Usually aerobatic engines use a 'dry' sump lubrication system rather than a conventional 'wet' sump design to prevent oil starvation.
They also use fuel injection rather than a carby as the float closes the needle and shuts off the fuel when flying inverted.
That is the risky thing when doing loops with the Tiger Moths, as when you reached the top of the loop the fuel shuts off and sometimes the needle would stick shut. You then had to dive towards the ground to use the extra air speed to turn the engine over to try and re-start it, as they didn't have a starter motor. An interesting experience no doubt!
