I set my profiles up for zero offset on the engine and zero rudder offset.  But, if I'm not sure of the offsets I try to err on the side that yaws the plane to the outside.

I like a wee bit of right thrust, because it helps get the lines tight again quicker. Might just allow me to save the plane when the lines get slack, for whatever reason. They all get slack sometimes, most likely due to wind or turbulence, but never due to PE.  Steve

I sink the aluminum shims to ply doubler surface level, but even then, you should make sure thrust line passes back inward (spanwise) at least to the c.g. position. Martin Hepperle used to have a nice derivation of spanwise lift center position (not MAC) for controlline models with rectangular wings, which would be a bit outboard of its position for tapered wings, and it depends as Phil says on span and line length. I copied his derivation and results, but am not where I can access them. I know I've posted them here or there, and the oft-shunned search will probably find them. They are based on finding the spanwise point where inboard and outboard lifting moments total zero (balance). The technique can be extended to other shaped wings, but phil's figures are pretty close for planes you fly. The spanwise drag center should coincide with the lift center computed for rectangular wings.

Essentially, all this means is that one should just be careful that the thrust line doesn't yaw the plane inward on the circle. You get some help from drag, but some offset is probably desirable, especially when wings aren't placed symmetrically spanwise - or as Leonard on SSWF would point out fuselages aren't placed at center span. Anyway, I can't see a couple degrees out thrust hurting anything, although the thought that the outward thrust component from modest offset is signicant is erroneous. It's yawing torques that concern us most, to prevent greater tension losses than an couple degrees worth of thrust. Out thrust ensures the correct yaw angle for the speed you choose. If you can get things perfectly tangential without out thrust or rudder offset (which I don't advocate)(Edit: I meant that I don't advocate much, if any, rudderoffset), then you're speed independent. 'not sure that anyone can do that. Since this is not the "south forty," called the engineering forum, I will not explain why, my last proof of this statement having elicited a lot of abuse from those who "don't need no steenking math." That post probably still lurks around here somewhere anyway.

SK

Thanks for all the replys, I did make some zero deg engine pads and tried them, but I was fighting engine runs and tank problems.Got the tank worked out and engine run pretty good but Im flying on too long of lines. They are labled 61ft but the guys I fly with have bigger planes and they say theirs is 61ft and mine are at least a foot longer. I will cut my lines down and try all this again. I didnt notice a "positive" result in zero deg thrust when I tried it though. Again, trying props and getting my lines correct,I will try it again unless its good. No,I really dont like experimenting unless the stuff just isnt working,but if one wants the best performance from their ship then yes its part of the game.