Gidday to all, I'm at the final stages of building my first low wing off a plan. The model would'nt be well known to most, it's a Tumbalina 70. The plan shows no side or down thrust at the engine but the vertical stab appears to be a little offset on the center line. Could this be a mistake on the plan or is it done this way just as it is on fullsize aircraft? The rudder is central to the line but the front of the vertical stab is where the offset is. Looking from the back to front the offset is a touch to the left. Would this give me side thrust to the right? Will down thrust be required on a low wing? Any help would be appreciated. Kind regards, John.

It depends on how the airplane is designed, for example, a Cap 232 actually has up thrust. If the plans don't state up or down thrust, you may just have to test fly it and then add shims under the engine mount to give the proper results.

Interesting.
I was of the impression that right thrust was benefitial for low speed conditions, an offset vertical fin has more benefit at higher flight speeds.

Thanks fellas for the input. I'm a little worried that it may be an error on the plan so I want to be sure before attaching the fin. Perhaps the pros like Cafeenman and Minnflier could offer their expertise. Kind regards, John.

Just a bit of dribble here to get my post back up the top. I need more input and answers to my questions. Kind regards, John.

Well, to get particular answers, precisely WHAT the plane looks like would be nice to know.
Offset fins aren't unusual in full-scales.. P-51, T-28 etc.. but is the Tumbalina a scale/semi-scale/sport/aerobat/....?
Side and top views...

Righto Tall Paul, here are some pics of the Tumbalina. I don't think it's a semi scale, at least I've never seen a plane like it.

Here is another view.

and 1 more. I hope you can help. Kind regards, John.

Looks a lot like a Super Sportster, John.
No particular reason for any fin offset, modelwise.
If the vertical in the top view does show a distinct offset, it might be wise to do it that way.
I have a Big Bingo kit...85" span, low wing, looks similar, for large gas motors etc.. it shows no vertical offset.
I guess it's up to you.
The worst that could happen is you have to trim out the offset in flight.

Thanks Paul, I suppose that would work both ways, I could trim the offset in if it was needed. This offset would 'nt help with side torque at takeoff would it? Like Geistware stated, it would only be benificial at high speed. Damn, I don't know what to do, please make the decision for me. Heh heh.

When all else fails... follow the instructions.

Yeah righto FHHuber, the thing is there is no instructions, just 2 sheets of plans [&o] Kind regards, John.