Well last time i check flying Mig15 or in the Yak9U which are far different than a Scessna 172 , in yak using the small ww2 helmet to ovoided my head to wank all over the canopy because due to head movements..This is why there are pads little bit everywhere. Your head is not a wood stick it will act and move around, you cannot fly with all your muscles cramped for the whole flight.. This is why i asked this for years now same with turbulences frotements and air stiffness which are very different than a fishing boat on the water.. well actually a high speed boat would represent better a good way.. ;)