GB2229685A - Aircraft wheels with rotating means - Google Patents

Abstract

A series of vanes (several alternative designs are described) each vane being mounted upon a simple rotating axis upon an aircraft wheel or attached trim, which will automatically open at the lower 180 degrees part of an aircraft wheel and automatically close at the upper 180 degrees part of the wheel under the influence of the slipstream, and which will cause a greater air resistance on the bottom half of the aircraft wheel and a much smaller resistance at the top half of the wheel. This will cause the aircraft wheel to rotate in sympathetic motion to the aircraft flight when landing upon the runway and greatly reduce or eliminate the burn and friction suffered by an aircraft's tyres when first in contact with the runway, and also assist in a smoother landing for the aircraft. <IMAGE>

Description

Technical Field Aircraft Wheels Rotating Anti-Friction Device This invention relates to a series of devices interspaced around the face of an aircraft wheel and which may be attached or moulded or contained in a separate trim upon the wheel.

The devices will be in the shape of a rounded concaved vane type of windtrapping device as shown preferably in Figure 5, but may be any suitable shape that will give air resistance when in the raised position. The basic technical feature is that of a surface that will give air resistance when in the raised position and incur the least air resistance when in the collapsed position.

The invention is designed to cause aircraft wheel rotation when the undercarriage is lowered by causing air resistance at the lower part of the wheel and less resistance at the top part of the wheel, causing the wheel to rotate in sympathy with the aircraft direction and at the approximate ground speed of the aircraft when landing and reducing the friction upon the tyre when coming into contact with the runway.

Background Considerable tyre wear on an aircraft wheel tyres is normally caused by first contact with the runway upon landing as the aircraft wheel is not synchronised to the ground landing speed of the aircraft.

This extensive wear and tear upon tyres can be greatly reduced if the aircraft wheel can be rotated in the aircraft forward direction at approximately the ground landing speed. This would also reduce the risk of burst tyres and assist a smoother landing. The invention should save considerable costs on very expensive aircraft tyres and reduce maintenance costs.

Essential Technical Features According to the present invention there is one of several types of devices as per Figures 4-9 which effect wind trapping results at the lower part of an aircraft wheel and sustaining a smaller air resistance at the higher part of the wheel, causing the wheel to rotate in the aircraft landing direction at approximately the same ground speed, thus reducing the friction that is normally suffered by the tyre when contacting the ground.

The basic principle of the invention is to cause sufficient air resistance by a protuberance that is raised automatically at the lower part of the wheel and which will also automatically collapse in a near flat position when at the higher part of the wheel.The object is to cause rotation of the wheel and tyre in a close matching landing speed of the aircraft.

It is preferable for the device to aerodynamically to cause the maximum air resistance at the lower part of the aircraft wheel and the least resistance at the higher part of the wheel, and the particular design adopted for a particular aircraft should therefore reflect this consideration. A typical design is shown in Figure 5 and also in Figure 8, where the front air collecting surface is concaved and the back surface is convexed and which latter allows the airflow to pass over its rounded surface with the least resistance.

Each type of aircraft and wheel must have a tailor made design individually as aircraft landing speeds and wheels vary to a considerable degree.

The vanes or other types of protuberances should be suitably interspaced around the wheel face.

The design should also take into account that where the compartment for the undercarriage is restricted, the convex back of each device should lend itself to be folded into the collapsed position by contact with the roof of the compartment when the undercarriage is raised.

At the time of take-off by the aircraft there should be little resistance to the forward speed by the device as its 'bite' into the airstream should be in sympathy with the airflow.

Each device is on a rotating axis with a suitable back stop allowing the device to stand erect under air pressure at the bottom half of the wheel, and collapsing forward upon its axis at the higher part of the wheel when the air flow acts upon the back of the device, thus giving a maximum and minimum air pressure where desired.This movement should be automatic in its function being acted upon by the consequent airstream upon the surfaces of the front concaved face and the convexed back half.A moderate spring attached would act as a damping influence in the forward and backwards movements.

As centrifugal force will also act upon the devices when the wheel rotates, the design of each device must compensate for this. Whilst the centrifugal force will not matter when the devices are in the lower position of the wheel as the C.F.

will only assist the devices to remain erect in that position at the time when it is desired they should be erect, it is of considerable benefit to the desired operation that when the devices are in the higher position of the wheel when they are required to lay flat to the wheel surface, for the centrifugal force to be counter-balanced to prevent it from raising the devices into an upright position.

The design of the device should therefore include a counter-balancing weighted lip at the trailing end of the device with preferably an axis above the bottom of the device so that the centrifugal force will act upon each part of the device above and below the axis thus causing an equal force on both sides of the axis resulting in a negating or counter-balancing effect.

See Figure 5 t43 and Figure 8 t43 for a typical design to achieve this effect. The design should therefore be such that the weight of the lip below the axis,including additional counterbalancing weights where required) should match the weight of the device above the axis. The centre point of gravity of each part of the device above and below the axis may be taken as the calculated point representing the concentrated weight for the purposes of calculating the C.F. effect.The principles of leverage , i.e. the product of forceEweight) and distance from the fulcrum,then apply in calculating the desired counter-balancing weight ratios required for each part on either side of the axis, as the centrifugal force will act equally upon the two sides of the axis given that the weights according to the law of leverage are adhered to.

It should be noted that the effects of centrifugal force in general apply as follows: (A) Mass or weight give a directly proportional C.F.

at a given speed, i.e. doubling of the weight will double the C.F.

(B) The radius of the weight from the centre is also directly proportional in C.F. effect, i.e. doubling of the radius will double the C.F.

(C) The speed of the wheel gives a directly proportion al C.F. effect to the square of the speed,i.e. if the speed is doubled the C.F. effect is increased four-fold.

Under (A) if the principles of leverage are followed as suggested then the counter-balancing weights each side of the axis will be of equal C.F. effect.

(B) will not normally apply as the counter-balancing weights will be at equal distances from the centre of the wheel, unless it is desired to vary the counter-balancing weights of the trailing lip Figure 5 t43 at a different radius as it may be adv antageous, for example,to place the greatest counter-balancing weights at a larger radius.

(C) Should not apply as obviously all the apparatus will be on the same wheel at the same speed.

In order to reduce the effects of centrifugal force the devices should preferably be made largely in a sufficiently strong but lightweight material, possibly plastic or aluminium.

The trailing lip part of the device should preferably be so designed so that its edge will be as close to the wheel surface as possible, probably of a curved shape, so that the airflow upon it when in the collapsed position will cause the least air resistance. An alternative design would be to raise the lip section proud of the main surface of the device and secured by suitable brackets, hinges or rods,etc. to the main surface, and thus allowing the air flow to pgswithout resistance between the aperture allowed between the main surface and the lip rear section of the device.See Figure 8 93 and Figure 9 (9) Alternatively the air flow acting under the rear lip may be directed through an aperture in the wheel surface beneath the lip, or through the bottom surface of a trim where used, so that the air flow may be directed away from the lip without too much resistance.

Other suitable well known engineering designs may be used to reduce air resistance upon the back part of the device when it is in the collapsed position, e.g. sliding brackets or sleeves interlocking to allow movement one way only,etc. The main intent is of course, to allow the devices to alternatively stand erect at the bottom half of the wheel and to lay flat to the wheel when at the higher part of the wheel.

Specific embodiments of the invention will now be described by way of examples with reference to the accompanying drawings in which: - Figure 4 Shows a schematic view of the aircraft wheel with a plan outline of the devices interspaced at suggested intervals( which may be increased or decreased in number according to needs).

An outline of the rear lip where required (1 BC) A typical vane or flange on a simple axis Figure 5 Shows a schematic view of the device with attached rear lip to the main surface with suitable stops for the erect position.

Figure 6 Shows a side view of Figure 5 of the main surface and rear lip only Figure 7 Shows a side view of the main surface and rear lip with axis hinges 5 and air flow direction Figure 8 Shows a schematic view of the device with aperture alternative between the main surface and the rear lip to allowing the air flow to pass without resist ance between the two.

Figure 9 Shows a side view of Figure 8 with the raised rear lip above the line of the main surface and which allows the air flow to pass through the aperture shown in figure 8 (9) when in the collapsed position.

Note that 5 is an outline only of the securing axis shown in Figure 8 (5), the air flow passing between 4 s 2 (Figure 93 as in Figure 8 (9) In Figure 4 the outline devices shown are open and erect at 2 A at the bottom half of the wheel. The air flow is resisted by the vanes in this position and causes the wheel to rotate compatably with the aircraft direction.The erect position is maintained by suitable stops.

At 1B the vanes are collapsed by the airflow as they will now be positioned with their backs to the air flow and will therefore rotate upon their axis and be forced to collapse to the wheel surface area, the rounded backs also reducing the air resistance.

There is also shown a typical outline of the vanes with a simple axis (no rear lip 3 in the open erect and collapsed positions.

One example of the added weighted rear lip, when required, is shown in outline, see 1BC on aircraft wheel.

Figure 5 shows the vane apparatus with the weighted rear lip 4 to compensate for centrifugal force. The swivel axis 5 allows the upright and collapsed movements. 6 are the axis lines of movements about 5. 8 refers to the damping springs, 2 is the main concaved surface, 7 refers to the stops for the upright position. 3 shows the overall vane device which is in one piece with a suitable opening for the axis.

Figure 6 shows an outline of Figure 5.

In the open position, the airflow will impinge upon the surface of the vane at 2 causing the vane to move the wheel backwards untill the device reaches the top half of the wheel when the airflow will act upon the the rear of 2 causing it to collapse to the surface.In this position,any air flow under the rear lip may be channelled under the surface through an aperture the wheel.

In Figures 7,8 & 9 the action of the forces as described for Figure 5 are the same except that the aperture design is shown at 9 allowing the airflow to pass between the main vane surface and the weighted rear lip thus reducing air resistance.

The two parts of the device, the main surface and the rear lip, are secured together by suitable connecting rods or brackets (10).

Figure 9 shows a side view of the main surface 2, the raised lip 4, the axis 5 tin outline) and the open aperture 9 for the free airflow between the main surface an d the lip, either over the convex back of the main surface and/or under an aperture in the Wheel face or trim attachment when this is used to contain the whole device.

To summarise, the device should be a design of a wind collecting vane, flange,etc. that is raised by the airflow to an upright position when facing into the airstream and which will then provide an air resistance against its face causing the pressure to force the device and the attached wheel backwards thus rotating the wheel in a synchronised direction to the aircraft's forward flight, and calculated to rotate the wheel at approximately the same landing speed on the ground as the aircraft. So thereby reducing the friction normally incured when the wheel first touches the runway. When the device is facing away from the airstream, the back of the device will be forced by the airflow to collapse down to the surface of the wheel or attached trim where the later is used, the upright and collapsing movements permitted by the means of an axis.

The action of centrifugal force upon the devices at the top part of the wheel is neutralised by counter-weights about an axis that will effectively achieve an equal weight force each side of the axis(which will act as the Fulcrum) extra weight compensating for any disparity in distance from the Fulcrum, as it will very probably not be desirable to have the same width from the axis for both the main surface and the rear lip.

There are several methods for reducing the air resistance on the back of the device where the rear weighted lip is used and three such methods have been described.The convex back of the main surface should easily lend itself to being conveniently folded flat when contacting the roof of the undercarriage chamber when the undercarriage is raised. The forward speed of the aircraft at take-off will not suffer any air resistance from the devices as the 'bite' of the device will be commensurate with the forward air flow.

As an illustration of the wheel rotation required, the basic date only being used, the following formula applies: Ground landing speed say 120 miles per hour Wheel Diameter " 4 Feet Then 2FI R = Wheel circumference = 12.56Ft.

5280 Ft. X 120 = 10,560 Ft. per minute . 12.56 60 = 841 RPM Wheel rotation

Claims (11)

1. CLAIMS 1. A series of aerodynamically designed vanes preferably vertically concaved on the inner side and convexed on the outer side, secured to the side of an aircraft wheel by a simple freely rotating axis with a stop positioned so that the vanes may only be raised to an upright vertical position to the surface of the aircraft wheel and at a 90 degrees angle to the side of the aircraft wheel automatically under pressure from the airstream when facing into the airstream at the lower 180 degrees part of the wheel. The number of devices may vary according to the type of aircraft wheel/aircraft and may be set either radially to the aircraft wheel axis or at a tangent to the axis as in Figure 10.

   There may also be provided a raised lip at the leading top edge of the vane facing the airstream with its concaved face in order to assist its elevation to the upright position and also assist in collapsing the vane to the horizontal position when its convexed back is presented to the airstream at the 180 degrees higher part of the aircraft wheel.
2. 2. A series of vanes as in Claim 1 but with an extended weighted lip beyond the simple axis as described in Claim 1 and to act as a compensating weight against centrifugal force particularly when the devices are set at a tangent to the aircraft wheel axis.
3. 3. A series of vanes as claimed in Claim 1 and Claim 2 but with the extended lip beyond the simple axis as in Claim 2 and which said extended weighted lip is positioned proud of the surface of the back of the main vane and which is secured by suitable crossbars, etc. and which will then allow airflow to pass between the extended raised lip and the back of the main vane surface when the vane is in the collapsed position at the 180 degrees higher part of the aircraft wheel, as in Figures 8/9.
4. 4. A series of vanes as claimed in Claim 1 or Claim 2 or Claim 3, which may be placed in a desired sequence on one or both sides of the aircraft wheel.
5. 5. A series of vanes as claimed in Claims 1,2,3, and 4 whereby said vanes may be extended in length beyond the metal fabricated part of the aircraft wheel and thus extending to a distance up to the depth of the tyre sidewall.
6. 6. A series of vanes as claimed in Claims 1,2,3,4, and 5 wherein the concaved inner surface of the vanes have lateral crossbar protrusions to assist in the effectiveness of the air damming nature of the vanes.
7. 7. A series of vanes as claimed in Claims 1 to 6 which are attached or moulded to the metal structure of the aircraft wheel or contained on or in a trim fitment which may be secured to the aircraft wheel.
8. 8. A series of vanes as claimed in Claims 1 to 7 with a suitable damping spring shown by way of example in Figure 5(8) wherein the up and down movements of the vanes will be made smoother and also give minimal assistance in raising the vanes at the lower 180 degrees of the aircraft wheel whereby the airstream will act upon the slight aperture afforded by the vanes slightly raised by the damping spring,thus forcing the vanes upward to the erect position.
9. 9. A series of vanes as claimed in Claims 1 to 8 and to incorporate in their design a rounded or convexed shape on the outer or back of the vane to assist in the vanes being folded flat against the aircraft wheel wheel when the undercarriage is retracted and thus assist in the storage when the undercarriage storage compartment is restricted.
10. 10. A series of vanes as claimed in Claims 1 to 9 whereby an aperture in the aircraft wheel base, or the trim where used as described in Claim 7, and positioned closely behind the simple axis of the vane will permit the airflow to channel down the aperture in place of striking the back of the vane, notably in the instances where the vanes are also extended with the lip as particularly described in Claim 3.
11. 11. A series of vanes substantially as described in Claims 1 to 10 with reference to Figures 4 to 10 to cause rotation of an aircraft wheel in sympathetic direction to the aircraft forward speed when landing on the runway for the purposes of reducing burn on the aircraft tyres and assisting in a safer and smoother landing.