Abstract: The Radar Cross Section (RCS) of bump inlet with alterable mouth parameters and a Pitot inlet have been investigated by experiment.The paper compares RCS of the bump inlet with RCS of the Pitot inlet and finds out the influence of mouth parameters on RCS of bump inlet.The results show that:①the bump inlet is a sort of inlets with low RCS; ②the ratio of the height of the bump to the thickness of inflow boundary layer should be appreciably less than 1.2; ③the angle between two top edges of the lip can be chosen between 120°and 135°; ④a 60°angle between the side edge of lip and horizon is optimal; ⑤the location of the bump relative to the lip would be best set between 0.7 and 0.8.The comparison results of the bump inlet with opening terminal and with rotating fan at the outlet indicate that the electromagnetic scattering comes mostly from the mouth of inlet .

Key words: inlet(intake), electrom agnetic scattering, bump inlet, Pitot inlet, radar cross section(RCS), mouth parameter