Coating reduces engine wear in unmanned aircraft

Dean Palmer takes a look at a coating originally developed for motorsport applications which is now being used to protect rotary engines in unmanned air vehicles

A coating originally developed for Formula One and other motorsport engines is also being used for the rotary engines in most of the world's unmanned air vehicles (UAVs). A leading supplier of rotary engines for UAVs in the UK is UAV Engines (UEL), which is using Apticote Ceramic 2000, a metal matrix coating system specially developed for high performance automotive engine applications. UEL manufactures a range of lightweight rotary engines from 20bhp up to 120bhp, with a patented air-cooled design that makes them more compact and helps to reduce mechanical friction and improve fuel consumption. The coating, which was developed by Gloucester-based coatings specialist Poeton Industries, is used to add high wear resistance and low friction properties to the trochoidal bores of the rotary engine housings. A plasma sprayed coating of Apticote 800 is also applied to reduce wear in the engine seal tracks. A spokesman at UEL said the company was using Poeton's coating expertise to improve engine operating characteristics under extreme climatic conditions. "This work has successfully resulted in the introduction of a number of product enhancements with additional improvements nearing the end of the development phase." On the choice of coating, UEL said its engineers were "convinced that Apticote Ceramic 2000 was making a significant contribution to the performance of the engines, which have successfully passed a 150-hour severe duty FAR 33-type ground durability test, setting new standards for small, ultra-lightweight unmanned aircraft engines." The UK has a significant technology lead in unmanned air vehicles (UAVs), with the world market for UAVs now estimated to be around £2 billion per year, with an annual growth rate of 12.5%. The greatest benefit of UAVs is that they are 'pilotless', so there is no risk of human life, there are no constraints on design or size, they can be ultra lightweight and can be continuously operated for more than 100 hours. UAVs are not only used by the aerospace and defence industries, but also for civil projects such as agriculture, police surveillance, border control, traffic and weather monitoring.