Well I understand what your saying but I owned...well my father owned this engine before and loved it. I have other friends who fly pattern with an Excelleron 90 with a OS 120 Surpass III and they agree that the engine is too weak to fly pattern on this plane. Yes it will take the plane vertically high enough to accomplish patterns, but because it isn't sufficient in power, there is a lot of rudder and elevator work involved. Yes I have used a YS and still do not like it. I'll post again when I run this engine and post about its efficiency and how well the plane flies.