GB2030879A - A toy aircraft - Google Patents

Abstract

A toy aircraft has the form of a helicopter or gyrocopter with a body 10, tailplane 13 extending from the body and a bladed rotor 19, 20 mounted for free rotation about an axis extending upwardly above the body. Each blade 20 of the rotor has a negative pitch and the body has tether attachment means 26, the attachment means being so positioned on the body that in flight a tether or tethers coupled thereto maintains the attitude of the craft such that the rotor is rotated by wind impinging on the blades so providing lift to maintain the craft in flight. <IMAGE>

Description

SPECIFICATION A toy aircraft This invention relates to a toy aircraft and more particularly a toy helicopter or gyrocopter.

Toy aircraft of different forms are known and widely used by children of all ages. These aircraft can range from the extremely simple balsa wood gliders having a planarfuselagewith main wing and tailplane to the more sophisticated radio or tether controlled powered flight aircraft. The latter are extremely complex in construction with associated high cost whilst the former not having these factors are of much inferior performance and lack any great amusement value. Between these two extremes, it could be said, fall the wind powered craft such as kites. These are normally cheap to construct and with modern constructions can be extremely enjoyable to fly as they can be made to soar and perform spectacular movements.

The aim of the present invention is to provide a toy aircraft in the form of a helicopter or gyrocopter which is easy and economical to construct and is wind powered so that no separate prime mover such as an engine is required.

Broadly the invention consists of a toy aircraft having the form of a helicopter or gyrocopter with a body, tailplane extending therefrom and a bladed rotor mounted for free rotation about an axis extending upwardly above said body, characterised in the each blade of said rotor has a negative pitch and the body has tether attachment means, the attachment means being so positioned on the body that in flight a tether or tethers coupled thereto maintains the attitude of the craft such that the rotor is rotated by wind impinging on the blades so providing liftto maintain the craft in flight.

In more fully describing the invention reference will be made to the accompanying drawings in which: Figure lisa side view of the helicopter according to the invention, Figure 2 is a plan view, Figure 3 is a front elevation, Figure 4 is a cross section of the blade, and Figure 5 is a cross section through a portion of the blade mounting.

The body 10 can be constructed from a suitable material but it is envisaged that a plastics material will be the most suitable for weight, strength and manufacturing convenience. The body 10 includes a seat 11 on which a model of a pilot can be placed.

The body sides 12 can include openings 16 as shown to assist in weight reduction and distribution as well as adding to the aesthetic appeal of the craft. A tail plane member 13 projects from the rear of the body as shown and includes a small wing 14 at its outer extremity. This wing 14 is provided to assist the flight stability of the craft and can, if required, be adjustable in relation to its radial projection from the circular cross-section tailplane member 13. Usually tailplane 13 extends so as to be parallel to the ground, i.e. horizontal.

A support frame 15 extends from the upper portion of the back of seat 11 and forms part of body 10.

Once more openings 16 are formed in the support frame 15. Positioned atop of support frame 15 is a cross piece 17 from which projects a spigot 18. This spigot 18 is fixedly mounted and can be formed either integrally with cross piece 17 or supported thereby. Rotatably mounted at the outer end of spigot 18 is a blade attachment member 19 which is elongate and fixedly mounts at each end a blade 20.

A ball or needle race bearing B is mounted by said member 19 and this bearing engages on the end of the spigot 18. Bearing B is retained on spigot 18 by a bolt or stud 18' extending upwardly through or from spigot 18 and held in place by nut 29. This mounting arrangement permits free rotation of the rotor about the axis of shaft 18.

Each blade 20 has a profile substantially as shown in Figure 4 which is a normal aerofoil section but preferably with a small chamfer 21 at the lower leading edge thereof. The blades 20 are mounted with a negative pitch which for the example illustrated in the drawings is in the order of 2". This pitch is achieved by having the arm portions 19' of member 19 angled at an incline of 2" to a plane normal to the axis of spigot 18. As can be seen from Figures 1 and 2 member 19 includes a central portion 19" which houses bearing B. The arms 19' extending from portion 19" have a planar top surface with which the planar undersurface of blades 20 engage. As these top surfaces are each inclined at 2" as mentioned above the blades are pitched with the same angle.It will be appreciated that the arms are inclined in opposite direction Member 19 is preferably formed with blades 20 attached so causing the blades to "droop" slightly in a similar manner to a conventional helicopter or gyrocopter.

The blades 20 are held in place by a single fastening such as a small nut 30 and bolt 31 and additionally located by a raised dome portion 32 on arm 19' fitting into a similarly shaped recess 33 in the undersurface of the blade 20. Accordingly, blade 20 can fold back if during rotation of the rotor the blade comes in contact with a solid object or the like. This is achieved by the blade riding over dome 32 whilst pivotting about bolt 31.

The extreme outer end of each blade 20 is weighted. These weights can be a bullet shape slung from the undersurface of the blades or else areas of increased cross section as shown at 28 at each outer end of blades 20: These so formed weights 28 serve to increase the radius of gyration of the complete blade formed by the pair of blades 20. Without the weighted blade ends control of the craft is difficult if not impossible.

The body of the craft is completed with legs 24 which support skids 25 on which the craft stands when not in use as well as providing authenticity.

The attachment means can take the form of a hook or ring (not shown) mounted at the front of the body and located on the central longitudinal plane verticallythrough the body 10. Alternatively, openings 26 (or hooks, rings or the like) are provided at each forward end of sides 12. A separate tether (not shown) is attached through each of openings 26 so the craft can be flown by two people (pilot and copilot). If the craft is to be flown by one person the separate tethers can be attached at their free ends to a single rigid elongate control bar. Preferably in such an arrangement, two tethers extend from each opening 26 with one of each pair attached to respective ends of the bar and the remaining pair of tethers attached centrally in the length of the bar.

As shown in Figure 1 the attachment openings 26 have a predetermined relationship to the plane of blades 20 and a line L drawn through the point of mounting of the member 19 to shaft or spigot 18 and opening 26. This relationship is also related to the centre of gravity of the craft and in the disclosed embodiment line L is at an angle of about 40 -45 to the horizontal and the plane of the blades is at an angle of about 13s15" to the horizontal. These ranges give the tolerance to fly properly.

In use the tethers are attached as aforementioned and can be in the form of a string or wire which are tied or clipped through openings 26. The craft is then held into the wind with the nose tilted upwardly so the plane of the rotor is angled to the wind. This angle is preferably in the order of 60". The rotor is then spun by hand and will accelerate due to the wind impinging thereon. As the rotor accelerates the angle is reduced to around 10 . Self rotation continues with the craft lifting from the operator's hand when rotational velocity of the rotor is sufficient.

During flight correct attitude of the craft is maintained by the tether reactions acting through openings 26 ensuring the attitude is such that the angle of the plane of rotation of the blades 20 to the wind impinging thereon causes the blades to continue rotating and thus maintain the craft aloft. Flight continues until the operator "lands" the craft or the wind drops to a speed less than necessary to maintain self rotation of the blades. By increasing/decreasing tension of the respective tethers the craft can be moved from left to right or vice versa.

It is apparent that the relationship between the attachment means and blade plane of rotation is important to the craft flying correctly. The negative pitch of the blades cause a vacuum to be created which lifts the craft and the weighted ends of the blade render the craft more controllable. With these factors correctly incorporated in the finished craft self rotation of the wind powered blade is ensured.

As a safety precaution other than the blades folding back (as previously described) a buffer member 34 can be provided at the outer end of each blade.

This member 34 is in the form of a tear shaped (see dotted detail in Figure 3) planar piece of resilient material such as rubber or soft plastics. An aperture (not shown) is formed in the member to allow it to be passed over the end of the blade and into engagement in a peripheral groove formed in the blade.

Accordingly, if the blade should accidently come in contact with a person the buffer member34 will absorb much of the impact. The impact forces will also be dissipated by the blade folding back as previously described.

The resultant toy is most spectacular in flight in that it not only flies in the same manner as a helicopter but has the same noise created by blade movement. Considerable height can be obtained by paying out the tether and simulated forward flight can be achieved by movement on the part of the operator.

Claims (21)

1. Atoy aircraft having the form of a helicopter or gyrocopter with a body, tailplane extending therefrom and a bladed rotor mounted for free rotation about an axis extending upwardly above said body, characterised in that each blade of said rotor has a negative pitch and the body has tether attachment means, the attachment means being so positioned on the body that in flight a tether or tethers coupled thereto maintains the attitude of the craft such that the rotor is rotated by wind impinging on the blades so providing liftto maintain the craft in flight.

2. An aircraft as claimed in claim 1 wherein the outer end of each blade is weighted.

3. An aircraft as claimed in claim 1 or 2 wherein an imaginary line drawn between said attachment means and the intersection of the rotor with said axis is at an angle in the range of substantially 40 to 450 to the horizontal.

4. An aircraft as claimed in claim 3 wherein the plane of the rotor is at an angle in the range of substantially 40 to 450 to the horizontal.

5. An aircraft as claimed in any one of claims 2,3 and 4 wherein each blade has an aerofoil section with the lower leading edge thereof formed with a small chamfer.

6. An aircraft as claimed in any one of claims 2,3 and 4 wherein each blade has an aerofoil section.

7. An aircraft as claimed in claim 5 or 6 wherein the flat undersurface of each blade is mounted so as to lie at an angle to a plane normal to said axis.

8. An aircraft as claimed in claim 7 wherein said angle to the normal plane is substantially 2".

9. An aircraft as claimed in any one of the preceding claims wherein the tailplane includes a wing which extends to one side of the central longitudinal plane of the body.

10. An aircraft as claimed in claim 9 wherein said wing extends at substantially 90" to said central longitudinal plane.

11. An aircraft as claimed in any one of the preceding claims wherein said blades are coupled together by a mounting member, said mounting member having a ball or needle race bearing positioned equidistant from the mounted ends of the blades, said bearing being supported by mounting means on said body.

12. An aircraft as claimed in any one of the preceding claims wherein said attachment means are a pair of spaced apart openings, hooks, rings or the like mountings attached at the forward end of the body.

13. An aircraft as claimed in any one of the preceding claims wherein said attachment means is a single opening, hook, ring or the like mounted situated centrally at the forward end of the body.

14. An aircraft as claimed in any one of the preceding claims wherein said body is supported on legs which mount a pair of parallel skids.

15. An aircraft as claimed in any one of the preceding claims wherein said body, rotor blades and tailplane are constructed from a plastics material.

16. An aircraft as claimed in claim 9 wherein the wing is mounted by a boom extending rearwardly from said body, the radial direction of projection of said wing being adjustable.

17. An aircraft as claimed in claim 2 wherein each blade is formed of a plastics material and has an area of increased cross-section at or adjacent the free end to form said weight.

18. An aircraft as claimed in any one of the preceding claims wherein each blade is connected to a mounting rotatably mounted on said body by a single fastening, the blade being located in place by a projection on said plate or mounting engaging in a recess in the respective mounting or blade.

19. An aircraft as claimed in any one of the preceding claims wherein a buffer member is mounted at or adjacent the outer end of each blade.

20. Atoy aircraft substantially as herein described with reference to and as illustrated by the accompanying drawings.

21. Any novel feature or combination of features herein described.