ORIGINAL: RCKen
I broke in an OS 55 AX this last weekend (for the GP Cherokee review that I'm doing) and had no problems at all. I used the prop that I planned to fly with (according to OS's instructions), which was a 12x7. I also had a Pitts muffler on the engine as well. I didn't have any issues at all with the break-in. The instructions call for alternating between rich (4-stroke) and lean (2-stroke) operation through the first tank. I actually ran 2 tanks through the engine doing this. The best way to sum it up was that it runs like an OS.
Ken
I agree, I have two of these engines and all I could say was "what break in?". Both ran excellent from day one. One of them never even ran through a tank on the ground. I just set the high speed needle and took off. All either have ever needed was to lean the low end slightly after a couple flights.
What do you think about the Cherokee? Did you read any of the posts I made regarding the tail coming off of my first one? My new one is epoxied in place. The first used a .46-AX but I made my second one electric with the recommended Electrifly motor and ESC. It's my first electric plane other than my foamie T-28 and I was skeptical but I'm actually kind of impressed after flying it a few times. The recommended setup flys it just as well as the .46. I miss the noise and smell though. I may end up with the OS .56FS in it one of these days.
Mine also seems to need a ton of elevator when landing with full flaps. In fact, you could run out of elevator if you don't get the approach just right even with the throw as much as it will go. It seems to land a little hot too, even with the flaps so I suspect it might be a little nose-heavy. I made a bracket last night and put my receiver battery behind the servos. This shifted the CG back approximately 1/4 inch. I'm going to fly it Saturday morning and see if that helps.