I have a P1 fitted with 9450 DJI props with metal hub. I was going to check balance on the props. My mind must have been somewhere else as I was trying to remove the first prop, I was turning it the wrong way. It was tight so I used my motor wrench still turning the wrong way. It started to turn a bit with higher than normal force. Then it dawned on me I was turning it in the wrong dirlection. I turned it the other way and prop came right off. The hubs must not be splined or keyed as the prop is molded around the hub. The hub will still turn inside the prop if enough force is applied. It's still tight and I feel just fine for flight. Just thought I would mention this. Pay attention.