Too bad the bottle wasn't properly visible throughout the looping :(,(reply>), @HotelPapa100 You're absolutely right, but I would argue that if negative Gs are being applied to the airplane, then it's no longer a loop. That's the point of view from where I wrote my comment. I did make one small note about inverted flying. But during the loop in <b>this</b> particular video, I'm confidant, the water stayed at the bottom of the bottle. I think you probably agree. ,(reply>), +gizmoguyar Actually, no. A loop is usually flown keeping g forces positive for the airplane/passenger. But it is perfectly feasible to loop over the top with less than 1 g centripetal acceleration, meaning that gravity does the job of bringing the plane round and having something to spare to accelerate the payload towards the roof.<br>It would mean the pilot would have to apply a little bit of forward stick up top, but if you want to fly the loop as round as possible you have to release a bit of pull at the top anyway, and in a slow loop that can mean you go into negative g's.,(reply>), @Schizophrenic Enthusiast It's a physical impossibility to apply a centripetal acceleration to the airplane and have the acceleration not apply to the water as well. In other words, if the water were to be forced (downwards) to the neck of the bottle, then the airplane MUST be accelerating upwards relative to the ground. But we know that the centripetal force MUST point towards the center of the airplane's loop. Therefore it's not possible for the water to be forced to the neck during a loop. It's certainly possible for the water to fall to the neck during inverted flying (only gravitational acceleration applies), but not a loop. As chaytacsnipes said imagine swinging a cup of water over your head. It's impossible to have the water fall out while the cup remains swinging. Even if both the cup and the water are allowed to fall due to gravity, they will fall together and the water will stay in place.,(reply>), Hell no ! the water would not stand still at the bottom of the bottle, the loop needs to be done quicker in orsder to create enough G force to keep the water at the bottom. If you could see the bottle, the water would rush up to its neck when Tom was upside down relative to the ground.,(reply>), @Kram1032 get a cup and some water and swing in around with your arm and you see the same thing. Not so fascinating looking at still water if you ask me.