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Bristol
TB8 and GB75

A very successful biplane conversion of the Bristol Coanda Military Monoplane.
Bristol Coanda TB8 proto no121 The first Bristol TB8 was a conversion of Military Monoplane c/n 121 to biplane configuration.
 
After the temporary Royal Flying Corps ban on the use of the monoplane, Coanda turned his attention to a series of two seat biplanes. This entry covers the Bristol Coanda TB.8 and GB.75 models whilst separate entries are provided for the Bristol Coanda BR.7 biplane and the Bristol Coanda Hydro elsewhere on this website.
 
Bristol Coanda TB.8
The Admiralty ordered a land plane derived from the Coanda monoplane, the prototype being a conversion of the monoplane (No. 121). This was tested at Larkhill from July 1913 and proved much superior to the BR.7.
 
This first aircraft, designed by Romanian Henri Coanda, was subsequently converted to a twin float configuration as the 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 Hydro down the middle. A steerable tail float and a ventral fin were also added. Early aircraft utilised wing-warping although later production models were fitted with ailerons.
 
The TB.8H was tested successfully at Dale, Milford Haven from 20th September 1913.
 
Bristol Coanda TB8 twin float trials Dale No 121 The first Bristol TB8 was flown as a seaplane at Dale in September 1913.
 
The 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 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.
 
Bristol Coanda TB8 1216 Eastchurch Mar 1915 Bristol Coanda TB8 1216 (build number 332) in service at Eastchurch in March 1915.
 
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 50hp Gnome (serials 8442-9) or 60hp Gnome (serials 8450-3 and 8562-70) engines. A final three aircraft (8571-3) were delivered to store.
 
In total, 54 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 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 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.
 
Bristol Coanda TB8 GB75 601 - should be 610 The sole Bristol Coanda GB75 (build number 223) was a redesign of the TB8.
 
A final Coanda design 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.

 

Specifications

  TB.8 (TB.8H) GB.75
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)

Survivors

No examples survive.

Other information