Hi,
just to complete any confusion left ...

Precession is what the vertical axis of e.g. a spinning top or gyro or the earth does when the axis tumbles. The bigger the angle the bigger the precession.

If you want to overcome the inertia of a fast rotating body you need more force than for the inertia of a still one (inertia along certain directions rises with rotation). Since the rotating engines of WW1 planes are not very long (=short axis), a plane like the pup or Camel is still able to do quick course changes.

However this has not much to do with the Camel's behaviour to go down in right, and up in left turns. The latter one derives from the added gyroscopic effect to the inertia, and the resulting torque, not precession.
The clockwise turning engine (in direction of flight) simply assists the plane when doing a right turn, in turning the whole plane to the right along its axis. If you want to turn to the left, the engine does not only not assist you, but you have to additionally overcome the engines torque, resulting in a rise, or a long rising turn, if not countered. Astonishing enough this was better modelled in RB "1" and in MS's flight sim #4 than in any other sims i know of.
There are certainly other things to regard, like propwash etc., and on the ground the axis' angle is greater than 0 in relation to movement ...
Greetings,
Catfish