Gyroscopic precession

something to do with gyroscopic precession.

No, klippy, that is something entirely different!
Gyro precession is a reaction to an action. Your gyroscope, whether it be a prop, a flywheel or whatever, will travel quite happily along the line of it's rotation BUT
when you try to twist it while it is spinning, it will 'fight' you and try to add it's own turn at 90 degrees to your forced movement.
It is hard to explain, but easy to demonstrate. Put a silly big, low pitch prop onto an eleccy motor, spin it up, with the motor held in your hand.
The combi will happily push and pull along the line of the shaft, or sideways/up and down in the line of the prop
But apply 'up ele', and feel what happens to the motor - it will try to twist left or right as you tilt it up. The heavier the flywheel, the more pronounced this twisting action.

'Tail-dragging' in flight is a visual indication of lack of speed, or incorrect wing seat angles.
Lack of speed, = holding in up ele to generate enough lift to fly, = almost stalling!

Wing seat angle = the wing leading edge is too low relative to the te and fuz line, so the tail has to hang down to get a positive angle of attack.
You can see the other extreme too, where the tail is stuck up like the back of a chinook.
A small angle gives a visual suggestion of more speed, and in practical terms, a bit less fuselage drag, but too much looks silly.

Ah ha, so with a silly big prop (I've tried a 15x4) when you loop, the aircraft will try to screw out to the left or right depending on the prop rotation. By extention when you turn right the aircraft might try to pull up or down, and when you turn left the aircraft might try to down up or up.

That's it! Don't forget, very high rpm's on a small prop have a gyro effect, too. It's all about the rotating mass refusing to change directions easily.
Read up on the flight characteristics of full-size aircraft with a ROTARY (not radial!) engine!

I was going to mention that.
In a number of WW1 rotary engine fighter types, with there dodgy stall characteristics, sharp turns were only recommended one way where the nose was forced down, the other way, gyro precession nose up, stall, spin, crash!
Of course really good pilots could use this to their advantage and achieve a very tight stall turn.

It also makes a straight stall much more serious. Stall, sudden nose drop, and you don't have to wait for a spin to start, the gyro precession positively makes it happen!

Its not just old age that requires the Shuttleworth pilots to treat their rotary engine types rather carefully.

Soooo, under the right conditions, when you turn, the aircraft may appear to drag it's tail!

I understand that the Lomcevac (sic) aerobatic manoevre is based on this very phenomenon, the plane actually rotates around the prop, which is acting as a gyro.

Yes, but fortunately on most electric planes the prop is only a tiny percentage of the all up weight and even outrunners have a small diameter so gyroscopic forces are small but it is interesting to note just how heavy a rotary was when compared to the airframe.

The Oberursel (close copy of Le Rhone) weighed about 330lbs.
The Fokker Triplane weighed just 895lb empty (engine 36%), 1292lb loaded (engine 25%).

In electric model terms that's more or less the equivalent of not only the motor but also the batteries all mounted ahead of the firewall and going round at the same speed as the prop!

It also explains why its a struggle to get the CofG far enough forward on many rotary engined types.