P-factor IS an issue with trikes. Although you don't have P-factor while rolling down the runway, once you rotate and begin climbing, you do. So the difficulty is mananging the transition from no effect during the take-off roll to the angle-of-attack proportional effect during rotation and climb out.

Of course, this effect is more prevalent in full scale planes, and much less noticable in models, especially when compared to the relatively large amount of torque we can apply to our planes during take-off.

- George