Unusual or rare applications of armour In World War One improvised armour was used in trench warfare including reinforced helmets and in the case of some German units breastplates In the Great Patriotic War a number of units of Soviet shock troopers were equipped with steel breastplates The aircraft armour section could be expanded with a discussion between the three facets Durability redundancy and armour Some examples such as the Ilyushin Il 2 and the Junkers J 1 might also be appropriate