After the temporary Royal Flying Corps ban on the use of the monoplane, Henri Coanda turned his attention to a series of two seat biplanes. These included Bristol Coanda TB.8 and GB.75 models as well as the Bristol Coanda BR.7 biplane and the Bristol Coanda Hydro .
Bristol Coanda TB.8
The Admiralty ordered a land plane derived from the Coanda monoplane, with the prototype being a conversion of the monoplane (No. 121). It was tested at Larkhill from July 1913 where it proved much superior to the Bristol Coanda BR.7.
This first aircraft, designed by Romanian Henri Coanda, was subsequently converted to a twin float configuration as the Bristol TB.8H. It was delivered to the Admiralty at Calshot as a replacement for the unlucky Bristol Coanda Hydro 120.
The twin floats were produced by the simple remedy of cutting the original Gnosspelius float of the Bristol Hydro Monoplane down the middle. A steerable tail float and a ventral fin were also added and whilst early aircraft utilised wing-warping, later production models were fitted with ailerons.
The Bristol TB.8H was tested successfully at Dale, Milford Haven from 20th September 1913.
The Bristol TB.8H was rebuilt with a new fuselage in December 1913 as build number 205 and was delivered to the Royal Naval Air Service with serial number 15 (as originally intended for the Bristol Coanda Hydro).
The Bristol TB.8 was an immediate success and ten of the earlier monoplanes (previously delivered to Italy, Germany and Rumania) were brought back for conversion to biplanes. A new-build production (starting with number 197) commenced with sales to France resulting in additional production by the Breguet concern.
Wartime production included 12 aileron-equipped aircraft which were delivered to the RNAS as Nos 1216 to 1227. Another 24 aircraft were built for training purposes with either the 50hp Gnome engine (serials 8442-9) or 60hp Gnome engine (serials 8450-3 and 8562-70). A final three aircraft (8571-3) were produced but these were delivered to store.
In total, 54 Bristol TB.8 were built.
One of these aircraft was the April 1914 conversion of a side-by-side Bristol Coanda monoplane (build number 177) and became the sole side-by-side example of the TB.8 (build number 218).
Bristol Coanda GB.75
The next Coanda designed two-seat biplane was the Bristol GB.75 (build number 223) which was designed for Romanian use. It featured a more streamlined fuselage with a large rounded propeller spinner fairing into the lines of the fuselage.
The type flew for the first time on 7th April 1914, whilst the large spinner was later removed following trials.
Subsequently, the Romanian order was cancelled although the aircraft concerned was delivered on 2nd August 1914, for use by the Royal Flying Corps (RFC) and fitted with a standard 80 hp Gnome engine. It was allocated serial 610 but spent some of its time displaying the incorrect serial 601.
A final Coanda designed for Bristol was the PB.8 pusher biplane and although this was built (at low priority) as a Boxkite replacement. Despite being completed it never flew due to its engine being requisitioned by the War Office.
|Powerplant||80 hp Gnome also 80 hp Le Rhône, 100 hp Mono-Gnome, 50 hp Gnome or 60 hp Le Rhône||75 hp Mono-Gnome, 80hp Gnome|
|Span||37 ft 8 in||37 ft 8 in|
|Maximum Weight||1,675 lb||1,650 lb|
|Capacity||Two seat||Two seat|
|Maximum Speed||65 – 75 mph||80 mph|
|Endurance||5 hr (4 hr)||5 hr|
Variants and number built
|TB.8 and TB.8H||Fifty-three TB.8 and one TB.8H: build numbers: TB.8 118, 121, 143, 144, 147-9, 151-3, 196-8. 218, 225, 227, 228, 331-342, 870-893. TB.8H 205|
|GB.75||One only, build number 223|
|Total||Fifty-four aircraft (including conversions from Coanda Monoplanes)|