A raincap precleaner comprising: (a) a sleeve (34; 122) having a periphery, said sleeve being constructed for mounting on a vertically arranged air intake stack and having an air intake flow region for delivering intake air to the stack; (b) a cover (32; 121) comprising a top portion (44; 132) having annular circumference and a depending flange portion (46; 133) extending from the annular circumference of the top portion, the cover being arranged relative to the sleeve to provide a precleaner area (38; 125) and a precleaned air chamber (66; 132a); (c) wherein the flange portion and the sleeve provide an annular area within the precleaner area, and wherein the annular area extends circumferentially around the sleeve; (d) a precleaner assembly (36; 124) provided circumferentially extending around the periphery of the sleeve (34; 122) and received in the annular area in the precleaner area (38; 125) so that environmental air flows through the precleaner assembly and into the precleaned air chamber, and from the precleaned air chamber into the air intake flow region; characterised in that, (e) said precleaner assembly (36; 124) comprises a panel (72; 146) of inertial separators (70; 140), said panel comprising an arrangement of inertial separators (70; 140) extending from a first wall (76; 142) to a second wall (78; 144) of the panel (72; 146); (f) said panel (72; 146) of inertial separators (70; 140) surrounds entirely said sleeve (34; 122) along said periphery thereof, and (g) said precleaner assembly comprises a scavenge chamber (80; 148) which is in communication with a scavenge outlet (42; 149) of the raincap precleaner (30; 120). (a) a sleeve (34; 122) having a periphery, said sleeve being constructed for mounting on a vertically arranged air intake stack and having an air intake flow region for delivering intake air to the stack; (b) a cover (32; 121) comprising a top portion (44; 132) having annular circumference and a depending flange portion (46; 133) extending from the annular circumference of the top portion, the cover being arranged relative to the sleeve to provide a precleaner area (38; 125) and a precleaned air chamber (66; 132a); (c) wherein the flange portion and the sleeve provide an annular area within the precleaner area, and wherein the annular area extends circumferentially around the sleeve; (d) a precleaner assembly (36; 124) provided circumferentially extending around the periphery of the sleeve (34; 122) and received in the annular area in the precleaner area (38; 125) so that environmental air flows through the precleaner assembly and into the precleaned air chamber, and from the precleaned air chamber into the air intake flow region; characterised in that, (e) said precleaner assembly (36; 124) comprises a panel (72; 146) of inertial separators (70; 140), said panel comprising an arrangement of inertial separators (70; 140) extending from a first wall (76; 142) to a second wall (78; 144) of the panel (72; 146); (f) said panel (72; 146) of inertial separators (70; 140) surrounds entirely said sleeve (34; 122) along said periphery thereof, and (g) said precleaner assembly comprises a scavenge chamber (80; 148) which is in communication with a scavenge outlet (42; 149) of the raincap precleaner (30; 120).