Yesterday I watched a friend fly his GP Pitts, what a great flyer. He has a OS 1.6 just as recommended. Two aileron servoes. The only mods he made was a pull pull on the rudder and a pushrod on the elevator. This thing flies great! He kept the weight down with the 160 and it goes straight up for a good distance. Landings are so slow you could catch it. The real Pitts is not a "out of sight" vertical airplane and to keep it scale neither should the models. For those who think it wont fly on a 1.6 your are incorrect, it flies just like it's full size counterpart and lande even easier.