuselage and inserting the landing gear into an eye that is directed through a reinforced interlocking member in the wing tieing all three members securely together. The tail is similarly joined with the elevator juxtapositionec on the top of the fuselage and the vertical stabilizer having a projecting finger interface with an inverted dovetail on the body. Again, three elements are connect¬ ed together using an integral reinforced joint.

An important object of the invention uses a triangular fuselage with two sides bonded together and a separate bottom inserted between the sides creating a strong body that not only has integrity of stiffness, but also gives depth to the thin material. Further,

the triangular shape is slightly below the top outline of the fuselage allowing the cockpit area to extend above, giving further appearance of width relationship simulating the actual aircraft structure. Another object of this triangular shape lends the model to have the details printed or silk screened on the outside surface of each side. These details outline features of the aircraft, such as cockpit structure, engine exhaust, access doors, rivet lines, engine cowl, and the like. The printing is easily accomplished in the flat prior to assembly making the procedure easy and fast to accomplish.

Still another object of the invention allows the flat material to be bent in an aerodynamic shape for - ing the wing to give lift to the surface. This shape is maintained by the matching cutout in the fuselage and is easily preserved as the attachment is made in this area and the rear portion is interlocked into a cutout. Yet another object of the invention allows the model to be propelled by either twisted rubber bands, or an electric motor, with equal ease, and since the fuselage is hollow, the elements are located within covering the apparatus completely. This arrangement does not distract from the physical appearance of the airplane, as the outside is not unencumbered with the propulsion means that would be dissimilar to the engine in the original aircract.

A final object of the invention provides means to fabricate the model using die cut parts, silk screen, or printed outside surface, and injection molded thermo¬ plastic accessories and findings. These fabrication procedures lend themself to high production, cost effec¬ tive manufacturing techniques that allow the model to be competitively priced and have a pleasant accurate physical appearance attractive to the young and old alike

These and other objects and advantages of the pre¬ sent invention will become apparent from the subsequent detailed description of the preferred embodiment and the appended claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 is a partial isometric view of the pre- ferred embodiment in its assembled mode.

FIGURE 2 is a cross-sectional view taken along lines 2-2 of FIGURE 1 illustrating a cross-section of the fuselage.

FIGURE 3 is a cross-sectional view taken along lines 3-3 of FIGURE 1 illustrating a cross-section of the fuselage.

FIGURE 4 is a cross-sectional view taken along lines 4-4 of FIGURE 1 illustrating a cross-section of the wing. FIGURE 5 is a cross-sectional view taken along lines 5-5 of FIGURE 1 illustrating the twisted rubber band means of propulsion.

FIGURE 6 is a cross-sectional view taken along lines 6-6 of FIGURE 1 illustrating an electric motor and batteries for propulsion.

BEST MODE FOR CARRYING OUT THE INVENTION

The best mode for carrying out the invention is presented in terms of a preferred and a second embodi¬ ment. Both embodiments are primarily designed using the same basic structure, except for the propeller ro¬ tating means which may be either rubber band or electric motor. The preferred embodiment, as shown in FIGURES 1 through 5 is comprised of a fuselage 20 having the basic

shape of the original aircraft formed with two sides and a bottom. The sides 22 of the fuselage 20 are identical in shape with markings on opposite surfaces and are bonded together with adhesive, or the like, at the top and are formed into an isosceles triangles having the unequal angle at the top. The triangle shape starts somewhat below the extreme upper surface at a point in a straight line continuing from front to back of the model. This arrangement allows the cockpit area, or other projecting surfaces, to be joined flat with the triangle starting in a full portion of the body. The triangular shape has a height to width ratio of from 1.12 : 1.0 to 1.50 : 1.0 tapering such that the model simulates the contour of the original airplane. The bottom 24 is a separate piece that is glued to the sides, and is basically flat, tapering from the front to the rear gradually or even widening at the wing area according to the shape of the aircraft from which the model is duplicated. The fuselage 20 further contains a projecting tendon hook 26 on each side near the top above the area where the wing is located. This hook is two-sided and grips the outside surface of the fuselage 20 on either side with hooks projecting in opposite directions. The bottom 24 of the fuselage 20 contains a wing attaching eye 28 at the portion of the body where the forward segment of the wing interfaces and the rearward area contains a recess 30 which encompasses a wing trailing edge. The fuselage 20 further contains an inverted dove¬ tail fastener 32 at the upper trailing end for attach¬ ment of the tail. All of the above fasteners 26, 28 and 32 are fabricated using an injection molded thermoplastic material. Each fastener consist of a two-part assembly that provides an extended surface on each side of the body or fuselage with connecting penetration therethrough

providing a permanent secure anchoring joint over a relatively large surface area of the structure.

An aerodynamic shaped wing 34 is also die cut to the desired configuration and contains a pair of tendon supporting hooks 36 on the top surface each equally spaced from the normal longitudinal centerline of the model. The wing 34 also contains an attaching inter¬ locking medial member 38 on the mid position of the top at the above centerline. Both fasteners 36 and 38 are constructed in a similar manner, as above, using the same basic materials. Figure 1 depicts the upper attachments, and Figure 5 the interface connections. The wing 34 is positioned beneath the fuselage 20 with the wing attaching eye 28 penetrating the interlocking member 38 and the recess 30 gripping the trailing edge of the wing holding it in place on the front and back portions. The shape of the wing is bent into an aero¬ dynamic contour creating the necessary lift allowing the airplane to maintain flight. A pair of wing supporting tendons 40, having a yoke 42 on each tip, are attached on one end to the tendon hook 26 on the fuselage 20 and to corresponding wing supporting tendons 40 on the other end through the yokes 42. These tendons 40 create a brace transmitting loads imposed on the wing 34 to the common tendon hook 26 on the fuselage 20 giving support and strength to the wing. The combination of the bend and the braces add sufficient stability to the wing to achieve the re¬ quired structural integrity. The airplane further includes a tail consisting of an elevator 44 and a vertical stabilizer 48. The elevator contains a tail attaching plate 46 with open¬ ings that receive the inverted dovetail fastener 32. The elevator 44 is placed on the trailing end of the fuselage 20 with the fastener 32 interfacing through the plate 46 and the vertical stabilizer 48 is then

positioned at right angles to the elevator 44. The stabilizer 48 contains a projecting finger 50 that slides into the dovetail of the fastener 32 on top of the plate 46 uniting both elements mechanically to the fuselage 20. The tail, as an assembly, provides the horizontal and vertical stability for flight of the model.

The above components, with the exception of the fasteners and tendons, are fabricated of a foamed thermosetting material, such as expanded urethane foam, polystyrene beads, or the like, preferably having a more dense surface or skin on the outside. The fastener? and tendon yokes 42 may be made of any suitable thermo¬ plastic material, such as polycarbonate, polyethylene, polypropylene, polyvinylchloride, and the like.

The landing gear consists of a pair of wheels 52 rotatably attached to an inverted "V" shaped wire strut 54. The apex of the strut 54 is bent angularly forming a clip-like end which is inserted into the wing attaching eye 28, best illustrated in Figure 1, and wedgingly rests upon the interlocking medial member 38 forming a secure but removable attachment of the landing gear to the wing 34 and fuselage 20. The landing gear is sufficiently resilient to absorb shock loads imposed upon the model when the airplane is landing. Further, the wheels 52 rotate freely on the strut 54 providing mobility on a hard surface, such as the ground.

The force placed on the ambient air to propel the model is provided by an airscrew or propeller 56 rotat- ably attached to the front of the fuselage 20. The propeller 56 is actuated by means to rotate which sus¬ tains sufficient endurance to allow free flight of the model. In the preferred embodiment this means to ro¬ tate is provided by a twisted rubber band 58, which is attached on one end to a propeller hook 60, integral with the propeller 56, and to a hooked rear fuselage

skid 62 on the other. The skid 62 is positioned on the bottom of the fuselage 20 near the trailing end, therefore, allowing an extended span for the rubber band 58 almost the entire length of the model. The propeller 56 is rotated in one direction manually and is then released and unwinds, causing the air to be moved over the wings sustaining flight.

The second embodiment replaces the rubber band 58 and ancillary elements with an electric motor 64 powered by dry cell storage batteries 66. The pro¬ peller 56 is attached directly to the shaft of the motor 64, or may utilize a gear train for speed control and transmits torsional rotation through the electro¬ motive force of the motor. The batteries 66 are posi- tioned preferably within the fuselage 20 near the center of balance of the airplane and conduct the electrical power to the motor 64 through insulated wires.

The model is, by nature, having basically flat surfaces to start with, in its assembly process allows printing or silk screening to be applied to the surface outlining the details of the aircraft and the appropri¬ ate markings.

Assembly and dissembly of the model are easily accomplished using the procedures outlined and the fittings provided.

While the invention has been described in complete detail and pictorially shown in the accompanying draw¬ ings _r it is not to be limited to such details, since many changes and modifications may be in the invention without departing from the spirit and the scope thereof. Hence, it is described to cover any and all modifications and forms which may come within the language and scope of the appended claims.