Originally Posted by RWD_cossie_wil
I would imagine it works on same principle as an aircraft engine inlet duct , which on fighters etc (and on some f1 cars- barge boards etc) is positioned slightly away from the main body, as it removes the turbulent boundry layer of air by effectivly "peeling" it away from the smooth airflow. turbulent air is inherent in any intake system,by keeping the airflow laminar into the compressor as much as possible it is far easier to conrol surge/stall etc
Isn't the whole point of fighter air inlet systems to control the inlet air speed and density. This is for keeping the air intake velocity sub sonic in all situations no matter how many machs the aircraft may be doing. This is the whole point of the most popular moving cone (MIG 21, Mirage,...) and deflector plate designs (F14, Mig 25, Mig 29,...).