I've noticed the design change on the bell housing on the P3 motors. It's very neat. But it's also difficult to gauge just how tight the props need nipping up. The P2 props had what felt like metal centres. It was very hard to over tighten. These new props, however, seem to have a lot of give past maximum torque. Having used them myself I could easily foresee a situation where someone overtightens and stretches the plastic, thinking that the prop is secure... but distorting the centre thread so vibration could work it loose. It feels like a bit of a design oversight. How far do you nip?