High Durability, Light Weight Bearings for Small Turbine Engines

The purpose of this project is to demonstrate the feasibility of using hydrodynamic air foil bearings (AFBs) or hybrid air foil bearings (HAFBs) with ultra-low friction, wear resistant and solid lubricant coatings to provide significant improvements in durability and cost reduction for small turbine engines for unmanned aerial vehicles. AFBs have simple construction, great service life, reduced maintenance and superior dynamic performance compared to traditional bearings such as rolling element bearings. More importantly, AFB systems are oil-free and expected to reduce total engine weight by up to 30%. In addition to hydrodynamic AFBs, HAFBs with increased load capacity at low speeds and enhanced rotordynamic stability will also be evaluated for infinite life. Acrees advanced tribological coatings provide superior wear characteristics and substantial improvement over Teflon or polyimide type coatings that are typically used on AFBs. The coatings are made of highly lubricious and extremely durable materials that reduce frictional heating and are resistant to scuffing and galling. The coatings are applied using Acrees Energetic Deposition Process which yields a highly dense and smooth film that does not require post-deposition grinding or polishing.