The VE-7SF was a single-seat fighter ordered by the Navy.  It was equipped with two Vickers machine guns synchronized to fire through the rotating propeller.  The Vickers was later changed to a Browning design.  The VE-7SF was a VE-7F equipped with flotation gear.  The VE-7SF made the first takeoff from the Navy’s first aircraft carrier, the USS Langley, in 1922.

The photograph shows the number 10 aircraft of fighter squadron number 2 and the pilot.

More about the VE-7:

The Aircraft that Got a Company Off the Ground
VE-7 Production
Additional Models
VE-7 as a History Maker