Improvements in or relating to air intakes for power units for fast moving vehicles embodying one or more turbines

647,632. Cleaning gases. NAPIER & SON, Ltd., D. Nov. 23, 1948, No. 30404. [Class 8(ii)] [Also in Groups XXVI and XXXIII] An air intake for an aircraft or other fast-moving vehicle embodying one or more gas turbines comprises at least one forwardly facing inlet duct. making an abrupt change of direction at an intermediate point in its length, and a rearwardly extending branch passage leading from the duct at the said point and in such a direction that particles of matter carried in the air stream tend, by their momentum, to enter it. In the construction shown in Figs. 1 and 4, air enters by way of an annular duct B' formed in the spinner B of the propeller and passes through a stationary annular duct comprising an outwardly directed part C1 and an inwardly directed part C2. Droplets of water, ice and dust in the air tend to be carried by their momentum through a branch passage D. A series of bell crank levers E, E1, each pivoted at E2 and connected to an annular shutter D2 by a link E3 and to each other by a cable F, are operated in unison by an electromagnetic actuator G connected to one of the levers so as to move the shutter D2 to control the opening of the exit of the passage D. In a construction comprising two turbines mounted side by side and driving a single propeller or contra-rotating propellers M, M' as shown in Fig. 7, each turbine has its own intake duct O, O1, the branch passage O2 being controlled by a flap P operated by a servomotor P'.