ORIGINAL: Thomas B

And yet a goodly number of full scale aircraft do indeed have some right thrust built in, to minimize torque/P-factor/spiral propwash effects.

Yes, you do use trim and airmanship to get the final results you need, but aircraft often have some sort of compensation built in to help reduce pilot workload.

Look at a Cessna Caravan sometime..it has a remarkable amount of right thrust and down thrust built in. A considerable number of single engine aircraft have some right thrust built in. and, there are other compensation fixess as well.

Lots of full size aircraft do thrust line for pitch effects as well. A J-3 has no down thrust, but its big brother, the Pa-11 Super Cub has 4 degrees of downthrust built in.

Look at a side view of a Lake Amphibian sometime....massive upline thrust to counteract the high thrust line.

The modern line of RV experimental aircraft have right thrust built into the motor mount.

Older aircraft, such as the Aeronca Champ, often have the vertical fin offset to help with torque/-factor/spiral propwash. In fact, an article on the Waco club (full scale) website reccomends 1 to 4 degrees of fin offset to help with torque/P-factor/spriral prop wash effects:

http://www.americanwacoclub.com/news...g_v1n3v1n4.htm

Lower powered full scale aircraft typically have the least compensation of these effects, while higher powered aircraft have a bit more.

Finally, some aircraft are rigged with one wing having a tiny incidence difference to the other wing to help with torque/P-factor/spiral prop wash.

Personally, I find it completely acceptable to do some thrust line adjustments on scale models to help minimize trim changes and needed pilot inputs.