GB2353258A

GB2353258A - Aircraft wheel rotator

Info

Publication number: GB2353258A
Application number: GB9919275A
Authority: GB
Inventors: Simon Groves
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-08-17
Filing date: 1999-08-17
Publication date: 2001-02-21
Also published as: GB9919275D0

Abstract

The aircraft wheel rotator is connected to the landing gear of an aircraft and comprises a shroud plate 4, defining a diffuser 7, and vanes 5, attached to or forming part of a wheel rim 3. When the undercarriage is lowered, the shroud plate deflects the oncoming air over the vanes to cause the wheels to rotate. The speed of rotation can be adjusted by altering the position of the deflector plate. The position of the deflector plate and hence the speed of rotation of the wheels with respect to the oncoming air can be adjusted mechanically and locked in position. Alternatively, the position of the deflector plate can be altered automatically, and the wheel speed monitored and controlled so that speed of the periphery of the tyre is equal to the runway speed when landing.

Description

1 2353258 AIRCRAFT WHEEL ROTATOR.

This invention relates to a device that equalises the speed of the aircraft landing wheels with the speed of the runway prior to landing.

When aircraft land, their wheels are normally stationary prior to coming into contact with the runway. Upon contact with the runway, the wheels accelerate from rest, to runway speed very quickly. The force needed to accelerate the wheels from rest to runway speed relies on the friction between the runway and the wheel tyre. Aircraft tyres are usually made of a rubber compound. The heat generated by the friction between the stationary wheel and the moving runway during this period of rapid acceleration has a detrimental effect on the rubber tyres.

By bringing the speed of the wheel at or near to the speed of the runway prior to contact, the tyres will not be subjected to such rapid acceleration, ffiction, heating and deterioration. This will result in:

reduced tyre wear longer tyre life lower acceleration forces on the wheels smoother landings less rubber deposits (skid marks) on runways The aircraft wheel rotator utilises the air flowing past the wheels due to the forward motion of the aircraft and the resultant relative velocity between the air and the wheels as the aircraft approaches the runway. Landing speeds vary depending on the type of aircraft, but are typically between 100 and 200 miles per hour. The air flowing past the wheels is made to act on a series of vanes attached to the wheel rim. A shroud is fitted in order to divert the air on to the vanes. The action of the air on the vanes is to cause rotation of the wheel in the same direction as would occur once the wheels are in contact with the runway.

The shroud comprises a curved plate, with edge strips and a central, raised diffuser to give rigidity and to ensure that the required amount of air is deflected onto the vanes.

Depending on the type of landing wheel, be it single, double, fixed, retractable, and the landing speed of the aircraft, the design may vary slightly but the principle is the same in each case. The speed of wheel rotation is dependent on the angle of attack between the shroud and the air stream. This can be set manually during the installation of the shroud, whereby the shroud is locked in position to give a certain wheel speed for a certain air speed, or it can be adjustable.

By adjusting the angle of attack between the shroud and the air stream, the flow of air over the vanes can be increased or decreased to change the wheel speed accordingly. This allows for fine control of the wheel speed prior to landing. Wheel speed can be monitored, compared to ground speed, and the shroud adjusted to ensure that wheel speed and ground speed are equal prior to landing.

2- Figure 1 shows an isometric drawing of a typical twin wheel landing gear arrangement, with the wheel rotator in position.

Figure 2 is a front elevation.

Figure 3 is a sectional side elevation.

Figure 4 is an isometric drawing of the shroud.

Figure 5 is a side elevation of the shroud.

The wheel rotator comprises vanes 5 and the shroud plate 4. The vanes are attached to or form part of the wheel rim 3. The shroud is attached to the landing gear assembly 1 using lugs 10 and 11 on the back of the shroud.

Lugs 10 and 11 correspond to lugs 8 and 9 on the landing gear assembly. The holes in lugs 8 and 10 are coincidental and are pinned and free to rotate. Lugs 9 and 11 are connected via a link. The link can be adjusted and locked, or the link can be adjustable to permit movement of the shroud and fine control of wheel speed.

On the front of the shroud are edge strips 6 and a central diffuser 7. These act to give the plate rigidity, but also deflect the required amount of air flow over the vanes. The edge strips 6 are feathered towards the bottom of the shroud to allow the air to fall over the side of the shroud and onto the vanes. The central diffuser 7 deflects oncoming air towards the sides of the shroud and onto the vanes. Any loss of rigidity by reason of the feathering of the side plates is made up by the increase in section of the diffuser towards the bottom of the shroud.

The drawings show a typical twin wheel landing gear assembly. When the aircraft is approaching the runway and the landing gear is down, the air hitting the shroud plate 4 is deflected by the side plates 6 and the diffuser 7 onto the vanes 5. The effect is that more air hits the vanes at the bottom of the wheel rim 3 than at the top. This results in a turning moment which produces rotation.

Adjustment of the shroud angle, either manually or automatically, allows the tyres 2 to be at, or very near to the speed of the runway prior to touchdown.

For single wheel applications, a shroud is used which deflects the air flow in one direction only. The single shroud is half of the illustrated double shroud, being cut vertically down the middle, but with the addition of an edge strip above the diffuser to prevent too much of the air flow spilling over the outer edge of the shroud.

3

Claims

1. The aircraft wheel rotator rotates the aircraft wheels so that the periphery of the tyre is at or near the speed of the runway when the wheels make contact with the runway on landing.

2. The aircraft wheel rotator uses the forward motion of the aircraft through the air to rotate the wheels.

3. The speed of rotation can be adjusted and controlled.

4. The aircraft wheel rotator will reduce the amount of aircraft tyre wear that occurs on landing.

5. The aircraft wheel rotator will reduce the extent of tyre marks and deposits on runways.

6. The aircraft wheel rotator reduces the effect of the sudden acceleration of a non rotating wheel when it comes into contact with the runway on landing.

7. The aircraft wheel rotator as herein described and illustrated in the accompanying drawings.