First helo experience was short-term S&R in K'sar detached from fixed-wing Valettas. Helos were Sycamores and did a 10,000 height climb which was nice and cold and no problem. When I later went full-time S&R on Whirlwinds, "low is good - high is is uncomfortable" ! Fairly common trait ... my Boss (long -time rotary) said that when he had to do Whirlwind height climbs (10k), he had to imagine a large pair of swept wings attached to the rear of the cabin to make it more acceptable.