Offset arrangement of biplane wings

Answer 1

There are three distinct formats of wing stagger:

Zero-stagger or straight up and down arrangement of the two wings of the Biplane, as in the Wright Bros and some early Curtiss models. Both wings are more or less the same distance from the nose of the aircraft.

The most common stagger arrangement is when the upper wing is placed forward of the lower wing. This is referred to as 'positive stagger' and can be found on the majority of biplanes past and present.

Occasionally negative (or 'Reverse') stagger is utilised where the upper wing is position aft of the lower wing.

Aerodynamically there is little difference between the alternative layouts. The reason for using stagger is to provide the pilot with good access in and out of the cockpit and to optimise his field of vision while still maintaining the proper centre of gravity for the airplane.