Vought UO-1 / UO-1A / UO-2 / UO-4 / UO-5 / QO-1


1st Flight 1922


Crew: one

Length: 28 ft 4.5 in (8.65 m)

Wingspan: 34 ft 4 in (10.47 m)

Height: 10 ft 2 in (3.10 m)

Wing area: 270 sq ft (25.1 m2)

Airfoil: Navy N-9

Empty weight: 2,074 lb (943 kg)

Gross weight: 2,774 lb (1,260 kg)

Powerplant: × Wright J-5 Whirlwind 9 cylinder air cooled radial engine, 220 hp (164 kW)


Maximum speed: 106 kn (122 mph, 196 km/h) at sea level

Range: 357 nmi (410 mi, 660 km)

Service ceiling: 26,500 ft (8,080 m)

Wing loading: 10.3 lb/sq ft (50.2 kg/m2)

Power/mass: 0.079 hp/lb (0.13 kW/kg)

Climb to 5,000 ft (1,520 m): 5 minutes


Guns: 2 x .30 in machine guns


Initially designed as a seaplane, the UO-1 was soon classified as “convertible,” using interchangeable single-main float or wheeled-landing gear (these UO-1’s were designated UO-1C). 

First flown in the fall of 1922, the UO-1’s entered service with the U.S.S. Richmond in 1923. 

As their superiority over potential competing types became evident, they became the only observation type in use on the fleet’s catapult-equipped combat ships. 

The 15 first-class battleships were each equipped with one or more UO-1’s. 

Two or more UO-1’s were used aboard each of the new scout cruisers comprising the Navy’s scouting fleet.

In 1922, the first UO, with the Aeromarine U-873 engine, was modified for air racing. 

It had a brief undistinguished career. 

Subsequently reconfigured as a two seater and  equipped with a Wright Hisso E-3 engine, it was re-designated as the sole UO-2 and used for general utility purposes. 

With the advent of carriers, other UO-1’s were equipped for carrier operations.

The Vought UO-1 was the first airplane to be catapulted from a battleship at night. 

On November 26, 1924, Lt. Dixie Kiefer flew the plane off the USS. California in San Diego harbor. 

The only illumination came from the ship’s searchlights trained 1,000 yards ahead.

In 1924, Vought rang up its first foreign sale, twelve aircraft to Cuba. 

These airplanes were designated QO-1. 

Also, in that same year, Peru purchased two airplanes which were designated UO-1A

The Coast Guard procured two UO’s as UO-4’s in 1926, which were among the first aircraft bought for that service. 

These incorporated the new wings of the FU’s, plus the J-5 engines, and were used for chasing rum-runners off the coast during prohibition.

At one time in its lighter-than-air program, the Navy considered basing several fighters in internal hangars of dirigibles. 

These fighters would provide protection for the dirigibles against aerial attack. 

The Vought UO-1 was the first airplane to be picked up on a hook in midair from the Navy dirigible U.S.S. Los Angeles in 1929.

While O2U Corsairs were replacing the UO’s in the fleet, NAF was modifying the remaining UO-1’s and UO-1C’s and re-designating them as UO-5’s. 

This modification consisted of replacing the Lawrence J-1 engine with the Wright J-4 engine and increasing the wing span, and fuselage length and height. 

This rounded out their service in fleet support and training duty.  By 1933, the Navy UO’s were retired

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