Hi Scott, here are a couple of pics of my TF 1/7 P-51 with an 18x12 Zinger and RCV 120. Full right rudder required for takeoff, and pulls it along pretty scale-line, IMO- only problem so far is cooling, so I'm slowly working on that

As I recall, according to the plans, I think the scale size would be 18", MAYBE 19", but I haven't actually checked my books.......