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Supermarine Baby

The Supermarine Baby (also called the Supermarine N.1B Baby) was a First World War fighter aircraft that was the earliest example of single seat flying boat fighter to be built in the United Kingdom.

It was designed by Supermarine to meet a 1917 Navy Board specification which stipulated the aircraft have a speed of 95 knots (176 km/h; 109 mph), a ceiling of 20,000 feet (6,100 m), and be capable of being launched from ships at sea.

When it first flew in February 1918 it was the smallest and fastest flying boat then in existence.

Supermarine’s chief designer William Hargreaves based his design on the AD Flying Boat.

The Baby was given folding wings, a streamlined hull and a 150 horsepower (110 kW) Hispano-Suiza engine.

A single aircraft was built by the company which performed well during trials, and the aircraft was fitted with a more powerful engine in August 1918.

A production contract was not awarded, as the Admiralty decided to operate the Sopwith Pup and Sopwith Camel fighters from aboard ships.

One of the designs for the Baby formed the basis for other aircraft, including the Supermarine Sea Lion I which participated in the 1919 Schneider Trophy.

Supermarine’s future chief designer Reginald Mitchell was probably involved in the Sea Lion’s design and preparation for the contest.

The prototype was given the serial number N59 and first flew after its completion in February 1918.

During trials, it handled well and proved to be fast and manoeuvrable, but showed a tendency to ship water into the cockpit when it accelerated.

Hargreaves responded to this problem by producing at least six alternative designs for the hull. 

In August 1918, the aircraft was fitted with a more powerful Sunbeam Arab 200 horsepower (150 kW) engine.

The smallest and fastest flying boat then in existence, its evaluation was completed just prior to the Armistice of 11 November 1918.

The performance of the Baby was good enough for a production contract to be awarded, which was close to completion that November.

The Baby never saw action during the war.

By November 1918, the Royal Naval Air Service had already been using Sopwith Pup landplanes to fly off platforms aboard ships, and the success of the Pup was a factor, along with the end of the war, that caused the British government to cancel the N.1B program.

By this time, a second aircraft (named N60) had been built, which never flew. 

N60 was delivered as spare parts to support testing of N59.

A third machine (N61) had yet to be assembled, although the construction of the hull had begun, at the time the program was abandoned.





26 ft 4 in (8.03 m)


30 ft 6 in (9.30 m)


10 ft 7 in (3.23 m)

Wing area

309 sq ft (28.7 m2)

Empty weight

1,699 lb (771 kg)

Gross weight

2,326 lb (1,055 kg)


1 × Hispano-Suiza 8B, 

V-8 water cooled piston engine,

150 hp (110 kW)


4 bladed wooden fixed pitch pusher propeller

(The aircraft was subsequently powered with a 200 horsepower (150 kW) engine)


Maximum speed

116 mph (187 km/h, 101 kn)

Alighting speed

57 mph (50 kn; 92 km/h)


3 hours

Service ceiling

10,700 ft (3,300 m) 

Time to altitude

10,000 ft (3,050 m) in 25 minutes 10 seconds

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