A precleaner arrangement for separating a portion of entrained material from air flow air entering an engine air cleaner; the precleaner arrangement comprising: (a) a precleaner housing comprising a central hub and an outer ring surrounding the hub ; (b) at least a first flexible air deflection vane with a fixed portion secured to the precleaner housing and a deflectable portion ; the at least first flexible air deflection vane being positioned between the central hub and the outer ring , each flexible air deflection vane being secured to the central hub and outer ring at the fixed portion of each vane; (i) the deflectable portion including a curved section extending from the fixed portion and a tail section extending from the curved section ; (ii) the fixed portion of the first air deflection vane defining an upper terminal edge ; and (iii) the deflectable portion of the first air deflection vane defining a perimeter including an inner side edge oriented adjacent to the central hub and an outer side edge oriented adjacent to the outer ring and a lower terminal edge bridging the inner and outer side edges; each of the inner and outer side edges extending from the fixed portion ; the tail section defining the lower terminal edge ; characterized in that (iv) the tail section has a variable thickness in a radial direction being greatest at the inner side edge and decreasing in thickness to the outer side edge . (a) a precleaner housing comprising a central hub and an outer ring surrounding the hub ; (b) at least a first flexible air deflection vane with a fixed portion secured to the precleaner housing and a deflectable portion ; the at least first flexible air deflection vane being positioned between the central hub and the outer ring , each flexible air deflection vane being secured to the central hub and outer ring at the fixed portion of each vane; (i) the deflectable portion including a curved section extending from the fixed portion and a tail section extending from the curved section ; (ii) the fixed portion of the first air deflection vane defining an upper terminal edge ; and (iii) the deflectable portion of the first air deflection vane defining a perimeter including an inner side edge oriented adjacent to the central hub and an outer side edge oriented adjacent to the outer ring and a lower terminal edge bridging the inner and outer side edges; each of the inner and outer side edges extending from the fixed portion ; the tail section defining the lower terminal edge ; characterized in that (iv) the tail section has a variable thickness in a radial direction being greatest at the inner side edge and decreasing in thickness to the outer side edge . (i) the deflectable portion including a curved section extending from the fixed portion and a tail section extending from the curved section ; (ii) the fixed portion of the first air deflection vane defining an upper terminal edge ; and (iii) the deflectable portion of the first air deflection vane defining a perimeter including an inner side edge oriented adjacent to the central hub and an outer side edge oriented adjacent to the outer ring and a lower terminal edge bridging the inner and outer side edges; each of the inner and outer side edges extending from the fixed portion ; the tail section defining the lower terminal edge ; characterized in that (iv) the tail section has a variable thickness in a radial direction being greatest at the inner side edge and decreasing in thickness to the outer side edge . <EOS>