Overview
There are presently two principle alternatives to engine bleed air Ice Protection on mid to large size aircraft; these are known as ‘electro-expulsive’ low power and ‘electro-thermal’ systems.
Whilst electro-thermal systems can perform very successfully when provided with adequate electrical power, an electro-expulsive system can be highly energy efficient and therefore extremely attractive on platforms where generator sizing is critical or less power is available for the ice protection system.
Neither system in isolation necessarily offers an ideal IPS solution for all future wing types. The purpose of this integration study was therefore not only to investigate the integration of the IPS technologies to a Wing Slat but moreover to conceive the most appropriate combination of the technologies for Wing Slat ice protection. These ‘Hybrid’ systems had been used successfully on horizontal stabilisers on smaller aircraft types, but further work is required in the application to larger platforms and wings.
In addition to the CfP scope, GKN offered to integrate its own proven electro-thermal technology alongside the Associates’ electro-thermal and expulsive technologies to enhance the value of the integration activity and form a technology alliance to increase the probability of finding a successful solution.
In addition to functionality of the overall IPS the ‘actuation’ system aspects must be seamlessly integrated into the aircraft structure and electrical architecture. The current A320 slat was designed specifically to incorporate an engine bleed air IPS; therefore any change to this paradigm required a carefully controlled design and integration approach and thorough understanding of wing performance requirements together with structural design ability in metallic and composite materials.
The final project deliverable was a modified A320 Wing Slat incorporating a Hybrid Electrical Ice Protection System.
Funding
Results
Executive summary:
The SIEDIT project was based around the development of a hybrid wing ice protection system combining electromechanical and electrothermal ice protection systems into a unified system that uses the benefits of both systems. The intention was that the system runs as a de-ice system where the electrothermal system would generate the run-back ice, which would form over the electro-expulsive system and will be shed using the actuator once sufficient thickness has built up.
The challenges to be tackled in SIEDIT were based around the integration of the two sub-systems into a complete leading edge in an effective manner. The integration was demonstrated at a representative scale for testing in the National Aeronautics and Space Administration (NASA) Glenn Icing Research Tunnel on October 2012. The system was assessed against a number of performance criteria but had to meet certain technical requirements that are set by Airbus in order to generate a design that is realistic for future use. The top-level documents from Airbus drove the initial design decisions on the system sizing and performance criteria. The rest of the system design was driven by the requirements generated from the respective subsystems and the space envelope dictated by the wind tunnel model. The full set of requirements for the initial design work had been highlighted in Deliverable 1 'DEV / R / 8522 / 304 - SIEDIT Design Requirements Document'. This document established the key drivers from the customer perspective and framed the technical problem-solving discussions around the means of meeting them with the two sub-systems.