There have been several previous threads on this going back to 2001. Most reflect the views above. My old boss on CFS (H) used to speak of his problems with the air test height climb requirement in the Whirlwind 10 - up to 14,000'. He said that the only way he could force himself to do it was to imagine the biggest set of swept wings attached out of sight. Perhaps that was a slightly special case since we were operating at around 60 kts or so and, at that sort of height, it looks as though you are stationary - quite disconcerting!