It was merely two helicopters brought in to dry off the field with the whir of their rotary blades.
The fast chopping noise of a helicopter's rotary blades gradually grew louder.
Heads popped off around the circle of the dozen bushmen as though someone had removed them with a great rotary blade.
To make the sections, the scientists moved the platform horizontally through a rotary blade, which was also horizontal.
A pizza cutter is a rotary blade, sometimes rotating using its own motor.
The sound they made coming through the woods was like the whirring of a large rotary blade cutting through a field.
The rotary blades are not sharpened in the same way as a conventional mower blade.
The minisub jammed the rotary blades during its intake phase.
Another catheter had rotary blades at the end, which cut out the plaque instead of compressing it.
He held the small power saw with a rotary blade.