Helicopter Air Flow
Name: Paul S.
I was asked this question by a student with an
imagination regarding the force of the airflow produced by a helicoptor.
Is it possible for the air flow produced by that of a helicoptor to 'suck
up' (her words not mine) an adult human into the blades as it is taking
off or landing?
It would seem to me that the downward flow would prohibit this form
occurring; however, smaller objects such as small rocks and dust particles
may return to the turning blades with the turbulent air flow. Could an
object, the weight of an adult human, also be caught up in this turbulence?
I do not expect an object with the weight and density could be "sucked up"
by the helicopter blades while taking off or landing. When a helicopter is
near the ground, the air pushed through the blades "collides" with the
ground. The molecules have to go somewhere. The only directions are upward
and outward. Air pushed upward and not too far outward may find itself
above the blades, joining with the current pulled down through the blades.
Dust and sand can be picked up by a strong breeze, so they can also be
picked up by the air flow of the blades. A person might be knocked down by
this air flow, but not lifted up. Air flow with the strength of a strong
tornado would be necessary for that.
You are correct, when a helicopter takes off there is a strong down draft,
so strong it would send humans running for cover. Small sticks and stones
will pelt anyone nearby. Some of these could be swept up in the updraft that
occurs when the air swirls back up off the ground. But a person? I do not
Click here to return to the Physics Archives
Update: June 2012