photo #4039186

For the umpteenth time, please explain why there's a gap between the engine and start of the trail. Barium, etc., metal particles don't temporarily become invisible and then reappear. Could it be that it's simply water vapour, the by-product of combustion, taking a split second to condense and freeze into ice crystals? Kerosene (Hydrocarbon) + O2 -> CO2 + H20.Basic chemistry.