GB2201931A - Ornithopters - Google Patents

Abstract

A flapping wing aircraft has wings which flap, in unison, about hinges 24 and are also free to move in another plane about a transverse hinge 21. Springs or/and other elastic means exert some control over both movements and the reciprocating drive rod 33 also tends to actuate the wing movement in pitch as well as in flapping. The wings produce thrust during the downstroke by tipping or pitching of the wings relative to the high pitch-inertia body. A toggle link assembly 42, 43 with torsion bars 52 and drive rod 33 with centre line aft of transverse hinge line 21 are employed. Authoritative aileron control is obtained by a linkage with a floating arm pivot (85 86) (Fig 3) and links (83 84) which together compensate for the effects of wing flapping and wing pitching on the transmission of pilotage movements to the aileron control surfaces. Each wing may be fitted with a flapping outer wing which is power operated to flap to a greater angle relative to the body than the inner wing and this outer portion may be fitted with a plain flap spring biased to the central position. <IMAGE>

Description

ELAPPING-WING AIRCRAFT This invention relates to aircraft of the flapping wing type and particularly but not exelusively to power driven flapping wing airoraft in which the entire forward propulsive thrust is derived from the cyclic powered flapping of the wings, without the use of an airscrew, Jet or other forward propulsion means0 Whilst the invention is primarily applicable te aircraft in which the flapping of the wings is driven by a prime mover motor such as a petrol engine, the possibility of its being aptlied tO.-a man powered aircraft is not excluded.

In flapping wing aircraft, the forward propulsion thrust on the aircraft is derived from the reaction to the rearward propulsion of masses of ambient air caused by the flapping motion of the aircraft wings. Lift is produced mainly by the upward vertical components of air pressure on the wings produced aerodynamically by the airflow past the airfoil section wings of the forwardly propelled aircraft, Just as in conventional fixed wing aircraft.

According to the present invention in its broadest concept a flapping wing aircraft has at least one pair of wings each hinged adjacent to its root to the body of the aircraft about a fore-andaft hinge axis, and driving means coupled to the wings and operable to drive them in an up-and-down angular movement in unison, about their hinges, i.e. a flapping motion, so that they propel the aircraft forwardly whilst providing aerodynamic lift.

The forward propulsive thrust on the aircraft is derived from the reaction to the rearward displacement of masses of ambient air caused by the flapping action of the wings; lift is produced mainly by the upward vertical compoaents of air pressure produced aerodynamically by the airflow past the airfoil-section wings as they flap or whilst they are stationary in a gliding mode.

The present invention may be characterised by any one of the following important optional features, or by one or more combinations of two or more of the said features:- (a) Each wing of the pair is spring-biassed angularly about its flapping hinge axis in the sense tending to pivot it in the direction of its downward flapping stroke by spring means, which thus tends to assist the drivlhg~msans during the downward flapping strokes of the wings and to oppose the driving means, so as to be recharged, during the upward flapping strokes.

(b) The spring biassing means of paragraph (a) aforesaid comprises torsion bar spring means acting between each wing of the pair and the body of the aircraft, or joined at the end which is located remotely from the wing convection to each other so that they each balance the torsion forces of the other, ( although other spring biassing arrangemenk such as one or more floating springs acting directly between the two wings of the or each pair of wings can be envisaged).

(c) The driving means for producing the flapping movements of each wing of the pair may include a longitudinally-reciprocating driving shaft connected by a toggle linkage to the wing at a point radially spaced from its flapping hinge axis.

(d) Thieving means set forth in paragraph (c) aforesaid comprises a sin e ltudinally-reciprocating shaft coupled to both wings by a double toggle linkage so that its longitudinai reciprocation causes both wings of the pair to flap in uiisoi.

(e) The longitudinally-recprocating shaft set forth ii para (c) or in paragraph {d) or paragraph (e) aforesaid, and is so arranged that it will be stressed to the greatest degree at the point ii each flapping cycle where We toggle mechanism provides the lowest mechanical advantage, for example @t a dead centre position or the reciprocating shaft correspOndiag to the start of a downward flapping stroke.

(g) The two wings of the pair are also hinged about a coramon tilting axis transverse to the fore-and-aft direction and are arranged to undergo a cyclic variation in their angular attitudes about the said transverse axis during the flapping motion,such that the trailing edge of each wing rises relatively to its leading edge during the downward flapping stroke of the wing and falls during the upstroke.In this way; effective rearward displacement of air and forward thrust on the aircraft can be achieved, without excessive cyclical rise and fall of the body of the aircraft during the flapping motion. Duril1g each downward flapping stroke the angle of incidence to each wing to the airflow passing it becomes increased due to the downward movement of the wing, increasing the lift, and vise-versa during the up-stroke, but this effect is compensated by the cyclic tiltingof the wings which produce compensatory variations in the angle of incidence and in the lift, thus tending to reduce or eliminate cyclic changes in the lift imposed on the body of the aircraft during the flapping of the wings.Additional hinges may be fitted close to the wing tip typically at l or Z metres frem it and an increased flapping angle may be obtained by v actuating wires inside the wing operating from the movement of the toggle linkage at the wing root attachment. Thus outer wigs flapping through a larger angle than the main wings may be fitted with seperate spring-biassed plain flaps.

(h) The transverse tilting axis of the wings refered to in paragraph (g) aforesaid is located in front df the centre of pressure of each wing and the cyclic tilting of the wings during flapping is controlled and limited by further spring-biassing means which acts on the wings to resiliently oppose their angular displacement in each direction from a central position. In this wa7 the compensating tilting of the wings during the flapping cycle may be achieved automatically in flight, the increased lift during the downward flapping stroke causing a reduction in the angle of incidence and vise versa in the up-stroke.

(i) The transverse tilting axis of the wings As additionally located in front of the longditudinally-reciprocating shaft refered to in paragraph (d). When the wings are in the downward flapping stroke the force in the shaft which induces this movement of the wing will be in the sense to achieve compensating titing of the wing as described in paragraph (h) aforesaid and which will add to the effect of the increased lift and provide more immediate compensation being the result of the moving force rather than the movement itself.

By this means by suitably positioning the hinge refered to as the tilting axis in paragraph (h) above relative to the centre of pressure and relative to the shaft refered to in paragraph (d) aforesaid the response of the tilting of the wing during the flapping cycle can be adjusted to an optimum pattern in regard to rate and timing.

In conjunction with the features set forth in paragraph (h) aforesaid, spring-loaded flaps are provided along the wing span for the pupose of augmenting the lift-equalising action of the cyclic tilting of the wings. Some of these flaps may comprise ailerons for roll control.

(k) A manual control of the cyclic tilting movement of the wings during flapping may be provided, superimposed on the resilient control by the further erring biassing means as set forth in paragraph (h) aforesaid.

(1) Each wing of the pair may be hinged to the body of the aircraft about its fore-and-aft flapping axis by means of bearings carried by a flexibly-deforsable mounting structure attatched to the aircraft body, the mounting structure being constructed and arranged to deform, e.g. resiliently under the wing loadings experi.enced in flight to the extent limited by the engagement of the bearings of the hinge pins, or other rigid members carried by the wing, against abutments provided by stiffer structure carried by the aircraft body. This enables the wing hinge bearings to be designed to resist only limited wing loadings in flight, higher wing loadings.Lmposed by turbulence or manteavring being accoscodatedby the deformation of the flexible structure until the hinge pins or said other parts bear against the stiffer structure and provide the necessary reactive loading without overstressing the wing hinge bearings themselves.

The invention may be carried into practice in various ways, but one specific embodiment thereof will now be described by way of example and with reference to the accompanying purely diagramatic drawings, in which; Figure 1 shows diagrammatically the wing mounting bracket and toggle arrangement with the drive linkage at the roots of the two wings of a flapping wing monoplane as viewed from the front in the direction of the fore-and-aft axis of the plane; Figure 2 shows the monoplane of figure 1 diagramatically in side elevation; Figure 3 is a diagram of the aileron control mechanism; Figure 4 is a frontal view generally similar to figure 1 but on a larger scale and somewhat simplified, but showing also the tranverse hinge mounting arrangement for the wing mounting bracket on the aircraft fuselage and the outer wing hinge and cable or rod connections.

Figure 5 is a view in side elevation on a larger scale than figure, 2 and showing further details of the hinge and spring arrangements for the wings.

In the illustrated embodiment, a monoplane aircraft 10 shown in side view in figure 2 comprises a fuselage 11, a pair of flapping wings 12,12 mounted above the fuselage by mea4* Of a transversely-hinged flexible mounting bracket 13 of aluminium alloy, an i.c. engine 14 for driving the aircraft by flapping the wings 12,12 and the usual tail/ruddcr 15 and elevator fins 16.

The flexible mounting bracket 13 is resiliently mounted on a tranverse shift bar 17 by means of spigot pins 18 and extending through rubber bushes 19 carried by the bracket 13 as shown in figure 1. If the transvere shift bar is not fitted,as in some cases it will not be nescessary, then the flexible bracket will carry the hinge .brackets 20,20. These hinge brackets are shown in figure 1 to be mounted on the shift bar but in figure 4 they are mounted on the flexible mounting bracket. The bar 17, when flitted, is substantially rigid in comparison with the flexible bracket 13 and maybe fitted with hinge brackets 20,ego or may not.The hinge brackets 20,"20 are connection to similar brackets 21, 21 so that the wing assembly is pivotally mounted on the fuselage so that it can tilt about a tilting hinge axis 21A transverse to the fore and aft direction of the aircraft together with the wing mounting bracket 13 and the wings 12, 12 carried by it.

6aek wing 1E is hinges to ;he bracket 13 about a flapping hinge axis 22 (figure 4) extending in the for-and-aft direction of the aircraft adJacent to the wing root near the level of the underside of the wing section. As shown ia figure 2, each flapping hinge comprises a hinge pin fournalled in a ball or roller bearing 24 mounted in an aperture in a lug 25 of the mounting bracket 13. Each of the hinge pins 23 also extends through an oversize clearance hole 26 in the stiff clearance bar 17 so as to permit a limited amount of flexible deformation of She bracket under the wing loading before the hinge pin abuts against the edge of the clearance hole 26 and tranfers the wing loading to the stiff bar 17.This enables the bearings 24 to be designed to withstand only limited wing loadings in servos, up to say 1.5 to 3.0g. In the event of greater w loadings such as values of 3.3g due to manoeuvring or even greater values up to 3.8g or 4.5g which may be caused by conditions of great turbulence, the excess load will be transfered to the stiff bar 17 by the hinge pins 23.

The stiff bar 17 and its clearance holes 26 and spigots 18, and the rubber bushes 19, have been omitted in figure 4 for the' sake of clarity.

The engine 14 which might for example be a petrol engine of about 200 cc capacity, drives a crank wheel 30 through a belt or chain drive 31, as best shown in figure 4, to rotate the crank 32 at about 1 cycle per second. One end of the drive shaft 33 is coupled by a "big eid bearing 34 to the crank 32 so that the shaft 33 reciprocates longitudinally in the manner of a connecting rod. The upper end of the connecting rod is connected by bearing 36 to a double toggle linkage generally indicated at 40 in figures 1 and 4. The toggle linkage 40 comprises a bell crank toggle lever 41 pivotally conected by a central bearing 42 to a straight toggle link 43 corresponding in length and altitude to the longer arm 44 of the bell crank lever 41.The shorter arm 45 of the bell crank toggle lever is pivotally connected at its outer end to the small end bearing 36. lhe outer ends or the longer arm 44 and the toggle links 43 are pivotally connected respectively to the outer ends of the pair of identical radius aras 46 and respectively to the ends of a pair of identical second toggle links 48 by respective bearings 49. The other ends of the second toggle links 48 are pivotally connected by bearings 50 to the wings 12 at points equally spaced from and above the wing flapping bearing 22. The inner ends of the two raddius axes 46 are pivoted to the mounting bracket 13 on opposite sides of the shaft 33, by means of bearings 51 whose inner bearing members comprise the ends of a pair of torsion bar springs 52.The dimensions and arrangements of the various parts are such that the double toggle linkage 40 is symetrical on either side of a line joining the centre of the central toggle bearing 42 to the centre of the crank wheel 30, and it will be apparent that the longitudinal reciprocation of the drive shaft 33 by the crank mechanism 30, 32 driven by the engine 14 will cause the toggle mechanism 40 to rotate the two wings 12 through equal small angles about their flapping ayos 22 to produce the required cyclic flapping of the wings at a frequency corresponding to the speed of rotation of the crank wheel 30 e.g. 1 cycle per second. The top-dead-centre position of the crank mechanism 30,32 corresponds to slightly less travel than that possible before the toggle mechanism reaches the top dead centre position as indicated in brocken lines at 40A in figure 4. with the links 48,43 and arm 44 all in alignment.

The leading edges of the two torsion bar springs 52 are journalled in the bearings 51 carried by the mounting brackets 13,' and ar^.rigidly secured to each razzs arm 46. The rear end of each torsion bar 52 is rigidly secured by key-way to bracket 53 to a single beam which connects both brackets 53 so that torsion from one torsion bar reacts torsion from the other torsion bar each acting on the same beam in opooing directions.

The two torsion bar springs are prestressed torsionally in opposite senses such that each applies a biasing torque to its associated radius arm, and hence to the wing 12 connected thereto by the respective link 48, in the sense tending to produce a downward flapping stroke of the respective wing 12 about its hinge axis 22.

With this arrangement the biassing torque produced by each torsion bar spring 52 will be at its' maximum at the bottom dead centre position of the crank mechanism 30, 32 at which time the mechanical advantage of the toggle mechanism 40 is at its lowest value. During the ensueing upward stroke of the shaft 33, the torsion springs 52 will assist the mechanical drive to force the wings through their downward flappizg stroke, in opposition to the aerodynamic lift being exerted on them by the relatively moving airflow past them.As the crank melanism approaches its top dead centre position, it once again approaches its position of maximum mechanical advantage, and likewise the toggle mechanism 40 increases its mechanical advantage to the maximum at top dead centre, thus offsetting the progressive reduction in the spring-biassing torque from the torsion bar springs 52 as they unwind.

During the subsequent half cycle in which the shaft 33 moves downwards against the spring biassing,recharging the springs 52, tte wings will be driven through their upward flapping strokes aided by the aerodynamic lift.eserted on -them, The entire sub-assembly of the flexible mounting bracket 13 and the two wings 12 attached to it by the hinges 24 and the toggle mechanism 40, is itself pivotally mounted by means of the hinges 21 of the brackets 20, for tilting movement about the transverse tilting hinge axis 21A. The two wings 12 are interconnected st their roots near their trailing edges bX a cross linked bracket 60 to which is attached a spring loaded plunger or wire 61 which extends downwardly.In the case of a plunger rod being used as shown at figure 5, the rod passes through an aperture in an aachorage bracket 62 on the fuselage; a pair of springs 63, 64 act in opposition to one another between the fixed bracket 62 and the respective upper and lower collars 66,67 carried by the plunger rod 61 resiliently in a centralised position, but to allow the plunger rod , and the trailing edges of the wings 12 attached to it to rise and fall against the resilient forces of the springs b3,64 tending to return them to the centralised position. Thus the wings, witn the nounting bracket 13,, can tilt in unison upwardly and downwardly to a liited extent against tile action of tee springs 63,64 tending to recentrali them.Provision is made in t..e articulation of te crank and connecting rod drive to the toggle mechanism 40 to accommodate tnis tilting emotion.

The shaft 35 passes close to re transverse ninge olA so tnat changes in centre to centre distance due to the tilting action willbe small and can readily due accommouateu.

The spring loadea plunger 61 may be replaced or aumented by wires attached to springs 96,97. The springs shown in figure 5 as compression springs may convenlantly be tension springs which are placed anywhere that is convenient in the length of the wire. Two wires are required, an upper and a lower wire, figure 5 dotted, the upper wire being joined to the bracket 61 and being stretched upwards to a fuselage pulley situated above bracket 61 and then passing ever fuselage pulleys to connect with one end of its tension spring.The other end of this tension spring is connected to another wire which may be connected to a pilotage control in the reach of the pilot of the aircraft so that he can alter the tension in the spring as the need arises0 The lower wire is connected to its tension spring and the other end of this spring may also be connected to a pilotage control and arranged so that a single pilots action will tighten or relax the tensions in beth the upper wire spring and the lower wire spring.

This spring loaded tilting arrangement for the wings enables them to tilt cyclically automatically about the transverse axis 21A in response to the cyclic variation of air pressure. acting-on the wings and also to a lesser degree in response to the reciprocating force in the crank mechanism and the drive shaft 33. The centre of pressure of each wing and in the downward stroke the upward thrust from the drive shaft 33 tilt the wing forward with the trailing edge moving upwardly producing a forward component of lift which directed forward along the flight path provides a component to counter the normal air drag of the aircraft and provide sustained flight and climb.

In the upstroke the effect is different in that the drive shaft force is reversed and the lift on the wings tends to reduce due to the effect ot the upward motion of the wing through the air. Both these effects tend to increase the wing angle by lowering the wing trailing edge so increasing the angle of incidence and the wing lift and thus compensating for the wing motion. By means of the spring resisted cyclic tilting of the wings produced by pressure changes during the flapping motion, cyclic variations in the resultant aerodynamic lift imposed on the flapping wings and transmitted by them to the fuselage, can be eliminated or substantially reduced thus avoiding cyclic vertical movements of the fuselage as the wings flap. The cyclic tilting of the wings in flight can be controled or overrides by the pilot through the manually-controlled adjustment to the damping and the initial loading of the springs 63,64. or in the case of the use of wire8, aprings 96,9? by means of wires 95,96 attached to lever 71 to control initial tension.

In order to provide to pilot with a control to lock the the wings against any cyclic tilting of the wings during flapping,.. both the plunger rod 61 and the wires. 94,95 and springs 96,9? and wires 98,99 may be brought to connect with lever 71i A hinged joint incorporated in the wing separates the outer wing from the nain wing at a pout 1 or 2 metres from the wing tip, figure 4 shows the joint and its connections in front elevation with the hinge axis 109 paralel to the main wing hinge axis 22 but these axes may be arranged in any random relative orientation.Figure 4, for the sake of clarity, shows only one outer wing assembly, the outer wings ol both sides of the aircraft and the driving means are symetrical.

The outer wings are designed to flap in unison with the main wings but to travel to a larger angle in the upward stroke and in the downward stroke although the relative values of these angles may be fixed to suit aircraft general configuration considerations such as the need to limit the dorn stroke to enhance ground clearance on take off.

Brackets 46 and 111 on figure 4 are rigidly fastened to the torsion springs 52 and oscillate with each cycle of the flapping motion; wire8 108 are attatched to brackets 111 and pass over pulley wheels 110 and along and inside the main wing to be joined by pin jointed means to outer wing hinge bracket 107 each wire having an offset from the hinge line which is of correct magnitude to provide a turning moment about the hinge and a movement through the required outer wing flapping angle. Thus as brackets 111 oscillate with the torsion springs 52 the outer wing 112 also move through an angle of rotation about the centre oi hinge 109 relative to the hinge anchorages on the main wings 12.In the outer wing to augment the thrust caused by the flapping through a large angle trailing edge plain flaps may be fitted which are constrained in trailing angle by a system of springs and damping. Such flaps are preferably balanced about their hinge lines with mass balance weights as is normal for many light aircraft. These flaps will augment the automatic lift-equalioing effect by increasing the cyclic tilting effect at and near the wing tips.

The automatic lift-equalising effect produced by the resiliently opposed cyclic tilting of the flapping wings can be augmented if desired by the provision of spring-loaded flaps along the wing spaa and by the use of spring-loaded ailerons for roll control. In the usual case the ailerons may be mechanically connected so that they are pushed into a downwardly deflected position by the movement of the aileron control linkage when the downward stroke is almost complete. The effect of this mechanical deflection of the ailerons near the end of the flapping stroke is to produce a lift force pulse at the time when the ring is required to change its direction of movement from the downward stroke to the upward stroke. The lift force pulse will then assist this cange of direction of movement.The same arrangement may, if desired be incorporated at the end of the upstroke although the torsion bar spring is also assisting the change of direction of movement at the completion of the up-stroke.

Figure 3 shows diagrammatically and in front elevation a suitable linkage for aileron control. Differentially-operating.control rods 80,81 leading from the pilots control column extend upwardly and are attached to symetrically placed centre-pivoted levers each leading to wing aileron control levers 87,88 through a nearly vertical link, so oriented that the wing can pivot about the hinges 22,23 without substantially moving the wing aileron control levers 87,88.

The aforesaid centrally pivoted levers shown as 85,86 on figure 3 are attached by their central pivot to another rod-lever system 180,101 whose object is to maintain the alignment of the central pivot of lever 85,86 between the end joint of link83,84 and the end joint of rod 80,81.

The rod lever system is itself pivoted at its outer end on a pin 102,103 which is fixed in the centre wing structure shown as 106 on figure 3 which may be part of the centre wing structure 25 on figure 1. The inner end of the rod-lever consists of rods4, 105 which are freely pin-jointed at their ends to levers 100,101 and to the fuselage at one or more pins 82.

The linkage for the aileron control can be arranged in differing configurations and it gives a adjustable flexibility to the position of the aileron tria with either both ailerons down or both ailerons up, during the flapping cycle. For reasons of energy absorbtion at the extreme positions of each stroke it is desirable to trim rr.omentarily the ailerons down at the end of the down-stroke and up at the end of the up-stroke and throughout the stroke to maintain the differential movement of the ailerons which is necessary for control of the aircraft in the rolling mode.The rod-lever system together with the links 83,84, witch can be adjusted in length during the developement process, provide a floating hinge point for levers 85,86 which will move to automatically adjust position to allow for rise and fall of the wing structure relative to the fuselage. This rise and fall is seen clearly as a feature of moct aileron control systems fitted to a wing fuselage arrangement such as 'hat shown at figure 2 when the control linkage is fitted between 1/3 and 1/2 of the wing chord distance iroin bue leading edge, and the wing is tilting about hinge point 21.

To the outer ends of the cross-bar of each T-shaped lever 87 or 88 are connected a pair of control rods or wires 89,90 extending along the length of each wing and operatively connected to the aileron. Spring means shown diagrammatically at 91 is incorporated in one of rhe cables or rods 89,90 to provide the aforesaid spring loading of the associated aileron, alowing the ailerons to ce deflected cyclically Dy tne air pressure variations produced by flapping the wings.

rotations of the two centre pivoted levers 85, 86 in' clockwise direction will cause rotations of the two T-shaped levers 87,88 in opposite directions and hence a differential operation on the two wings for control purposes.

An advantage of the power-driven aircraft described and: illustrated is that it derives its entire forward propulsive thrust from the reaction to the rearward propulsion of air masses by the flapping action of the wings and does not require any airscrew such as the fixed pitch airs crew which is the usual forward propulsion means for a very light aircraft. Pitch control mechanism for the propeller blades of a light aircraft is expansive, and if an aircraft with a fixed pitch airscrew whose blades cannot be feathered, is flown in the gliding mode with the engine idling or switched off, the air-flow-rotated airscrew will impose a sustantial drag on the glide flight. With the present flapping-wing aircraft there is no airscrew to produce drag, and the craft can be flown with the engine idling or stopped, and the wings flapping very slowly or stationary, in an extremely efficient gliding mode.

Claims (9)

CLAIMS.

1. A flapping wing aircraft comprising wings which are hinged about a fore and aft hinge axis and a body or fuselage containing a power means, pilotage means and an elastic or spring system arranged to extend and compress co-operative with the flapping of the wings.

2. A flapping wing aircraft as claimed in claim 1 wherein the elastic and spring means oppose the movement of the wings in such a way and with sufficient force as to reduce the velocity of flapping motion at the end of each upward and downward movement to a low value.

3. A flapping wing aircraft as claimed in claim 1 and claim 2 comprising two wings each with an inner and an outer portion; the outer portions mounted on further hinges also with the hinge axis closely to the fore and aft direction. The outer portion is connected to the power means so that it moves through a larger flapping angle relative to the body, than the inner portion.

4. A flapping aircraft asclaimed in claim 1 claim 2 and claim 3 wherein the flapping actuator driver rod centre line passes aft of the main wing mounting pin or pins.

5. A flapping wing aircraft as claimed in claim 1 claim 2 and claim wherein the main wing mounting pin or pins joining the wings to the body are a hinge with a hinge axis accross the body along a line parallel to a line drawn from one wing tip to the other wing tip, both wings being free to rotate in unison around this hinge line in a pitching sense relative to the body.

6. A flapping wing aircraft as claimed in claim 1 claim 2 claim 4 and claim 5 wherein the rotation of the wings in the pitching sense is resisted by the provision of elastic and/or spring means.

7. A flapping wing aircraft as claimed in claim claim 2 claim 4 claim 5 and claim"6 wherein the elastic and/or spring means resisting the movement of the wings relative to the body in the pitching sense are adjustable in tension and stiffness by the pilotage control.

8. A flapping wing aircraft as claimed in any previous claim wherein the aileron control is routed through a system of rods and levers which, by their intrinsic geometry, maintain pilotage control of the ailerons at any position and rate of movement of the wings during the flapping and pitching cycles.

9. A flapping wing aircraft substantially as described herein with reference to figures 1 to 5 of the accompanying drawings.