MI_RadialMotionBlur rendering problem with propeller

Hi, I am using the MI_RadialMotionBlur to render propellers in real time by following this document (Radial Motion Blur | Unreal Engine Documentation)

The rendering result seems not very good.

This picture is my static mesh. The length of blades is about 5 cm.

This is the rendering result with default parameters (angle=0.01, RimRadius=42) , looks not bad but I need the blur shadow of propeller cover the whole circle.

However, by increasing the angle, the original mesh becomes dark and the blur mesh becomes vague.

And in my case, if the angle is larger than 0.07, the rendering results seem all the same, no matter it is 1 or 100.

I am also not very sure the meaning of RimRadius, the following two picture are RimRadius = 0.01 and 100 respectively, for me they look not very different.


It seems that the default MI_RadialMotionBlur works very well with something more like a circle, but not very well with three or two bladed propeller. The material is implemented with blueprint so it is actually opensource, but to be frank I am not expert in materials and shaders, and haven’t any ideas about how to improve it.

Does anyone have some suggestions and improvements, or facing similar problems?