For some reason a techie brought a min-max thermometer along on one of our border detachments in Oman in the early 80s. Popped it under my (green) flying helmet on the seat of my Huey after landing and left it there for an hour late one morning. Around midday I went back to check - it had reached 88 deg Celsius.
Once I'd seen some Oz troops using Camelbaks in the late 90s I bought one and kept it strapped to the back of my 212 seat in Borneo. Our doc said that if you feel thirsty you are already 5% dehydrated. Just make sure you train your bladder to last as long as the a/c fuel tank does - see Oldbeefers comments earlier
