GB1564900A - Models propelled by elastic motors - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO MODELS PROPELLED BY ELASTIC MOTORS (71) We, ALLIED INTERNATIONAL DE SIGNERS LIMITED, a British Company, of 10 Rathbone Place, London W1P 2DN, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to apparatus of the kind powered by an elastic motor connected between a rotary propelling means and an anchorage. Apparatus of this kind includes model aeroplanes and model ships.

According to this invention there is provided a self-propelled model comprising a body having a rotary propelling means driven by a motor in the form of a length of elastic material connected at one end to an anchorage and at its other end to the rotary propelling means, the motor being wound up by twisting the length of elastic material, control means providing a control surface which is acted on by the fluid wherein the model moves and which is pivotally adjustable from a first position to a second position relative to a body part of the model thereby to alter the path of movement of the model, the control means being resiliently loaded by the motor force to move the control surface into said first position when the motor is fully wound, and biasing means loading the control means to pivot the control surface towards said second position against the motor force, the arrangement being such that as the motor runs down, the motor force reduces to such an extent that the biasing means overcomes the effect of the motor force on the control means and causes the control surface to be pivoted into said second position.

In a model aeroplane, the control action of the control means may be to adjust the rudder setting and/or the elevator setting. In a particularly simple arrangement according to the invention, the fuselage of the aeroplane may incorporate in its length a hinge enabling the whole of the rear end of the fuselage including the tail to pivot; if the control action is to be in effect an elevator action the hinge axis will be transverse and horizontal and if the action is to be simply a steering action the hinge axis will be transverse and vertical, but it is also possible to arrange the hinge axis to be transverse (i.e. normal to the lengthwise axis of the aeroplane) and inclined to be vertical so as both to reduce the angle of descent and cause the aeroplane to turn as the elastic approaches the unwound condition.

By incorporating a lost motion connection in the control means, the control means can be arranged to actuate two or more control actions in succession.

In the case of model submarines the control action may be a steering action and/or a climbing or diving manoeuvre. In the case of model ships the control action may be a steering action.

Some embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a simple model aeroplane incorporating the invention Figure 2 shows an exploded fragmentary view of part of the model, Figure 3 shows the tail section of a further model aeroplane embodying the invention, the control action being actuated in response to change of torque in the elastic motor drive, Figure 4 shows the tail section of a third model aeroplane embodying the invention, a control action being actuated in response to changes of torque in the elastic of the motor, Figures 5 and 6 show further similar arrangements in which the control action is actuated by changes of tension in the elastic, and Figures 6A, 6B and 6C show the sequence of movements in operation of the arrangement of Figure 6.

Referring to Figures 1 and 2 of the drawings, the fuselage of the aeroplane is formed by two spars 10, 11 disposed end to end and connected together by a hinge coupling 12.

These spars may for example be square or rectangular section lengths of balsa wood.

The front spar 10 carries the wings 13 and has at its front end a capping piece 14 with an integral short downwardly-projecting arm 15 which provides a bearing for a short shaft carrying a propeller 16. The rear end of the shaft is hooked for the attachment thereto of one end of a length of elastic 17 powering the aeroplane.

The coupling 12 is in the form of a moulding made from polypropylene and comprising two sockets 18, 19 interconnected by an integral hinge 20 arranged with the hinge axis horizontal. The two sockets 18, 19 respectively receive the rear end of the forward spar 10 and the forward end of the rear spar 11.

The rear spar carries a rudder 21 and tailpiece 22, and it will therefore be apparent that pivoting of the rear spar about the hinge alters the angle of attack of the tailpiece 22.

The rear socket 19 of the coupling has upwardly and downwardly projecting arms 23, 24 and the arm 24 provides an anchorage for the rear end of the elastic 17. The front socket 18 has a rearwardly projecting lug 25 and the arm 24 comes into abutment with this lug when the two sockets are disposed colinearly, so that from the colinear position the rear socket 19 and spar 11 can only move to incline upwardly. A short spring 26 is connected between the upwardly projecting arm 23 and a lug 27 on the front spar 10.

Arm 23 may have holes spaced along its length to provide alternative points of attachment for the spring 26 and thus adjustment of the tension and line of action of the spring.

For the same purpose the front spar may have spaced lugs 27 to provide alternative points of attachment for the front end of the spring.

The spring 26 is strong enough to swivel the socket 19 and spar 11 upward when the elastic is unwound, but when the elastic is fully wound its tension overcomes the spring tension and holds the lever against lug 25 and hence holds the rear socket and spar 11 in line with the front socket and spar 10. When the elastic has unwound to some extent during flight of the aeroplane, the tension in the elastic falls sufficiently to allow spring 26 to incline the rear spar and tailpiece upwardly.

The normal action of a model aeroplane powered by an elastic motor as the elastic unwinds is to climb, stall and dive into the ground. The action of the illustrated mechanism is to cause the angle of attack of the tailplane to increase during the latter part of the aeroplane's flight so that a final nose dive into the ground is avoided and the length of flight is increased.

If the axis of the hinge is disposed vertically a rudder action is obtained instead of an elevator action.

If necessary, to facilitate moulding of the coupling it may be made in two parts connected together by a snap-in type of peg hinge.

If the sockets are made, say, octagonal in cross-section, the control action performed can be varied to make it effectively a rudder action only, an elevator action only, or a combined rudder and elevator action.

The hinge coupling may if desired be disposed near the propeller so that the propeller is swivelled instead of the tail.

Referring to the embodiment illustrated in Figure 3, the hollow fuselage of the model aeroplane houses the elastic band 110, and an anchorage hook 111 is attached to a shaft 112 which is rotatable and axially slidable in a sleeve 113 fixed at the rear end of the fuselage.

The rearward end of shaft 112 projects beyond the sleeve and carries a crank 114, and a tension spring 115 is connected between the crank and a fixed arm 116 on sleeve 113. A fixed vertically extending pin 117 on sleeve 113 provides a pivot for the rudder 118 and two oppositely projecting horizontal pins 119 provide respective pivots for the two tail planes 120. A vertical pin 121 on the forward portion of shaft 112 engages in a ring 122 on the lower edge portion of the rudder forward of pin 117 and a horizontal pin 123 on shaft 112 engages in a ring 124 on the forward end portion of one of the tail planes. The two tail planes are connected together by a bracket 126 for swivelling movement together about the pins 119.

As the elastic is wound up in the appropriate direction, the tension spring 115 is gradually extended owing to the increasing torque necessary to prevent the elastic from unwinding itself by rotating the anchorage hook 111. A stop (not shown), which may be adjustable, is provided n the sleeve to limit this movement of the crank and hence the extension of the spring, and at this stage the rudder and tail planes are disposed in their positions for take-off and normal flight. Thus when the model is released, it flies normally until the torque in the elastic falls to a value at which the tension spring commences to pull the crank away from the stop. This causes the shaft 112 to start to turn and applies a steering action to the rudder about pivot pin 117 and a climbing or diving action to the tail planes, swivelling them together about their pivot pins 119.

By placing a small compression spring about the shaft 112 between the crank 114 and the adjacent end of the sleeve 113, the shaft 112 may be caused to move axially by the compression spring as the tension in the elastic falls, as well as rotating as previously described. A cam of generally conical form may be mounted on an extension of shaft 112 beyond the crank and may engage a follower connected to one of the tail planes or to the rudder, so that axial movement of the cam, instead of the rotation of the shaft, controls the tail planes or the rudder, and enables one control action to be arranged to occur at a different time to the other. It will be understood that the ring 122 or ring 124, whichever is employed in this modified arrangement, will provide a slot extending lengthwise of the shaft 112 to accommodate the axial movement of the shaft.

In the arrangement of Figure 4, the rearward end of the elastic 130 of a model aeroplane is anchored to an upright pin 131 carried by arms 132 of twin levers 133 pivotally mounted about a vertical axle 134, which is mounted in lugs on the side of the fuselage. The top and bottom ends of pin 131 project through slots in the top and bottom of the fuselage, allowing the levers and pin to swing. The other arms 136 of the levers carry a pin 137 to which one end of a tension spring 138 is connected. The other end of the spring is connected to one of several alternative attachment points 139 on a plate member 140 secured to the fuselage forwardly of the levers. The rudder is swivellable about a fixed shaft 141 mounted on the fuselage, and a strip 142 to which the lower edge of the rudder is secured has a cam slot 143 in which the upper end 135 of pin 131 engages.A rearwardly extending cam 145 is attached to the arms 136 and is engaged by a follower 146 on the front edge of one of the tail planes 147.

The two tail planes are jointly pivotally mounted on a horizontal shaft 148 carried by the fuselage. A light spring (not shown) maintains the follower 146 in engagement with the cam.

When the elastic is wound up, its tension increases and eventually overcomes the tension in the spring 138 so that the pin extension 135 moves to the forward end of the cam slot 143. At the same time the cam 145 moves rearwardly and is arranged to impart a selected angle of attack to the tail planes so that the model is trimmed as desired. In flight, when the elastic has unwound to a point at which its tension has fallen sufficiently to allow springs 138 to cause the levers 133 to start to swing, the pin extension 135 will start to impart a steering control action to the aircraft and cam 145 will move forward and will reduce the angle of attack of the tail planes, reducing the tendency to stall and allowing the model to land smoothly.

It will be understood that by appropriately shaping the cam slot 143 and the cam 145, the control action can be altered as desired.

Figure 5 shows an arrangement which is similar to that of Figure 3 but which operates in dependence on the tension, and not on the torsion, in the elastic. The rear end of the elastic is attached to a shaft 150 slidably mounted in a sleeve 151 secured in the fuselage. The sleeve carries a vertical pin 152 for the rudder 153 and two horizontal pivot pins 154 for the tail planes 155. The tail planes are coupled together by a bar (not shown) for movement together about the pivot pins 154.

The shaft 150 has secured to it an upwardlyprojecting rod 155 and a horizontally projecting rod 156 which are slidably engaged in respective slots 157, 158 in the sleeve, so as to prevent rotation of the rear anchorage hook.

The rearward end of shaft 150 carries a compression spring 159 which seats against the rear end of the sleeve and acts against a knurled nut 160 screwed on the rear end of the shaft. The bottom edge of the rudder is secured to a strip 161 which projects forwardly of the rudder and is formed with a cam slot 162 in which the vertical rod 155 engages.

Similarly one of the tail planes is secured to a strip 163 which is formed with a cam slot 164 in which the horizontal rod 156 engaged.

When the elastic is wound up the shaft 150 is drawn forward by the tension in the elastic, which overcomes the rearward force applied to the shaft by compression spring 159, and the rods 155, 156 move along the cam slots causing the rudder and tail planes to be set for, say, take-off. As the elastic unwinds during flight, the tension in the elastic falls and the compression spring 159 starts to move the shaft 150 and rods 155, 156 rearward, so that control actions are imparted to the rudder and tail planes by the cam slots.

The form of the cam slots determine the settings of the rudder and tail planes. Adjustment of the nut 160 alters the compression of the spring 159 and hence the timing of the initiation of the manoeuvre or manoeuvres.

Referring now to Figure 6, a model aircraft is shown which is a development of that shown in Figures 1 and 2. The aircraft has a fuselage in the form of a hollow squaresection two-part spar 170A, 170B between the two parts of which is incorporated a double hinge mechanism 171. This mechanism comprises front, intermediate and rear hollow sections 172, 173 and 174. Sections 172 and 174 provide sockets in which the rear end of the front part and the front end of the rear part of the fuselage spar are secured.

The front and rear sections 172, 174 are hinged to the intermediate section 173, the two hinges 175, 176 having their axes vertical and being disposed at opposite sides of the elastic (not shown) which extends through the spar 170A, 170B and through the sections 172, 173 and 174 to a fixed anchorage 177 at the rear end of the fuselage. The ends of the sections adjoining the hinges 175, 176 are angled as shown most clearly in Figure 6C to allow the front and rear sections to become inclined at an obtuse angle with respect to the intermediate section about the respective hinges. The sections are prevented from moving beyond the incline position in the opposition direction by the abutment of lateral projections 180, 181 on the sections 172, 174 respectively with lateral projections 182, 183 respectively on the section 173.A first elastic band 185 extends round projections 180, 182 and a second elastic band 186 extends round projections 181, 183 and these bands urge the projections into abutment with each other to tend to maintain the three sections in line with each other as shown in Figure 6C. Notches 188 are provided on the projections to locate the bands in selected positions enabling the moment arms of the bands about the associated hinges to be adjusted.

The rear part 170B of the fuselage spar has a rudder 190 and tail planes 191 secured to it.

As the elastic motor is wound up, the increasing tension in the elastic reaches values at which its torque about the respective hinges 175, 176 overcomes the torques of the bands 185, 186 about the hinges, and the sections take up the relative positions shown in Figure 6A. The angles on the end faces of the sections are selected so that in this condition, the lengthwise axis of the rear fuselage part 170B is parallel to that of the front part 170A.

The rudder therefore tends to steer the aeroplane straight ahead. The torques exerted by the two bands 185, 186 about the hinges are not equal to each other, and in this example the torque exerted by band 185 is greater than is exerted by band 186. When the model is released, it first flies straight ahead until the falling tension in the elastic allows the band 185 to move the rear fuselage part 170B about the hinge 175 as shown in Figure 6B. The angle of the rudder now causes the model to turn starboard. As the tension in the elastic falls still further, band 186 brings sections 173, 174 back into line with each other as shown in Figure 6C so that for the final part of the flight, the rudder again steers the aircraft in a straight line.

By making the torque of band 186 greater than that of band 185, the model can be caused to make its turn to port instead of starboard.

Since the fuselage spar and the sockets provided by the sections 172, 174 are of square section, the hinge mechanism 171 can be connected to the spar part with the hinge axes horizontal, and in this case the aircraft can be made to make a conventional loop or an 'outside' loop in the middle of its flight by appropriate adjustment of the torque effects of the bands 185, 186 about the hinges.

The double hinge mechanism 171 may be moulded in one piece, with "live" or integral hinges, from polypropylene, but it may be preferable to mould it in separate parts with snap-in peg hinges.

It may be preferable to arrange the double hinge mechanism near the nose of the aircraft, so that the propeller instead of the tail is shifted.

The invention is equally applicable to other elastic motor driven apparatus such as model submarines and other model ships, for example to adjust the steering as the elastic motor unwinds.

WHAT WE CLAIM IS: 1. A self-propelled model comprising a body having a rotary propelling means driven by a motor in the form of a length of elastic material connected at one end to an anchorage and at its other end to the rotary propelling means, the motor being wound up by twisting the length of elastic material, control means providing a control surface which is acted on by the fluid wherein the model moves and which is pivotally adjustable from a first position to a second position relative to a body part of the model thereby to alter the path of movement of the model, the control means being resiliently loaded by the motor force to move the control surface into said first position when the motor is fully wound, and biasing means loading the control means to pivot the control surface towards said second position against the motor force, the arrangement being such that as the motor runs down, the motor force reduces to such an extent that the biasing means overcomes the effect of the motor force on the control means and causes the control surface to be pivoted into said second position.

2. A model as claimed in claim 1, wherein the biasing means acts in opposition to the tension in the elastic material, and operates to impart translatory movement to the anchorage, the control means being connected to the anchorage.

3. A model as claimed in claim 1, wherein the biasing means acts in opposition to torque exerted by the elastic material on the anchorage and operates to rotate the anchorage, the control means being connected to the anchorage.

4. A model as claimed in claim 1, wherein the biasing means acts in opposition to a torque applied by the tension in the length of elastic material to members which are respectively connected to the anchorage and a support for the rotary propelling means, said members being pivotally connected together for limited pivotal movement between the first and second positions about an axis laterally offset from the length of elastic material.

5. A model as claimed in any one of claims 1 to 4, comprising a second control means which provides a second control surface and which is adapted for movement from a first to a second position thereby to actuate a second control action on the path of movement of the model and which is resiliently loaded into its first position by the motor force when the motor is fully wound, and a second biasing means loading the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (14)

**WARNING** start of CLMS field may overlap end of DESC **. 172, 174 respectively with lateral projections 182, 183 respectively on the section 173. A first elastic band 185 extends round projections 180, 182 and a second elastic band 186 extends round projections 181, 183 and these bands urge the projections into abutment with each other to tend to maintain the three sections in line with each other as shown in Figure 6C. Notches 188 are provided on the projections to locate the bands in selected positions enabling the moment arms of the bands about the associated hinges to be adjusted. The rear part 170B of the fuselage spar has a rudder 190 and tail planes 191 secured to it. As the elastic motor is wound up, the increasing tension in the elastic reaches values at which its torque about the respective hinges 175, 176 overcomes the torques of the bands 185, 186 about the hinges, and the sections take up the relative positions shown in Figure 6A. The angles on the end faces of the sections are selected so that in this condition, the lengthwise axis of the rear fuselage part 170B is parallel to that of the front part 170A. The rudder therefore tends to steer the aeroplane straight ahead. The torques exerted by the two bands 185, 186 about the hinges are not equal to each other, and in this example the torque exerted by band 185 is greater than is exerted by band 186. When the model is released, it first flies straight ahead until the falling tension in the elastic allows the band 185 to move the rear fuselage part 170B about the hinge 175 as shown in Figure 6B. The angle of the rudder now causes the model to turn starboard. As the tension in the elastic falls still further, band 186 brings sections 173, 174 back into line with each other as shown in Figure 6C so that for the final part of the flight, the rudder again steers the aircraft in a straight line. By making the torque of band 186 greater than that of band 185, the model can be caused to make its turn to port instead of starboard. Since the fuselage spar and the sockets provided by the sections 172, 174 are of square section, the hinge mechanism 171 can be connected to the spar part with the hinge axes horizontal, and in this case the aircraft can be made to make a conventional loop or an 'outside' loop in the middle of its flight by appropriate adjustment of the torque effects of the bands 185, 186 about the hinges. The double hinge mechanism 171 may be moulded in one piece, with "live" or integral hinges, from polypropylene, but it may be preferable to mould it in separate parts with snap-in peg hinges. It may be preferable to arrange the double hinge mechanism near the nose of the aircraft, so that the propeller instead of the tail is shifted. The invention is equally applicable to other elastic motor driven apparatus such as model submarines and other model ships, for example to adjust the steering as the elastic motor unwinds. WHAT WE CLAIM IS:

1. A self-propelled model comprising a body having a rotary propelling means driven by a motor in the form of a length of elastic material connected at one end to an anchorage and at its other end to the rotary propelling means, the motor being wound up by twisting the length of elastic material, control means providing a control surface which is acted on by the fluid wherein the model moves and which is pivotally adjustable from a first position to a second position relative to a body part of the model thereby to alter the path of movement of the model, the control means being resiliently loaded by the motor force to move the control surface into said first position when the motor is fully wound, and biasing means loading the control means to pivot the control surface towards said second position against the motor force, the arrangement being such that as the motor runs down, the motor force reduces to such an extent that the biasing means overcomes the effect of the motor force on the control means and causes the control surface to be pivoted into said second position.

2. A model as claimed in claim 1, wherein the biasing means acts in opposition to the tension in the elastic material, and operates to impart translatory movement to the anchorage, the control means being connected to the anchorage.

3. A model as claimed in claim 1, wherein the biasing means acts in opposition to torque exerted by the elastic material on the anchorage and operates to rotate the anchorage, the control means being connected to the anchorage.

4. A model as claimed in claim 1, wherein the biasing means acts in opposition to a torque applied by the tension in the length of elastic material to members which are respectively connected to the anchorage and a support for the rotary propelling means, said members being pivotally connected together for limited pivotal movement between the first and second positions about an axis laterally offset from the length of elastic material.

5. A model as claimed in any one of claims 1 to 4, comprising a second control means which provides a second control surface and which is adapted for movement from a first to a second position thereby to actuate a second control action on the path of movement of the model and which is resiliently loaded into its first position by the motor force when the motor is fully wound, and a second biasing means loading the

second control means towards its second position against the motor force, the arrangement being such that as the motor runs down, the motor force reduces to such an extent that the second biasing means overcomes the effect of the motor force on the second control means and moves the second control means into its second position.

6. A model as claimed in claim 5 in combination with claim 4, wherein the second biasing means acts in opposition to a torque applied by the tension in the length of elastic material to members which are respectively connected to the anchorage and said support, said members of the second control means being pivotally connected together for limited pivotal movement between the first and second positions about an axis laterally offset from the length of elastic material.

7. A model as claimed in claim 5 in combination with claim 3 wherein the anchorage is capable of limited rotational movement between first and second positions about an axis laterally offset from the line of action of the tension in the elastic material, the motor force operating to bias the anchorage into said first position thereof, and the second control means being connected to partake of said rotational movement of the anchorage and the first and second positions of the second control means corresponding respectively to the first and second rotational positions of the anchorage.

8. A model as claimed in claim 4 in the form of a model aeroplane having a fuselage on which are mounted wings and a tail which provides tail planes and a rudder, wherein the propelling means comprises a rotary propeller and the elastic material extends between and is connected to the propeller and an anchorage adjacent the tail and wherein the fuselage comprises two parts hinged together end-to-end about an axis offset from the line of the strip for relative pivotal movement between first and second end positions relative to each other, the tension in the wound-up strip urging the fuselage parts into said first relative position, and a tension spring connected between anchorages on the first and second parts, which anchorages are offset from the line of the elastic material, said tension spring constituting the biasing means and urging the parts into said second relative position about said axis.

9. Apparatus as claimed in claim 8, wherein said axis is horizontal.

10. Apparatus as claimed in claim 8, wherein said axis is vertical.

11. Apparatus as claimed in any one of claims 8 to 10, wherein said hinge axis between the parts of the fuselage is disposed adjacent the propeller.

12. Apparatus as claimed in claim 6, comprising a model aeroplane having a fuselage on which are mounted wings and a tail which provides tail planes and a rudder, wherein the propelling means comprises a rotary propeller and the length of elastic material extends between and is connected to the propeller and an anchorage adjacent the tail, and wherein the fuselage comprises three parts hinged together end-to-end about two respective axes which are offset from the line of the elastic material, the relative pivotal movement of the two adjoining parts being between first and second end positions relative to each other, the tension in the wound-up strip urging each pair of two adjoining parts into their first relative position, and two tension springs constituting the first and second biasing means respectively which tension springs are engaged to urge the two adjoining parts of each respective part into their second end position relative to each other.

13. Apparatus as claimed in claim 2, comprising a model aeroplane having a fuselage on which are mounted wings and a tail which provides tail planes and a rudder, wherein the propelling means comprises a rotary propeller and the length of elastic material extends between and is connected to the propeller and an anchorage adjacent the tail, and wherein said movement of the anchorage operates cam means connected to actuate a rudder movement about a vertical axis and/or a tail plane movement about a horizontal axis.

14. A model aeroplane substantially as hereinbefore described with reference to and as illustrated in Figures 1 and 2, or Figure 3, Figure 4, Figure 5 or Figure 6 of the accompanying drawings.