Let me correct myself. I am certain the last airplane is a Curtiss F8C not an FB-5 as the shape of the tail and sweep of the wings clearly rule out the Boeing FB-5 as well as the tail wheel instead of skid.
Mark Lincoln
26-Apr-2015 22:01
The fourth airplane must be a F8C or a O2C-1 as the F5B was a parasol monoplane. That would date the photo as being no older than 1930. F8C-4s were first built in 1930, The similar O2C-1s were built in 1931. The N2C in US service was only operated by the Navy Reserve. By the late 1930s they were converted to tricycle landing gear and equipped as radio controlled target drones
Steve McDonald
26-Oct-2008 17:50
I'll go out on a limb and state that the first three planes are the Curtis N2C2 circa 1937. The fourth plane in the distance is a bit hard to distinguish between two models. But I think it is either a Boeing FB5 circa 1927 or a Curtis F8C-4 circa 1930