</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">. .When aircraft are being tested at 0.98 many parts of the airframe and the engine intake airflow are already supersonic.. .</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">what part of the intake flow is supersonic? if anything a normal shock forms across the inlet face and pressure losses are incurred but flow will be subsonic thereafter(M~0.6 by design). the initial section of the inlet is a diffusing section designed to change the velocity into static pressure and reduce the speed of the air to M~0.4 which is usually what the first stage rotor can handle.. .. .if the flow was supersonic in the inlet, it would accelerate even more in the divergent section