T'aint natural et al. .I reckon that this is pretty widespread - certainly used to have the same problem ... above three HUNDRED ft, never mind 3 thousand. The Whirlwind air test height climb was, indeed, not much liked. My old Boss, who had mega hours on hiccopleeters, used to say that the only way he could complete a height climb was to imagine the biggest pair of swept wings in the world attached to the cabin behind him, out of view.. .My worst moment was when one of our brain dead Winch Ops put me over the side on the cable at 1500'. Now I know it was a 30 cwt cable, but it didn't seem that substantial at the time !! The ensuing 'discussion' included some pointers to his likely early demise and the legality of his parents nuptials