Well, I always understood (various books quote it)OGE to start at about 1.5 times the rotor diameter above the ground, but the curve of hover power required vs height up till then is not linear.
Using this with the 212 and its 48 ft rotor, gives you a OGE height of 72 ft. The graphs quote 60 ft skid height and funny old thing, it's 12 ft from skid to mast top. So I guess that is a reasonable guideline.
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