How can I calculate the diameter and strength of a helicopter's downdraft?
September 23, 2012 3:36 AM Subscribe
How low can a helicopter fly before people on the ground are affected by its downdraft? Is there a standard way of calculating downdraft strength and diameter at various heights?
posted by embrangled to travel & transportation (7 answers total)
I am involved in an event which might be filmed by TV news choppers. For safety reasons, it is important that any downdraft felt by the participants below be no stronger than a light breeze. Ideally, they should feel no downdraft at all. I would like to give clear instructions to media organisations requesting that they keep their helicopters a safe distance away from the event. How can I calculate what that distance should be?
(I don't know the precise helicopter models involved, but let's assume we're dealing with small to medium commercial craft).