Are we talking about the WM CAP 232 46R? If so then the 70 FL should do more than pull it vertical for 3 secs. The plane is just a shade over 5.5 lbs and even a humble 46 2C turning an 11x6 will pull her vertically, albeit not unlimited. A 12x7 is not really too much prop for that engine esp when the plane is only 5 lbs. What is your engine taching? The FL is less powerful but not to the point it only pulls a 5.5 lbs plane vertical for only 3 secs.