Instead, calibers measure the length between CP and CG, divided by the outer diameter of the rocket, allowing for a much more fair comparison between different rocket sizes. For context, a CP of 1.5-2 is considered good, while numbers outside of that range tend to be either under-or-over-stable. | Instead, calibers measure the length between CP and CG, divided by the outer diameter of the rocket, allowing for a much more fair comparison between different rocket sizes. For context, a CP of 1.5-2 is considered good, while numbers outside of that range tend to be either under-or-over-stable. |