[GerritJ9]

Not necessarily- it depends on the internal design of the fuel/oil tanks. One would asume that the oil/fuel tank designers were aware of the contents of the tanks being flung around during violent manoeuvres in combat, and added baffle plates to prevent or at least minimize te risk of fuel/oil starvation. The latter would spell DEATH to nearly all engines. Plain bearings desperately need a constant and copious supply of oil to survive- interrupt that supply, even for a few seconds, and your bearings are seriously damaged if a load is applied to them. Ball and roller bearings are much less sensitive in this respect though they, too, need oil to lubricate and cool them.