GB2120621A - Aircraft wing - Google Patents

Abstract

A wing 10 for a microlight aircraft is cut from a block of foamed plastics material, e.g. polystyrene, axial channels 18 are cut to receive spars 12 and the foamed plastics wing members 14 are adhered to transverse ribs to form the wing. The wings may be assembled into a biplane configuration having two sets of wings mounted on a fuselage and braced by means of a flying wire, a landing wire, and a strut, in which the strut is selectively hingeable to allow rapid disassembly of the wing. The wing may be covered with a skin of woven synthetic material. <IMAGE>

Description

SPECIFICATION Wings This invention relates to an improved wing construction and in particular to an aircraft embodying such a construction.

Recently there has been a great deal of interest in the field of so-called 'Microlight' aircraft, most of which have been developed from hang gliders by the addition of a small engine and propellor.

Provided that the weight of microlight aircraft is below certain limits the stringent regulations governing the flying of normal aircraft do not apply to them and this brings microlight aircraft within the reach of many people for whom conventional aviation is too expensive. Furthermore, the light and open construction of microlight aircraft, in many ways similar to the early days of aircraft development but incorporating modern technology, is very appealing to many people who may feel that modern aviation is too clinical and devoid of much of the enjoyment of the pioneer days.

As already mentioned most of the microlight aircraft currently available are, in effect, modified, hang-gliders and they therefore have canvass or other flexible fabric wings. The invention seeks to provide a wing construction which is light and strong but is also rigid to enable the construction of a microlight aircraft having rigid wings.

According to one aspect of the present invention there is provided an aeroplane wing which comprises one or more axial struts having at least one transverse rib mounted thereon the or each rib being attached to a wing body member of low density plastics material.

Preferably, the low density plastics material is a foamed plastics material, for example foamed polystyrene, polyurethane, or the like. Wing body members may be cut from a solid biock of such foam material using a hot wire cutting method into shaped portions having the required aerofoil section. Axial channels may then cut out of the wing body members allowing insertion of the or each strut therein where it may be held in place for example by means of adhesive.

The transverse ribs may be of a suitable material such as wood or metal and may be fixed to the body members for example by means of adhesive. The ribs have suitable holes through which the axial strut may pass. The strut may be of any suitable material which combines strength with lightness, and is preferably a metal tube.

According to another aspect of the present invention there is provided a microlight biplane which comprises two sets of rigid wings mounted on a fuselage and braced by means of a flying wire, a landing wire, and a strut, in which the strut is selectively hingeable to allow rapid disassembly of the wings.

Preferably, the rigid wings are constructed in accordance with the first aspect of the invention discussed hereinabove.

The invention will be described further, by way of example, with reference to accompanying drawings, in which: Fig. 1 is a plan view of a wing constructed in accordance with the invention; Fig. 2 is a sectional view, on an enlarged scale, taken along line A-A in figure 1; and Fig. 3 is a partial front elevational view of an aircraft construction in accordance with the invention.

Referring to the drawings, a wing 10 constructed in accordance with the invention comprises a pair of axially directed struts 1 2 of thin gauge aluminium tubing, preferably type HT30 high tensile stainless drawn aluminium tube, mounted on which are wing body members 14 as described more fully hereinafter. The wing members 14 are reinforced by means of plywood ribs 16 having the same shape as the wing section.

The wing body members 14 are preferably cut, for example by means of conventional hot wire cutting techniques, from blocks of foamed polystyrene into the aerofoil section illustrated in figure 2. Channels 1 8 are cut in each body member 1 4 to receive the spars 1 2. The ribs 1 6 are glued or otherwise adhered to the side faces of the body members 14 so that the circular sections of the channels 1 8 align with one another and with the corresponding holes in the rib 1 6 thus allowing the spars 12 to be pushed through the assembly the length of the wing 10. Once the spars 12 are in place, adhesive is poured into the channels 1 8 and the spars 12 rotated in order to distribute the adhesive evenly within the channels.

Following this, plug portions 20 of polystyrene are replaced in the channels 18 thereby sealing them. Once the adhesive has hardened a very strong but light rigid wing results. -If desired, as illustrated in figure 2, leading and trailing edges of the wings may be reinforced with other materials, for example balsa wood. The projecting ends of spars 12 may then be fixed to the aeroplane fuselage.

Referring now more particularly figure 3, one side of a biplane construction is illustrated in which two wings constructed as described above are attached by means of a spar 12 to an aircraft fuselage 22 by means of brackets 24 and releasable pins 26. The wings are braced by means of a strut 28 and tension cables 30 and 32 referred to as the flying wire and landing wire respectively. The strut 28 is formed in two parts which are hinged together at 34. The hinge 34 may be prevented from operating by means of a restraint tube 36 which fits over the hinged portion 34 and maintains the strut in a rigid non hinging condition.When it is desired to dissassemble, the aircraft, e.g. for transport on a truck or trailer, the restraint tube 36 may be moved in the direction shown by the arrow in figure 3 until it is clear of the hinge 34 which allows the strut 28 to hinge thus releasing the tension on the flying wire 30 and the landing wire 32 which, in turn, allows the pins 26 to be released and the wings to be removed from the aircraft. This construction enables very rapid assembly and disassembly of the aircraft for land transport.

The aircraft constructed in accordance with the invention will normally be provided with a tail plane and rudder which may be of similar construction to the wings. Where controlled movement is required, as in the case of the rudder and ailerons, one of the spars 12 may act as the pivot point for the movement of a suitable cut out portion of the wing profile. For example, in the tail plane, the main spar doubles as a hinge and the ribs 1 6 are provided with nylon bearings so that the main body and ribs of the tailplane section can pivot with respect to the spar. Naturally this case the spar is not adhered to the body members or ribs with adhesive.

If it is desired to reduce drag on any of the tubular sections of the aircraft fairings may be provided. A preferred form of fairing may be constructed by taking a sheet of plywood scoring a line down the middle enabling the plywood to 'hinge' about the line, bending both sides of the ply about the tube and fixing the free ends together. By aligning the plywood so that the major axis lies in the direction of travel of the aircraft a streamline shape is given to the tube which reduces drag. Fairings made in this manner can be fitted to any of the wing or fuselage struts without removing them from the aircraft.

When it is necessary to connect to any tube forming a strut or spar in an aircraft constructed in accordance with the invention it is preferred to insert within the tube a length of nylon rod substantially filling the tube in the area where a hole is to be made. After drilling, a bolt may be fixed to the tube and tightened, the nylon rod helping distribute the load and prevent flattening or other distortion of the tube.

In certain cases it may be preferred to strengthen a wing constructed in accordance with the invention by giving it a fabric skin. One preferred form of fabric skin uses woven synthetic fabric capable of heat shrinkage. The fabric is placed over the wing section or other part to be covered, its free ends stitched together, and subjected to heat which causes it to shrink and grip the wing tightly.

Claims (13)

1. An aeroplane wing which comprises one or more axial struts having at least one transverse rib mounted thereon, the or each rib being attached to a wing body member of low density plastics material.

2. A wing as claimed in claim 1 in which the plastics material is foamed polystyrene, foamed polyurethane or the like.

3. A wing as claimed in either of claims 1 or 2 in which the ribs are of wood or metal and are fixed to the body members by means of adhesive.

4. A wing as claimed in any of claims 1 to 3 in which one or more axial struts pass through the ribs.

5. A wing as claimed in claim 4 in which the struts are metal tubes.

6. A method of making a wing according to claim 1 which comprises cutting wing body members from a block of plastics material, cutting axial channels to receive struts, adhering the body members to ribs to form the wing, and placing struts in the axial channels.

7. A microlight biplane which comprises two sets of rigid wings mounted on a fuselage and braced by means of a flying wire, a landing wire, and a'strut, in which the strut is selectively hingeable to allow rapid disassembly of the wings.

8. A biplane as claimed in claim 7 having wings as claimed in any of claims 1 to 6.

9. A biplane as claimed in either of claims 7 or 8 in which drag is reduced on tubular sections of the fuselage by providing fairings formed by taking a piece of plywood, soring a hinge line in the plywood enabling it to bend about the hinge, bending both sides of the ply about the tube, and fixing the free ends together.

10. A biplane as claimed in any of claims 7 to 9 having tubular structural members which, at positions where they are attached by bolts to other members, are filled with lengths of plastics material rod to distribute the load and Drevent distortion of the tube.

11. A wing as claimed in any of claims 1 to 6 in which a skin of heat shrinkable fabric is positioned over the assembled wing, the free ends of the fabric secured, and the fabric heat shrunk so as to grip the wing tightly.

12. A wing substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

13. A biplane substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.