What type of engine?
2 or 4 cycle? I am willing to bet its a 2 cycle.
Nothing wrong with a 2 cycle for 3D on these types of planes however, a four cycle produces much more prop blast over the tail because they can swing a larger prop.
You may be right in thinking that not enough air is getting to the rudder at High Alpha. (3D)

I'm not that familiar with what a limbo dancer looks like. Do you have a pic?