GB2356839A - Motor used to rotate an aircraft wheel prior to landing - Google Patents

Abstract

A motor 4 is fitted to the wheel hub 3 of an aircraft and is used to rotate the wheel 2 prior to landing so that, on contact with the ground, the wheel speed is matched to the ground speed and skidding, leading to tyre wear, is reduced. The motor 4 uses a compressed air source, taken from an existing on board compressor, fed through a high pressure air feed line 7. A programmable logic controller receives inputs from a number of sensors, including a wheel rotation speed sensor 6, and automatically controls the flow rate of compressed air fed to the motor via a motorised valve 5. In a further embodiment, the motor 4 can be reversed to assist with braking after the wheel 2 has made contact with the ground.

Description

2356839 1/4.

AIRCRAFT WHEEL MOTOR This invention is of a means of rotating the wheels of an aircraft in flight.

The landing gear of an aircraft has numerous tyred wheels.

When gear is lowered prior to landing, these wheels are allowed to rotate freely until braking becomes neccesary.

The disadvantage of this practise is that, upon contact with the runway, the tyres suffer wear due to skid. This skid being caused by the requirement of the wheels to almost instantaneously obtain an appropriate number of revolutions consistant with ground speed, having previously been static, or almost.

Accordingly, this invention provides a means of driving aircraft wheels up to a speed which exactly matches that required for a no skid contact for a given speed over ground during final approach.

This may be achieved with various motor types, but here is described probably the most efficient arrangement.

A specific embodiment of the invention is here described with reference to the accompanying drawings in which:- 2/4.

Figure 1 shows a plan view of wheel and drive assembly as seen from the rear.

Figure 2 shows rear view of wheel and drive assembly in angled perspective.

Figure 3 shows block diagram of electronic control system for motor speed. Essentially a Programmable Logic Controller, P.L.C.

Ref. Fig.1 & 2 showing one part of an aircraft landing gear assembly where 1 is the tyre, 2 is the wheel, 3 is the hub, 4 is the air turbine motor within the rear of wheel 2 which could also be mounted as a smaller unit behind the hub 3 and geared to wheel 2, 5 is the compressed air control valve, 6 is the wheel rotation sensor, 7 is the high pressure air feed, and 8 is part of the existing brake assembly supply. it has not been possible to show here, the motor exhaust, but this could be directed to brake friction surfaces where cooling would be enhanced.

Ref. Fig.3 showing a programmable logic control where 1 is the P.L.C., 2 is the wheel rotation sensor input, 3 is speed over ground input data, 4 is a gear down detect input, to prevent motor run in gear up position, 5 is ground proximity detect input, 6 is control output to valve 5 in Figs. 1 & 2, 7 is an output to braking system where wheel overspeed is sensed, 8 is a possible output to reverse motor and assist braking on landing. This control system is automatic in selection via ground proximity detection, and fully automatic in operation with a failsafe to free rotation.

3/4.

Claims (4)

1 The addition to an aircraft wheel unit of a relatively small motor the speed of which is accurately controllable.

2 The wheel motor as claimed in 1 would use a compressed air source taken from an existing on board compressor such as is used for cabin pressurisation at altitude but available at ground level.

3 The wheel motor as claimed in 1 is controlled by a motorised inlet valve.

4 The valve as claimed in 3 has its flow rate determined by the output from an automatic system based on a programmable logic controller.

The P. L. C. as claimed in 4 is automatic in operation upon final approach to land, via the sequence Input 4, gear down enable.

Input 5, ground proximity enable.

Input 3, airspeed monitor on.

Input 2, wheel r.p.m. monitor on.

Output 6, airflow on or off when sum / differenence is detected on inputs 2 & 3.

Output 7, to brakes is on if input 2 becomes excessive.

Output 8, to reverse can be enabled on ground contact to assist braking.