Remarks by Dan Shumaker from Peter M. Bowers book, Curtiss Aircraft 1907-1947:

"The R-6 (Model 2A) of early 1917 was a long-wing seaplane like the R-3 and differed from it mainly in use of the 200 hp V-2-3 engine and 3 of dihedral in the outer wing panels.

All but one of the seventy-six R-6s delivered to the USN had twin floats, serial A-193 being fitted with a single float.

USASC R-6s were delivered both as landplanes and as twin-float seaplanes. The Army ordered eighteen, but most are believed to have been released to the Navy before Army acceptance.

Navy R-6s became the first American-built aeroplanes to serve US forces overseas in WW I when a squadron was assigned to patrol duty in the Azores, Portugal, in January 1918.

Average cost of the R-6 and similar R-9 was $15,200 less GFE. USN BuNo. A-162 to A-197 (36), A-302 to A-341 (40). US Army serials: 504 to 521."