Calculating Engine Offset
Most model aircraft designs have a certain amount of down and/or
right thrust. The back of the propeller should be on the centerline of the
fuselage when viewed from above and on the
thrust line when viewed from the
If the model you are building has a thrust adjustment and you center
the engine mount on the intersection of these two lines then the propeller will
be in the wrong place.
Trigonometry page for more details.
This problem is very similar to
solving for dihedral.