Terms of Reference

The Transmissions Technical Activity Committee (TAC) is one of six Committees within the Aerospace Division which specialise in various aspects of the Aerospace Industry.

The following is a brief statement on the aims and activities of the Committee for which we are continually seeking people who could contribute to our activities by joining the Committee.

By definition Transmission is to convey power by a mechanism from one mechanical part to another. In Aerospace applications the aircraft engine power is utilised to drive in some applications a propeller, a prop-fan, or a helicopter rotor and to achieve this requires a mechanism which in this
instance is a transmission system. These systems primarily incorporate a Gearbox of some design together with appropriate shafting. In addition the engine power can be transmitted by means of a Power Take-Off Shaft to a Gearbox driving accessory equipment such as Electrical Generators and Hydraulic Pumps providing vital power for the control systems of a modern aircraft. Within the aircraft control systems further transmission systems incorporating gearboxes exist for the actuation of flight control surfaces such as leading and trailing edge flaps.

From this it can be seen that the Transmission System is a vital mechanism and demands innovative design to meet the weight criteria most important in modern aircraft, reliability to meet airworthiness
requirements, manufacturing techniques to satisfy cost targets, together with a product achieving a good maintainability standard thus reducing the cost of ownership for the ultimate customer.

To achieve these requirements the following technology is being employed, gear design and manufacture involving uprating of spur and helical involutes, spiral bevels and development of conformal gears. Successful development of materials and lubricants, component technology from bearings to sensors and airborne processors. The understanding of failure mechanisms and enhancement of health monitoring facilities, FMEA's and improved reliability data. Computer aided design techniques for deflections, stresses, heat transfer, dynamic behaviour and noise and finally improved test facilities.

A wide range of new technology developments are at hand to assist, some requiring research effort, but many requiring further development, among them high temperature steels, skeletal gearbox casings, metal matrix composites, oil specially formulated for aerospace gearboxes, optical sensors and data transmissions systems to reduce maintenance workload and scope for error.

So how can Technical Activity Committees contribute to the future? This contribution is by promoting principally through Seminars, dialogue between practitioners in all activities relating to Aerospace Power Transmissions, with the object of strengthening UK industry by: 

• Reviewing design methods and data; 
• Seeking common ground on the development of materials, lubricants, machine tools and processes and components; 
• Reviewing means of improving airworthiness; 
• Providing stimulus and direction to university research, undergraduate and postgraduate course material and projects; 
• Stimulating government funding authorities to provide continued support.

Chairman
Transmissions Technical Activity Committee