A related question
Yesterday morning, it was beautiful flying weather, but bl00dy cold!
I left my house, de-iced my car, and drove to the airfield. The ground was frozen solid as I had my aircraft pulled out of the hangar. I pre-flighted, there was no ice (not surprising since the aircraft had been hangared), so I climbed in and turned the key. The aircraft wouldn't start in the cold weather.
An hour later, I returned with another group member, who was armed with a heater. We pre-heated the engine, after which it started fine, so I was able to fly. Woohoo!
Except that, in the hour-and-a-half or so while I was trying to get the engine started, a decent (1/2mm or so) layer of rime ice had formed on all of the flying surface.
Question 1: Where did this ice come from? The aircraft had come from a warm hangar - it would have been warmer than the dry ambient air, and so should not have caused any condensation to occur. As the aircraft cooled down in the outside air, it would never have cooled below the ambient air temperature. In fact, ice formed even on those surfaces where the morning sun was shining. Neither I, nor anyone else who was there, could explain the reason for the ice forming.
Qeustion 2: What would have happened if the engine had started first time? I'd have gone flying with no ice on my wings, and remained clear of visible moisture... would ice still have formed? Would it have affected the flying characteristics of the aircraft significantly? The ice, by the way, was invisible (white rime-ice on a white aircraft) unless you run your hands over it, so I would not have noticed it forming, and would not have been able to return for a precautionary landing, nor make any compensation for increased stalling speed, etc.
I have to admit to being slightly worried by this, as well as confused.
FFF
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