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Civil aircraft protection against ice


The ice physics investigations have resulted in a very much better understanding of the physical properties of ice which will ultimately greatly assist the development of new ice protection and detection systems. The pilot programme has also enabled specialised techniques and facilities to be developed which will provide a sound basis for further developments in the knowledge of ice physics.

The study of a section of an accretion can reveal some of the history behind the formation of the ice. The trajectory of the iced up structure through the air, the temperature and the icing conditions and the way these vary, all leave recognisable features in the microstructure of the ice. These features are permanent enough to enable practical recovery, storage and transportation of the ice, providing suitable conditions are maintained.

The adhesion of ice to different materials varies significantly. The performance of a mechanical de-icer is influenced by the degree of ice adhesion, so the careful selection of surface material for de-icers will enhance their effectiveness.

The presence of ice may be detected by dielectric means, both at very low frequencies and in the microwave domain. The sensitivity of the techniques suggests potential to detect low levels of airfoil contamination, and more localised thicker accretions.

The use of thermal imaging techniques for ice surface temperature measurement is very practical. Lightweight equipment has the sensitivity and flexibility to provide invaluable data for heat transfer studies to improve ice accretion modelling approximations, and to help relate this to the observed structure and properties of ice.

A basis exists for the complete design of an impulsive de-icing system with a high probability of good performance without recourse to a lengthy iterative design and testing. Considerable potential exists to engineer the structures and materials involved in electro-impulsive de-icers to obtain better performance than has been achieved to date.
CAPRI is a pilot programme comprising a number of tasks which address both fundamental and technical aspects of aircraft ice protection.

During the initial phases of the programme, experimental and theoretical work on the mechanics and physics of ice and water will be undertaken in order to provide an improved understanding of the basics and to assess the potential of various concepts. These include microwave heating, advanced electrical, mechanical and electromechanical, ice phobic and fluid based systems. To complement this work an assessment of the ice protection requirements of aircraft of advanced aerodynamic performance will be made.

Following the preliminary fundamental phase of the investigation 2 potential systems will be selected for development and testing. The data available at this stage of the work will ensure that the design of the 2 systems can proceed without an extended period of development.

The 2 trial systems will be tested in an icing tunnel and their performance examined critically in the light of the theoretical and fundamental aspects involved. The consortium will, at this stage, have a consolidated understanding of the basic considerations and will be in a strong position to make further developments beyond the scope of the pilot programme.

Funding Scheme

CSC - Cost-sharing contracts


British Aerospace Defence Ltd
Warton Aerodrome
PR4 1AX Preston
United Kingdom

Participants (9)

Alenia Aerospazio - Un'Azienda Finmeccanica SpA
Viale Dell'aeronautica
80038 Pomigliano D'arco - Napoli
Aérospatiale Société Nationale Industrielle SA
37 Boulevard De Montmorency
75781 Paris
Rond-point Des Champs-elysees - Marcel Dassault 9
Fokker Aircraft BV
1100 AE Amsterdam
Lucas Aerospace Ltd
United Kingdom
Stafford Road Fordhouses
WV10 7EH Wolverhampton
Messerschmitt-Bölkow-Blohm GmbH (MBB)
81611 München
4 Dublin
University of Patras
Panepistimioupolis Rion
26500 Patras
Università degli Studi di Napoli Federico II
Piazzale V. Tecchio 80
80125 Napoli