ORIGINAL: mjunior
PS: also if FOD screen doesn't bring any impact to engine performance why the full scale jets don't have them.....?
The basic answer to that question is that modern full-scale turbines have multistage axial-flow turbines that are *much* more sensitive to disruptions in airflow than our simple (and inefficient) single-stage centrifugal-flow compressors.
A FOD screen on a full-scale turbine that was fine enough to catch the kind of small FOD that the engine can suck off the ground (that would be huge FOD for our engines) would totally disrupt the airflow needed by their high efficiency compressors...
Bob