If helicopter uses air breathing engine how does engine work in simple level condition i.e lift eaual to wt.?

for an air breathing engine there will be an inlet and due to flight velocity air is rammed into the engine but for an helicopter it may stay at an altitude with out forward motion so how does air passes through inlet? does it have any sucking mechanism? Generally where will be the engine mounted on helicopter and what about inlet and exhaust? is it a cyclic operation with a limited air?