Willys Jeeps- no pillars /roof -why?

[tali1]

Willys Jeeps the classic originals - how come they have no pillars or roof? - i ask as it is said a roof adds a lot of structural integrity and i would have thought given the rough conditions it has to endure that a roof would be part of the bodyshell
Was army specification demand of a fold-down windshield the reason? -was this lack of roof a techincal oversight on the army's part? -or was it simply a cost measure?

[captainsmelly]

Separate chassis, so no rigidity benefit, also they were designed to be stackable for ease of transport and storage so the fold down screen made for a low height, and wheels able to rest flat on tops of the arches.
If memory serves.

[benjj]

As said above it is a combination of shipping/logistics along with the need for 360 degree arc of fire while moving or stationary.