AU714378B2

AU714378B2 - Toy aircraft, flyable by remote guidance in a closed area, particularly in a room

Info

Publication number: AU714378B2
Application number: AU67032/96A
Authority: AU
Inventors: Frederic Deparis; Jerome Deparis
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-07-26
Filing date: 1996-07-25
Publication date: 1999-12-23
Anticipated expiration: 2016-07-25
Also published as: DE69601879T2; FR2737130B1; ES2132945T3; DE69601879D1; CN1195998A; JPH11509758A; CA2227736A1; AU6703296A; EP0840641A1; FR2737130A1; CN1135130C; EP0840641B1; ATE177968T1; WO1997004848A1

Abstract

A toy aircraft for use in a confined space, particularly a room, including a model aircraft (1) with an electric motor (11) driving a propeller (19) and means for controlling the model aircraft in flight, a remote control device (2) comprising an electrical power supply (21) and electrical control means for controlling the flight of the model aircraft, and a flexible cable (3) electrically connecting the remote control device (2) to the model aircraft (1) to supply power to the electric motor (11) from the electrical power supply and to connect said electrical control means to said steering means. The wing loading of the model aircraft (1) trailing the connecting cable (3) is </= 1.5 g/dm<2>, and the flexible cable is attached to the underside of the model aircraft adjacent to the centre of gravity thereof.

Description

TOY AIRCRAFT, FLYABLE BY REMOTE GUIDANCE IN A CLOSED AREA, PARTICULARLY IN A ROOM This invention relates to a toy aircraft that can be flown by remote guidance within a closed area protected from the wind, and particularly in a room.

The room in which the aircraft can fly may be a relatively small room such as a room in an apartment or a house (living room, bedroom, games room, etc.).

Children very much like toy aircraft, particularly when they can be made to fly. The most sophisticated are small scale models reproducing the main characteristics of a genuine aircraft and which are remote controlled by radio. They have a thermal combustion engine or an electric motor to rotate the propeller, a fuel tank or a battery and rudder and elevator control mechanisms. The rudder and elevator motor and control mechanisms are controlled by means of a transmitter located in a control box and a receiver installed in the aircraft. These small scale models are intended for use by teenagers or adults, and in most cases can hardly be qualified as toys.

These aircraft remote controlled by radio are relatively heavy, and consequently fly at a relatively high speed. They are only suitable for outdoors use.

No structural modification could transform them into an indoors toy to fly in a small area such as a room in an apartment. The need to find an open site considerably restricts the use of these aircraft.

The only known aircraft capable of flying indoors are powered by elastic bands, and are very lightweight and can be used without danger in living rooms. However, they cannot be controlled and SP 10826 JL S32/2271/CD 2 consequently the interest in them is limited. Furthermore, their flight time is only a few seconds, except for competition prototypes for use by adults only.

Therefore, there are no remote controlled flying toy aircraft designed for use in a small area such as a room or an apartment. Nor is it possible to modify existing remote controlled aircraft so that they can be used as toys in such an area.

This invention was designed to provide a solution to this problem. It was used to design an easy-to-use flying machine.

Its objective is a toy aircraft capable of flying in a closed area and particularly in a room, comprising: a model aircraft fitted with an electric motor driving a propeller; a remote control device controlling the flight of the model aircraft, comprising an electrical power source and electrical means of controlling the flight of the model aircraft; a flexible cable forming the electrical connection between the remote :....control device and the model aircraft to power the electric motor from the S•electrical power source; characterised in that the model aircraft is equipped with actuation means for acting on a flight direction, the flexible cable also connecting said 20 electrical control means to said actuation means and being attached under the model aircraft close to its center of gravity, the wing loading of the model aircraft supporting the connecting cable being 1.5 g/dm 2 a, 0a'a a *o .o a a.

a If the remote controlled flying aircraft according to the invention is to be used by a child, which it probably would be for this type of object, it is essential that it should not be dangerous, not- only when it is flying but also when the child is handling it. This toy must also be sufficiently robust to resist shocks and manipulations, while remaining extremely lightweight.

The invention will be better understood and other advantages and specific features will become obvious in reading the following description given as a non-restrictive example, with reference to the drawings in the appendix, among which: figure 1 is an overall view of the toy aircraft according to the invention, the model aircraft being shown in flight; figure 2 shows an electric connecting cable that can be used in the toy aircraft according to the invention; figure 3 is an exploded view of a first variant of the model aircraft according to the invention; figure 4 is a detailed view showing the rudder of the model aircraft according to the invention, and its motor drive; figure 5 is a bottom view of the fuselage and wings of the first variant of the model aircraft according to the invention; figure 6 is a structural view of a second variant of the model aircraft according to the invention.

The maximum speed at which the model aircraft can fly without causing any problems in a small area SP 10826 JL S32/2271/CD such as an apartment has been estimated at 2 m/s. A child can easily control the flight of the model aircraft at this low speed. The connecting cable is not designed to be tight. Therefore, the flight domain is not restricted to the surface of a sphere as in the case of circular flight. The model aircraft can move freely in all directions.

The model aircraft must be very lightweight if it is to fly at such a low speed. It is estimated that the airborne weight of the model aircraft carrying the connecting cable must be 1.5 g/dm 2 This low value of the airborne weight can be obtained because the toy aircraft according to the invention has a connecting cable and does not need an energy source or a radio control receiver onboard the model aircraft.

The example embodiments that will now be described offer very lightweight and robust model aircraft which are in no way dangerous, which is very important for a toy.

Figure 1 shows three essential elements of the toy aircraft according to the invention; the model aircraft 1, the control device 2 and the cable 3 forming the electrical connection between the model aircraft and the control device.

The control device 2 comprises a battery 21 acting as a source of electrical power that can be put in the circuit by switch 22. To make the control device more attractive, it can be made in the shape of a modern aircraft flight control wheel, in other words in the form of two handles 23 and 24 attached to the central part 25 which contains all electrical and electronic control elements. The control device 26 located on the left handle 23 controls the model SP 10826 JL S32/2271/CD aircraft motor 11 that drives the propeller 19. The aircraft rudder control device 27 is located on the right handle 24.

To reduce the weight, it was decided to fix the elevator 13, the aircraft being made to move up or down by changing the motor speed.

The control devices 26 and 27 activate variable resistances or electronic power variators that are easily available on the market. The voltage at the motor terminals must be adjustable from 0 to the maximum voltage. The voltage at the rudder actuator terminals (which will be described later) must be adjustable between a maximum negative voltage value and a maximum positive voltage value, this maximum voltage possibly being different from the voltage powering the motor. The two control devices 26 and 27 are fitted with springs which return them to a neutral position corresponding to 0 V in both cases.

The electrical connecting cable must be as lightweight as possible, consequently the electrical wires in it must be as lightweight as possible, and therefore as thin as possible. Therefore, the current intensity passing through them must be limited to a low value and consequently a relatively high voltage is necessary to ensure that sufficient power is available.

For example, the maximum power supply voltage to the electrical motor 11 may be 9 V, whereas the actuator control voltage may vary between 9 V and 9 V.

The electrical connecting cable 3 must be flexible and very lightweight so that it does not hinder movement of the model aircraft 1. A length of about 1.75 m appears to be appropriate for operation in a medium sized room in the home. For the toy aircraft SP 10826 JL S32/2271/CD according to the invention, an electrical cable of this length is suggested weighing only 0.6 g, which is about 0.35 g/m, without the connectors. This cable is -shown by itself in figure 2. It is composed of- four conducting wires 31, 32, 33, and 34 each 0.1 mm diameter, two wires being used to power the electric motor and two wires being reserved to control the rudder. These wires are made of copper and are electrically insulated by varnish. They can thus be grouped in a fold 35 made from plastic ribbon folded in two. After inserting the wires, the two sides of the fold are glued together. The plastic ribbon used may have a width of 4 mm and thickness of 10 to 12 pm, which is a typical thickness for plastic films manufacturers. It is a good idea to use a plastic that is difficult to tear, for example polyethylene or polypropylene, because it stretches a lot before it tears.

The cable is terminated at the control device end by a connector with four contacts. Another connector with four contacts connects the cable to the model aircraft. The weight of this connector may be equal to or less than 0.1 g if it is chosen among miniaturized connectors used in computers or in portable telephone equipment.

These connectors will preferably be sized so that they can easily be disconnected whenever any abnormal force is applied to them. This protects the electrical cable and the model aircraft from excessive mechanical stresses.

Figure 3 shows an exploded view of a model aircraft 1 with the wings incomplete. For example, its wingspan may be 45 cm, its length 40 cm, the area of SP 10826 JL S32/2271/CD the wings 4.5 dm 2 and its weight 6 g. The electrical connecting cable is attached to the model aircraft by its connector, below the model and close to its center of gravity.

The model aircraft may be divided into the following subassemblies: the motor propulsion unit 100; the rudder actuator 200; the fuselage 14 and the wing leading edges the rest of the wings; the elevator 13 and the rudder 12.

A good distribution of the weight of each subassembly according to the invention is as follows: motor propulsion unit 2.5 g; actuator 0.3 g; fuselage and leading edges 1.5 g; the rest of the wings 1 g; the elevator and rudder 0.3 g; half of the length of the cable with its connector at the model aircraft end 0.4 g.

This gives a total of 6 g.

The motor propulsion unit 100 is composed of the electric motor 11ii, a propeller and a spinner 106.

The motor 11 must have an excellent power to weight ratio. It could be a DC motor with brushes and very powerful magnets (rare earth magnets). The consumption of this motor is of the order of 200 mA at a power supply voltage of 7 V. The motor propulsion unit must be capable of lifting two thirds of the weight of the aircraft when stopped, in this case 4 g, in other words a little less than twice the weight of the motor propulsion unit. The motor may be of the SP 10826 JL S32/2271/CD type used in micromechanisms and equipped with samarium-cobalt magnets. This type of motor is available at a weight of about 3.2 g. This weight could be reduced by judiciously choosing materials and dimensions of component elements.

The propeller must not be dangerous. This is achieved by making it flexible, which contributes to its strength. It comprises a hub 101 which fits on and is glued onto the spindle 111 of motor 11, and two blades 102.

One blade is made of a flexible plastic film about 50 pm thick folded in two, and which is slightly curved. Each blade shank 103 on the hub fits into the pleat of each fold 102 forming a blade. The facing sides of each fold are glued together, and contain the shank of the corresponding blade.

The spinner 106 protects the propeller and the motor. It is preferably made of expanded plastic to absorb shocks.

More precisely, the elements contained in the motor propulsion unit have the following characteristics: motor 2.25 g; propeller plus spinner 0.25 g, including 0.02 g for the spinner; propeller diameter 8 cm; propeller pitch 150; maximum motor rotation speed 6000 rpm.

Figure 4 contains a detailed view of the model aircraft showing the rudder 12 and its actuator 200.

This actuator must be very lightweight since the yaw inertia of the model aircraft must be very low so that it is sufficiently controllable in turns. Its weight SP 10826 JL S32/2271/CD

M

is preferably of the order of 0.3 g. It is advantageously of the type used for mobile fittings in dial multimeters. It comprises a permanent magnet 201 made of Sm-Co or Fe-Nd, connected to a spindle 202 (for example made of piano wire) rigidly attached to the rudder 12 and forming the hinge pin for this rudder.

The magnet 201 is placed inside a flat induction coil 203, the ends of which are electrically connected to two of the wires in the electrical connection cable.

Depending on the intensity and direction of the current passing through coil 203, the magnet 201 is subject to a magnetic field with a variable amplitude and direction. The result is a pair of forces that rotate magnet 201, and therefore the rudder 12 which is attached to it.

The induction coil 203 is attached to the fuselage 14 (see figure 3) by a piece of adhesive tape.

A plastic strand 16 in two parts is fixed firstly to the fuselage 14 by gluing and secondly to the rudder 12. It forms a spring element that tends to keep the rudder in the neutral position.

In order to reduce the rudder control torque, the rudder is compensated (its axis of rotation 202 divides its surface into two almost equal parts) and is balanced (the axis of rotation 202 passes through the center of gravity of the mobile equipment) Figure 4 also shows the composition of the rudder, the elevator also being based on the same principle. A flexible plastic strand 204 with diameter 0.6 mm is closed on itself and heat sealed to form the periphery of the elevator. The plastic strand 16 is glued to strand 204 at and behind the actuator 200 that it surrounds. An 8 pm thick plastic film 205 is SP 10826 JL S32/2271/CD stretched on strand 204 and the edge of the film is folded around strand 204 so that it can be glued or heat sealed to itself.

We will now describe how the fuselage and the wing leading edges are formed, with reference to figures 3 and 5. In order to be sufficiently lightweight and stiff when flight forces are applied to it, this part is composed of an envelope consisting of a 10 pm thick plastic film which forms the fuselage 14 and the leading edges 15. The connection between the fuselage and the leading edges (by gluing or heat sealing) must be sufficiently rigid to prevent the wings from collapsing. A connecting collar may be necessary at this location to increase the stiffness of the link. The leading edges 15 are preferably slightly tapered, their diameter tending to reduce with the distance from the fuselage. Each leading edge is fixed to the fuselage so that the corresponding wing is in the form of a dihedron with an angle of a few degrees and with an angle of incidence of 50. The envelope may also include tabs 10 where the wheels would usually be to support the model aircraft when it is on the ground.

Alternatively, these tabs may be part of a different structure and added on to the model aircraft.

The envelope is inflated to a pressure about mbars above atmospheric pressure. The envelope may be sealed or it may have a reinflation valve.

The electric motor 11 is glued to the front of the fuselage 14, possibly after inserting a reinforcing washer.

As can be seen in figure 5, the remainder of each wing is composed of a flexible plastic strand about 1 mm diameter acting as the leading edge, and a SP 10826 JL S32/2271/CD plastic film 18 about 8 pm thick. The cord 17 is attached by one of its ends to the distal end of the leading edge 15 and to the fuselage 14 at its *other end. Film 18 is stretched between the leading edge the trailing edge 17 and the fuselage. It is fixed to the leading edge and to the fuselage by gluing or by heat sealing. It is fixed to itself by gluing or heat sealing, after folding over strand 17.

Figure 6 shows the structure of another model aircraft. In this variant, the fuselage and leading edges of the wings are formed of plastic tubes with very thin surfaces. Drinking straws are a good example of usable tubes. The diameter of drinking straws varies from 5 to 7 mm and their wall thickness is 150 pm. The landing gear may also be composed of these straws.

A central tube 50 forms the main axis of the structure. The motor propulsion unit shall be slid into and glued onto its front end. The elevator and the rudder shall be fixed onto its rear end. The front part of the tube 50 also supports the landing gear composed of two tube segments 51 and 52. The tube segments 51 and 52 support tubes 53 and 54, respectively, acting as leading edges. A small connecting tube 55 fixed between segments 51 and 52 stiffens the landing gear. A small tube 56 is also added to tube 50 perpendicular to it.

Junction parts references 57 to 60 are used to assemble the tubes together. The shapes of these parts are adapted to the tubes to be connected.

Advantageously, they will be made of plastic. The distance between junction parts 57 and 60 is equal to SP 10826

JL

S32/2271/CD the chord of the wing. The other elements making up the model aircraft are glued to the tubes.

The structure obtained may be coated with a colored plastic film, with a thickness of 6 or 8 pm.

The bending and torsional stiffnesses of the wings used on the two model aircraft described above as an example, may be increased by adding guys. Guys placed below the wings are particularly efficient since they limit bending due to the weight of the aircraft during flight.

One good method of adding guys consists of connecting a thread between near the outer end of each wing leading edge, and the bottom of the corresponding landing gear. Furthermore, if the length of each of the guys is made adjustable by appropriate means at the attachment points to the landing gear, the following two possibilities are obtained: by pulling the left and right guys similarly, therefore bending each of the two wings equally, the incidence of the wings is modified thus adjusting the longitudinal stability of the aircraft; by pulling the two guides differently, the wings may be twisted or untwisted, thus adjusting the aircraft stability in yaw and in roll.

These guides can be used to make a simplified version of this toy. The simplified aircraft has a fixed rudder and it is then impossible to control it in flight. Since there is no corresponding actuator, the electrical connecting cable only contains two wires and the control device no longer has any direction control.

The toy user adjusts the radius of turn of the aircraft before the flight starts. The adjustment consists of SP 10826 JL S32/2271/CD shortening the wing guy on the inside of the turn, to bend the wing even further.

One guy 40 can be seen on the model aircraft 1 shown in figure i. It is located between a tab representing a wheel and the leading edge of the corresponding wing.

Guys 61 and 62 are also shown in figure 6. Guy 61 is placed between tube 51 and the trailing edge of the corresponding wing. Guy 62 is placed between tube 52 and the trailing edge of the corresponding wing.

The toy is not dangerous due to its low weight and low inertia, its low power (less than 3 W) and the flexibility of its components and particularly the propeller.

SP 10826 JL S32/2271/CD

Claims

1. A toy aircraft capable of flying in a closed space and particularly in a room, comprising: a model aircraft fitted with an electric motor driving a propeller; a remote control device controlling the flight of the model aircraft, comprising an electrical power source and electrical means of controlling the flight of the model aircraft; a flexible cable forming the electrical connection between the remote control device and the model aircraft to power the electric motor from the electrical power source; characterised in that the model aircraft is equipped with actuation means for acting on a flight direction, the flexible cable also connecting said electrical control means to said actuation means and being attached under the model aircraft close to its center of gravity, the wing loading of the model 15 aircraft supporting the connecting cable being 1.5 g/dm

2 A toy aircraft according to claim 1, characterised in that the model aircraft is equipped with a fixed elevator, the flight direction being modified by making the model aircraft go up or down by varying the motor speed, the means of controlling the aircraft going up or down then consisting of the 20 electric motor, the corresponding electrical control means consisting of means of varying the electrical energy supplied to the motor by the electrical power source.

3. A toy aircraft according to either of claims 1 or 2, characterised in that the means for making a turn comprise a permanent magnet fixed to a hinge pin 25 itself fixed to a rudder and an induction coil fixed to the model aircraft and capable of applying the action of a magnetic field generated by passing a DC electrical current in said induction coil to said permanent magnet, the S"corresponding electrical control means consisting of means of varying the intensity of the DC electrical current passing through the induction coil.

4. A toy aircraft according to claim 3, characterised in that said means of varying the intensity of the DC electrical current passing through the induction coil comprise means of varying the DC voltage applied to the terminals of the induction coil to generate said electrical current, and capable of varying this DC voltage making it negative or positive about the zero value corresponding to the neutral position of the rudder.

A toy aircraft according to any one of claims 3 to 4, characterised in that the model aircraft comprises a spring tending to hold the rudder in its neutral position.

6. A toy aircraft according to claim 5, characterised in that said spring comprises at least one plastic strand mechanically connecting the rudder to the fuselage of the model aircraft.

7. A toy aircraft according to any one of claims 1 to 6, characterised in that the electric motor is a DC motor with rare earth brushes and magnets.

8. A toy aircraft according to any one of claims 1 to 7, characterised in that each blade of the propeller is composed of a folded flexible plastic film, the sides of which are fixed to each other.

9. A toy aircraft according to claim 8, characterised in that each blade is fixed to the hub of the propeller by a blade shank fixed to the hub, penetrating into the pleat of the fold forming the blade so that it is fixed in it. 15

10. A toy aircraft according to any one of claims 1 to 9, characterised in that i. "'the model aircraft comprises a spinner made of expanded plastic.

11. A toy aircraft according to any one of claims 1 to 10, characterised in that the fuselage and the leading edges of the wings are composed of an -envelope of inflated plastic film.

12. A toy aircraft according to claim 11, characterised in that the plastic film envelope is inflated to a pressure exceeding atmospheric pressure by about :'.mbars.

13. A toy aircraft according to any one of claims 11 or 12, characterised in that each wing comprises a flexible strand attached at one of its ends to the S 25 distal end of the leading edge, and at its other end to the fuselage to delimit the wing leading edge, a plastic film being fixed between the leading edge, the strand delimiting the leading edge and the fuselage to complete the wing.

14. A toy aircraft according to any one of claims 1 to 10, characterised in that the fuselage and the leading edges of the wings are made from tubes.

15. A toy aircraft according to any one of claims 1 to 14, characterised in that the elevator of the model aircraft is composed of a flexible strand delimiting its extent and supporting a plastic film.

16. A toy aircraft according to any one of claims 1 to 15, characterised in that the model aircraft rudder is composed of a flexible strand delimiting its extent and supporting a plastic film.

17. A toy aircraft according to any one of claims 1 to 16, characterised in that the model aircraft includes tabs instead of wheels to support it when it is on the floor.

18. A toy aircraft according to any one of claims 1 to 17, characterised in that the remote control device is contained in a box in the form of a modern aircraft flight control wheel.

19. A toy aircraft according to claim 18, characterised in that one of the flight control wheel handles is fitted with a maneuverable device used to make the model aircraft go up or down in flight while the other handle of the flight control wheel comprises a maneuverable device used to make the model aircraft turn.

A toy aircraft according to any one of the previous claims, characterised in that the cable comprises insulated wires, conducting electricity, housed in the pleat of a fold obtained by longitudinally folding a flexible ribbon, the 15 facing sides of which are fixed to each other. •oo

21. A toy aircraft according to claim 20, characterised in that the flexible ribbon is a plastic film.

22. A toy aircraft according to any one of the previous claims, characterised in that the cable is electrically connected to the model aircraft by a disconnectable pin.

23. A toy aircraft according to any one of the previous claims, characterised in that it includes guys to increase the bending and torsional stiffnesses of the wings.

24. A toy aircraft according to claim 23, characterised in that the length of the guys is adjustable. A toy aircraft substantially as hereinbefore described with reference to "."and/or as shown in Figures 1 and 2, or Figures 3, 4 and 5, or Figure 6 of the drawings. DATED this second day of November 1999 Jerome Deparis Patent Attorneys for the Applicant: F.B. RICE CO.