Intake momentum drag

[Superfly]

Hello everybody,

while going through my performance notes, I came across something that is not very clear > A JET A/C ON TAKE-OFF RUN SUFFERS FROM SLIGHT REDUCTION IN THRUST DUE TO INTAKE MOMENTUM DRAG

I can't figure out how it can be, is it the drag caused by the intakes of the engines that cause turbulent airflow and therefore a less efficient compression/combustion/detent ?????

Any help will be well appreciated ! - SF