Not strictly on topic - as I've never been in uniform, but a UH-1H ride with the RNZAF sometime in the late eighties comes to mind.
At a training camp as a civilian in the South Island with teams destined for Antarctica that summer.
Have a vivid memory of being strapped into one of the sideways facing fold-down seats with a full load of pax - rear door all the way back as we were hover-taxying, and thinking how extraordinarily quiet it was inside even with the doors open - compared to the Huey drum beat that you always heard from the ground.
Talking to the young pilot afterwards, and he told me that 50 foot rotor had so much inertia that he could auto-rotate, touch down, then pull collective and rotate the aircraft through 180 degrees to touch down again with engine still at idle.
Amazing.