I am finding that out, the 450 is suposed to 3D up to 25oz. Are the slow flyer props more for 3D than say the Electric labled props?

My 400xt is suposed to 3D models up to 15oz with a 10x3.8 or 10x4.7. The 450 is suposed to 3D up to 25oz with the same props. In order to do that wouldnt the motor need to have higher RPM given the same load to 3D a heavyer plane? Why dont electric motors have rpm ratings with various prop sizes and pitches? I guess I still dont understand watts as a power rating. I know more means more power, but I need to know how the power is delivered and how I can use it.

This is why I thaought I was going to be able to swing a bigger prop because the 450 has such a low Kv at 890, I thought it had more torque and thus could swing a bigger prop at a faster or same RPM and deliver more thrust. What am I missing?

Going from a YS .91 to a YS 1.20 makes perfectly good sense to me. I would never swing the same prop on both engines. 16X4 on the .91 and 17X6 on the 1.20 both at about 9,000 rpm.

I dont have a watt meter the LHS was out, so I am going to do rpm testing.