Further to my earlier post:- I cannot recall where I read about it but the F-4 incident I was thinking of was not actually in pouring rain but it was on night ops. Apparently they were doing night training and to save space on the apron as they came in to refuel they were folding their wings. Duly refuelled th aircraft concerned taxied out and took off. According to what I remember the pilot was not aware of anything amiss until the crosswind turn after take off when he reported a severely degraded roll rate.