Wilbus, torque is just a twisting force. A force must be applied to the propeller to cause it to rotate clockwise. A force of = magnitude, but opposite direction, is produced which tends to roll the airplanes fuselage counterclockwise. And this does cause the airplane to try to turn left on the runway some, although the most noticable situation that you would see torque is in a low speed situation where you suddenly apply full power.
There are 3 other forces that act on an airplane making it turn left on runway as well (assuming it has a clockwise rotating prop, otherwise obviously these would make it go right). The first is slipstream swirl. This is what you mentioned. This is the corkscrewing motion imparted to the air by the propeller. This air swirls around the fuselage until it reaches the vertical stab. When a prop plane is at a hi power setting and low airspeed (as in takeoff) the increased aoa creates a horizontal lifting force that pulls the tail to the right and causes the nose to yaw left.
P-factor is another problem. P-factor is the yawing moment caused by one prop blade creating more thrust than the other. The angle at which each blade strikes the relative wind will be different, causing a different amount of thrust to be produced by each blade. If the relative wind is above the thrust line, the upgoing prop blade on the left side creates more thrust since it has a larger aoa with the relative wind. This will yaw the nose to the right. To really see p-factor, you must be at a hi power setting, and the thrust axis must be displaced from the relative wind.
The last problem is gyroscopic precession. This is based on the properties of a spinning object. When a force is applied to the rim of a spinning object (in this case, the prop), parallel to the axis of rotation, a resultant force is created in the direction of the applied force, but occurs at right angles ahead of the rotation. Pitching the nose of the aircraft up produces an applied force acting forward on the bottom of the prop disk, or backward on the top of the disc. The resultant force would cause the nose to yaw right in the case of pitching up, and left in the case of pitching down. This means that as the tail comes up on a taildragger, the airplane may yaw left.
