Bristol T.B.8

Bristol Aeroplane Company
Industry	Aerospace
Founded	1910; 116 years ago
Founder	Sir George White
Headquarters	Bristol, United Kingdom
Products	Aircraft, including the Bristol T.B.8

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The Bristol T.B.8, also known as the Bristol-Coanda T.B.8, was an early British biplane produced by the Bristol Aeroplane Company and designed by Romanian engineer Henri Coandă. A total of fifty-four units were constructed, primarily serving as trainers. A limited number of these aircraft were briefly deployed in a bombing role by the Royal Naval Air Service at the outset of World War I.

Design and development

The Bristol T.B.8 originated as a biplane adaptation of Henri Coandă’s earlier Bristol-Coanda Monoplane design. As chief designer for the Bristol Aeroplane Company, Coandă created this conversion to satisfy an order placed by the British Admiralty. The aircraft’s maiden flight occurred on 12 August 1913. It underwent trials equipped with both wheeled undercarriage and floatation gear.

This model was a two-seat biplane powered by a single rotary engine, featuring two-bay wings and a slim fuselage profile. It accommodated several rotary engine variants, including those from Gnome and Le Rhône, with power outputs ranging from 50 hp Gnome units to the more powerful 100 hp Gnome Monosoupape engines. Early versions employed wing warping for roll control, while later production models incorporated ailerons. The T.B.8 typically featured a distinctive four-wheel undercarriage arrangement. Production involved both converting existing Bristol-Coanda Monoplanes and building new airframes from scratch.

File:TB8 bombs.jpg

The Bristol T.B.8 equipped with a cylindrical bomb carrier

One particular Bristol T.B.8 was outfitted with a prismatic bombsight mounted in the forward cockpit and fitted with a cylindrical bomb rack beneath the front fuselage. This rack could carry up to twelve bombs weighing 10 lb (4.5 kg) each, which could be released individually or in salvo formation according to operational needs. This variant was exhibited at the Paris Salon de l'Aéronautique and evaluated by French military authorities before being acquired by the Royal Naval Air Service.

Operational history

The Bristol T.B.8 was acquired for deployment by both the Royal Naval Air Service and the Royal Flying Corps. Shortly after World War I began, the Royal Flying Corps transferred its Bristol T.B.8s to the Royal Naval Air Service. Following the war’s outbreak, three Bristol T.B.8 aircraft—including the one showcased at the Paris Air Show in December 1913—were dispatched to France to operate within a Royal Naval Air Service squadron under the leadership of Charles Rumney Samson. On 25 November 1914, one of these aircraft conducted a bombing raid targeting German artillery positions at Middelkerke, Belgium. This mission marked the sole bombing operation executed by the Bristol T.B.8. Due to its limited speed, the aircraft was deemed unsuitable for frontline combat and consequently reassigned to training duties, where it remained in service until 1916.

Variants

G.B.75: The Romanian authorities expressed satisfaction with the Bristol T.B.8 and commissioned an enhanced model powered by a 75 hp (56 kW) Gnome Monosoupape engine. This version, named the G.B.75, featured notable visual differences, including a sleeker nose section and a rounded engine cowling that enclosed the rotary engine. The distinctive Coanda fin was replaced by an unbalanced rudder combined with a fin. Its top speed improved to 80 mph (130 km/h). The aircraft's maiden flight occurred on 7 April 1914, during which modifications such as spinner removal and increased wing stagger were made to optimize center of pressure balance. Although these changes were implemented, the G.B.75 was declared operational by June 1914. However, these modified aircraft were requisitioned by the Royal Flying Corps at Farnborough before delivery to Romania and were equipped with standard Gnome engines.

T.B.8H: One Bristol Coanda Monoplane was converted into a prototype for the T.B.8 series and outfitted with twin floats, resulting in the T.B.8H "Hydro" variant.