Is an open radiator more vulnerable to damage than a closed one?

[WTE_Galway]

They also have a significant effect on performance of some aircraft.

A case in point is the Lagg 3 that flies like a pregnant sow at lower speeds if the radiator cowl is open.

[EJGr.Ost_Caspar]

Yes, they increase drag.

[Treetop64]

Originally Posted by WTE_Galway

They also have a significant effect on performance of some aircraft.

A case in point is the Lagg 3 that flies like a pregnant sow at lower speeds if the radiator cowl is open.

The LaGG-3 flies like a pregnant sow, period. Just less so if the radiator cowl is closed.