XBY-1 and aspeed,

Gyroscopic precession is a strange thing. The details of how and why are beyond my total understanding, but the 'what' is easy to describe.

When I was much younger, simple gyroscope toys were available. A shaft with a flywheel weight was mounted in a frame of two circles at right angles to each other (to clear the rotating flywheel.) It was a "child's top" reduced to schematic. Such tops remain upright so long as RPM is high enough, remember?

If you've ever held the axle of a bicycle wheel and spun up some RPM, then tried to tilt the axle, you've SEEN that the axle resists any tilt you try to create. The wheel pushes strongly to tilt in the direction 90° later in the direction the wheel is rotating!

There are equations that calculate how much torque this creates, and which sense (direction) it acts in, using mass and speed of rotation as terms. On a 'standard' rotation engine in a CL model, e.g., a 'pitch UP' control input equals pushing the top of the prop disk back. Precessive load acts as if the model was pushed back 90° later, i.e., outboard tip pushed back relative to the model's forward motion direction.

This is completely reversible, and also applies to the "axis turning effect" of flying in a circle. When upright and level, DOWN control input causes a nose-in gyro load. (It is a 'couple', strictly.) BUT DOWN inputs sharp enough to matter usually occur when we fly "corners." When we're inverted. the basic direction of flight is reversed, thus so also is the resulting gyro 'couple.'

For stunters, this helps when we do sharp corners in pitch. LH engine rotation, as you've found, helps other high torque situations - racer take-offs and goosed throttle in low-speed Carrier mode. A stunter's maneuvering drag tries to slow the model, which increases the thrust load on the prop - which means the lower 'cruising' torque has to increase for an instant. (The model does NOT slow instantly - it enters a corner with the momentum it had when you popped in the input.)

Standard stunters today almost all use the reversed bellcrank setup. Sharp UP input from upright level flight creates a gyro couple trying to yaw the model nose-out. UP line forward moves the effective aim of line-pull further forward of the CG, That tends to oppose the gyro nose-out couple. So, our bellcrank's pushrod goes to the left (usually) of the bellcrank pivot, passing over the leadouts. Reversed engine rotation would reverse the odd effects, and the BC pushrod would go outboard of the BC pivot Simpler and less crowding over the bellcrank.

AND "UP line forward" wouldn't be necessary.

OBTW, re: old peoples' memory? The other basic comment is that:

"Memory is the second thing to go."

....."So, what's the first thing to go?"

"Er...uh..."