ok then, let me put it this way. when you are having a first flight, you should be 3-4 mistakes high, with an instructor you trust. for me anyway, that was enough confidance. i was so thrilled and trusting in my plane, and instructor, i wanted to go up again as soon as i refueled. i was faster to ask than my instructor was to say either yes, or no. if you have a good trainer, unless you do something stupid like pourposely stall, or something along the lines of that, the trainer will correct for not only itself but you as well. i would recomend the pt-40. but also, your instructo should be you copilot, not a little electronic device. if everything is properly done, it is completely uneccessary. as about the .50 size engine, i have clocked it at less than a minuet less time on full throttle than my .46. the extra power comes because the engine is ringed. that means that only a small area is rubbing, or making contact with the sleeve. .04 cubic inches alone will not give you 10% more power. i recomend it because, when you get into trouble, especially when you are learning, a good but not excessive amount of power is a great thing. probably the best example of that was at a fun fly. i was doing a 10 foot inverted pass over the runway with my easy s[port, with the 50 sx ringed. i had a brain fart and rolled it off in the wrong direction. i ended up over the pitts, and the only reason i was able to get out of it, was becasue of that engine. it was able to hang vertical after an accidental lomshevak over the pitts. i never would have made it out with 10% less power, and once again, the fuel consumption is infintecimally more than the .46. also, it will last longer, because of the less wear between the sleeve/piston fit. i would recomend that engine and guard that opinion with my live. the pitts were crowded, and i could have easily killed somebody, but that engine saved not only my expulsion from the club, but also possibly lives. that could have even had the club shut down.