One of the most effective "in tank" de- aerators is a roll of screen rolled up and inserted vertically in the oil tank. The air bubbles will adhere to the screen and go out through the tank breather and the deaerated oil will go to the bottom when the pressure pump inlet should be. Oil tanks should be tall and narrow.
Rex
My experience is similar to that of Rex. Have run a lot of Cosworth engines.
Cosworth's specs for oil tanks:
1/ Tall
2/ Round, vertically
3/ Tangential oil entry near top of tank
4/ Oil outflow from a cone section at bottom of tank
5/ Center screen/perforated tube de-aeration tube with LARGE breather to recovery tank
6/ Oil feed lines to be as short as possible, and large enough in diameter to provide "adequate cold flow".
This style of tank typically works well without mechanical de-aeration, UNLESS, the scavenge out from the engine contains large volumes of air. The shape of the tank combined with the "swirl effect" from tangential oil entry tends to naturally de-aerate the oil.
In my experience, gear style pumps pass more air than lobe and rotor style pumps, something it's useful to be aware of.
I also have experience with cars where the oil tank was fabricated to "fit" in a given space, was an irregular shape and perhaps a bit on the small side for oil volume. We
always had oil feed related engine failures with those cars/engines, until somebody (usually me) had a s***-fit to provide mechanical de-aeration. And then, the blow-ups stopped. Once I was told that after my s***-fit the engines were afraid of me, but I don't think that was the real problem.
Fordboy