An O2U-1 observation seaplane off the catapults of the U.S.S. Raleigh, one of the then new scout-cruiser class. Note old vertical tail surfaces and no-dihedral sweptback wing.
Landplane version of O2U-3 with Townend ring;
Marine Observation Squadron 8M SU-2 scout/bomber: SU-2 was mainly similar to SU-1, with 170 m.p.h. top speed, 20,500-ft. service ceiling.
Special executive version of O3U-3 with Wasp engine had exhaust collector ring, spats, rounded tail.
O2U-4 had revised float without rear bracing. Changes on O2U-2 to -4 were mainly in equipment and performance. Amphibian versions spanned 36 ft. 0 in., were 29 ft. 8 in. long, and 13 ft. 7 1/2 in. high. Engines were 450-h.p. Wasp B.
The O2U-2 had wing dihedral and revised tail.
Amphibian O2U-3 doubled as fighter or bomber as well as observation, had heavy rear float bracing, later discarded.
Wasp C gave O3U-1 a 138-m.p.h. top speed and a 16,200-ft. service ceiling; fuselage side tankage was increased from 90 to 110 U.S. gal. Thirty-six were delivered to Navy in 1930, seventy-three in 1931. Landplane was 26 ft. 0 1/16 in. long, 11 ft. 6 in. high.
Hornet-powered SU-3 has low-pressure wheels; twenty were delivered in 1932 and served with Observation Squadron 9M.
Export V-50 series of 1931 had wheel spats and new powerful Hornet Series B (575 h.p. at 1,950 r.p.m.) in Townend ring, giving a 190-m.p.h. top speed.
V-70A was 1933 export model with enclosed cockpit, Hornet engine, top speed around 175 m.p.h., and spatted wheels.
The similar V-70B had low-pressure wheels.
Navy O3U-2 was cleaned up, higher-performance, carrier-based version with the Hornet, new landing gear, deeper fuselage with raised cockpits, and new wing cellule arrangement. Landplane length was 26 ft. 2 1/8 in. and height 10 ft. 7 3/4 in.; 122 were ordered in November 1931.
V-65F for Argentine Naval Air Service had a 600-h.p. Hornet R-1690-C and glazed cockpit hood, enlarged wing-root fairings, cleaner interplane struts, new rounded fin and rudder with small dorsal spine. Top speed of V-65 series was 180 m.p.h., service ceiling 20,000 ft., wing area 235.6 sq. ft.
V-66E was purchased by Great Britain in 1932;
SU-1 was first scout version, similar to O3U-2, had Hornet engine, balanced ailerons, 130-gal. tankage.
Service SU-4s had Townend ring and open cockpits, 600-h.p. Hornet, and 130-gal. fuel load. Twenty machines and one prototype were delivered.