Hi. When a plane travels in a vertical circular loop, what is the provider of the centripetal force, required to produce the circular motion? At the top of the loop, there is gravity acting towards the center of the circle, so id assume that this is part of it, but what about at the bottom and sides of the circle? Gravity no longer acts towards the center of the circle, since it is always directed downwards. This is where my confusion arises. Thanks for the help, Dan.