Cat v Pigeons
No gyroscopic precession? Well I've been lucky enough to fly several types of helicopters as well as some big piston-propellor fixed-wing aircraft. I can confirm that, certainly on the fixed-wing propellor types, they all suffered the effects of gyroscopic precession from the propellor.
The big difference between a stall turn left and one to the right was caused directly by a combination of the propellor slipstream effect and the gyroscopic precession. During the take-off run on the tail-wheel types you definitely get a pronounced yaw as you lift the tail, again caused by the nose-down torque applied to the rotating propellor being translated into a yaw.
Are we saying these gyroscopic forces don't apply to helicopters?
The difference is that helicopter rotor blades have flapping hinges, which alleviate the feedback into the rotational axis (the crankshaft of your aeroplane engine, or the main rotor shaft of a rotary winged aircraft) by allowing flapping to equality. Cierva discovered the need for these flapping hinges during flight trials, after he scaled up his small model aircraft. The latter had highly flexible blades; his full sized aircraft didn't, what's more he added bracing wires to prevent flapping. The result was his aircraft kept rolling over on takeoff until he realised what was happening.
Basic rotor theory!