Econo...
I ran one of my Patriots with a piped TT.46 on 40% nitro... Wasn't good for it, but by golly that thing would sing! We were using the 40% Powermaster in some 1/2A racers then, so I just tanked up the ol' Pat with it, and let it howl! APC 10x9 prop, don't remember the RPM's, but was clocked around 120 back in '97...
I've used the OS .46 SF, the Thunder Tiger .46 Pro, and the Jett .50 (bought used from a guy on the 'Net) and they have all worked well on this plane. .50 was the fastest, but I preferred the OS's lower weight. TT worked just as well.
I've seen a Pat with a YS61 Rear Exhaust, and it landed at like a 30 degree angle of approach. Too heavy for me. I require my planes to slow down somewhat on landings (that means I like to drag them in very slowly), so I try and keep the weight down, sometimes at the cost of performance, but the overall flyability makes up for it...
Phil in Austin