The Type 175 began as a Medium Range Empire (MRE) design to meet BOAC requirements set down in MoS Specifica¬tion 2/47.
Designed to carry 32-36 passengers and be powered by four Bristol Centaurus 662 sleeve-valve engines, the aircraft’s size was soon increased and consideration given to the installation of Bristol Proteus turbines or Napier Nomad compound engines.
After some delay, in June 1948 the Ministry of Supply ordered three Centaurus-powered prototypes but stipulated that the second and third should be capable of conversion to Proteus-engined aircraft. When the first prototype emerged in 1952 it was a much bigger aeroplane with accommodation for more than 80 passengers and powered by Proteus 625 engines.
Prototypes were ordered in February 1948 and the first of these was airborne at Filton on 16 August 1952, powered by Bristol’s new Proteus turboprop.

Bristol B.175 Britannia Article

The second prototype was lost after only 51hr flying and a major engine fault delayed entry into service with BOAC until February 1957. On 1 February 1957 BOAC began operating Britannia 102 with 2,906kW Proteus 705 and up to 90 seats on its London-Johannesburg services.

A number of versions were developed from the Series 100 aircraft and on 19 December 1957, BOAC began the first turbine-powered North Atlantic service when it put Britannia 312 on the London-New York route. These were 3.12m longer, had accommodation for up to 139 passengers, were powered by 3,070kW Proteus 755 and had a 13,608kg increase in max weight. On the day that BOAC introduced Britannias on the North Atlantic, El Al flew a Britannia 10,328km non-stop from New York to Tel Aviv.

The Bristol Britannia entered RAF Transport Command service with No.99 Squadron, at Lyneham, Wiltshire, in mid-1959. As Britannia C.1, twenty Britannia 250 were operated with strengthened floor and large freight loading doors. Three Britannia C.2s were purchased by the Ministry of Supply for use on trooping flights.

The Britannia 310 was ordered by BOAC, El Al, Hunting Clan, Canadian Pacific Airlines and Cubana.

Only 85 Britannias were built at Filton and by Shorts at Belfast.

Canadair developed the Britannia design into the military CL-28 Argus and CL-44 Yukon and the CL-44 series of passenger and cargo aircraft.

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Variants:

100 Series
90 passenger airliner
All built at Filton
Engines: four Bristol Proteus 705, 4,400 h.p.
Length: 114 feet
Height: 36 feet 8 inches
Wing Span: 142 feet 3 inches
Weight (empty): 88,000lbs
Weight (all-up): 155,000lbs
Range: 3,450 miles

101 – Two prototypes, initially powered by Proteus 625, later 705
102 – 25 ordered by BOAC. The last ten were cancelled in favour of the 300 series.

200 Series
All-cargo stretched version of the 100 series, with an extra 10 ft in length.
Five options from BOAC, but cancelled in favour of the 310. None built.

250 Series
As 200 series, but mixed passenger and freight
Length: 124 feet 3 inches
Height: 37 feet 6 inches
Wing Span: 142 feet 3 inches
Weight (empty): 90,500lbs
(90,600lbs for 253)
Weight (all-up): 185,000lbs
Range: 2,268 miles

252 – Three ordered by Royal Air Force and given the designation C Mark 2. All built at Belfast.
253 – 22 ordered by Royal Air Force, with designation C Mark 1. All but the last five were built at Belfast, the remainder were built at Filton

300 Series
As 200 series, by passenger only. Capable of carrying up to 139 passengers.
Engines: 4 x 4,400 h.p. Bristol Siddeley Proteus 705 turboprop
Length: 124 feet 3 inches (37.89 m.)
Height: 37 feet 6 inches
Wing Span: 142 feet 3 inches (43.38 m)
Weight (empty): 92,500lbs
Weight (all-up): 185,000lbs
Econ cruise: 355 m.p.h. (570 kph)
Range: 3,496 miles
Range 4,268 miles (6,869 km.) with max. payload of 28,000 lb (12,700 kg)
Crew: 9
Pax cap: 133

301 – one prototype, built at Filton
302 – Ten ordered by BOAC. Order cancelled in favour of 305 Series, later 310 series. Two were completed, but not delivered. Both were built at Belfast.

305 Series
As 300, but with increased fuel capacity
Length: 124 feet 3 inches
Height: 37 feet 6 inches
Wing Span: 142 feet 3 inches
Weight (empty): 90,000lbs
Weight (all-up): 185,000lbs
Range: 4,268 miles

306 – 1 built, leased to El Al. built at Belfast
307 – 2 ordered by Air Charter. One was a conversion of the sole 306, the other was built at Belfast.
307F – 1960’s conversion of 307 to freighter (both Series 307 aircraft converted)
308 – 2 ordered by Transcontinental, built at Belfast.
308F – 1960’s conversion of 308 to freighter (both Series 308 aircraft were converted)
309 – 1 ordered by Ghana Airways, built at Belfast.

310 Series
Initially known as 300LR. As 305 series, but with strengthened fuselage skin and undercarriage.
Engines: 4 x Bristol Proteus, 4120 shp
Length: 124 feet 3 inches (37.89 m)
Height: 37 feet 6 inches
Wing Span: 142 feet 3 inches (43.38 m)
Weight (empty): 82,500lbs
Weight (all-up): 185,000lbs
Range: 4,268 miles
Max level speed: 385 mph (616 kph)

311 – one prototype, built at Filton.
312 – 19 ordered by BOAC, all built at Filton.
Engine : 4 x Proteus 755, 4064 shp
Length: 124.245 ft / 37.87 m
Height: 37.5 ft / 11.43 m
Wingspan : 142.224 ft / 43.35 m
Max take off weight : 185030.4 lb / 83914.0 kg
Max. speed : 345 kts / 639 km/h
Service ceiling : 26247 ft / 8000 m
Range : 5004 nm / 9268 km
Crew : 5 + 133 PAX

312F – 1960’s conversion of 312 to freighter (five converted)
313 – Four ordered by El Al, all built at Filton.
314 – Six ordered by Canadian Pacific, all bar one built at Belfast.
317 – Two ordered by Hunting-Clan Air Transport, all built at Filton.
318 – Four ordered by Cubana, all built at Filton.
320 Series – as Series 310, with a few modifications, giving increased maximum range.
Length: 124 feet 3 inches
Height: 37 feet 6 inches
Wing Span: 142 feet 3 inches
Weight (empty): 86,400lbs
Weight (all-up): 185,000lbs
Range: 4,268 miles

324 – Two ordered by Canadian Pacific

A Breguet designed four-engined STOL transport that would be suitable for civil or military use the Bre.941 relied upon the deflected-slipstream technique to generate additional lift. The four engines were mounted in nacelles at the wing leading edges so that slipstream from the propellers was distributed over the entire span of the wing.

Only 17% prop thrust is lost should one of the four 1250 shp Turbomeca Turmo IIID shaft turbines fail during takeoff since all props remain operative. Four 13 ft 8.5in diameter Ratier-Figeac hydraulically operated variable pitch fully reversible propellers provide airflow across the full 76 ft 1 in wing span. High-lift for slow speed is obtained by deflecting the slipstream with full span double-slotted flaps that work through 100 degrees, plus four hinged spoilers on each wing. Ailerons which extend across 42% of wing also droop for STOL operation.

Full-span double-slotted trailing edge flaps were provided, these also being within the slipstream when deployed to maximise their effect, and with no wing trailing edge available for ailerons to be installed for roll control, four hinged spoilers were provided on the upper surface of each wing.

Once power settings of the four engines are made by individual controls, uniform rpm is maintained by the co-pilot’s single long-arm throttle at the right of the console. In the pilot’s position duplicate master throttle is to the left of seat. Downward visibility windows are on each side of cockpit at end of instrument panel. Main landing gear which retracts into fairings on each side of fuselage is the Messier “Jockey” trailing arm design where two wheels of each unit are hydraulically interconnected. This provides wheel movement in both fore-and-aft and vertical directions for rough terrain operations.

The French air ministry ordered a prototype on 22 February 1960. It was of cantilever high-wing configuration, with an upswept rear fuselage to incorporate a rear loading ramp. Undercarriage was retractable tricycle landing gear that incorporated twin nosewheels, with tandem-wheel main units that retracted into fairings on each side of the fuselage. Powerplant was four 895kW Turbomeca Turmo HID turboprops, and the prototype was flown for the first time on 1 June 1961. Subsequent testing of the prototype resulted in Breguet receiving a contract from the French government for the supply of four production transports under the designation Breguet 941S.
Production aircraft were fitted with more powerful Turbomeca Turmo engines, a longer nose to permit the installation of a large radome, and modification of the rear cargo door to allow for the airdrop of heavy loads.

Operated by a crew of two, these aircraft could carry up to 57 civil passengers, or 40 fully-equipped troops, or 24 stretchers. The first of the production Br.941S aircraft made its initial flight on 19 April 1967, and testing proved that with an all-up weight of 22000kg, which was in excess of an assault mission take-off weight, the Br.941S could become airborne in only 185m.

All four of the production aircraft entered service with the Armee de I’Air, but no additional examples were built. There had been hopes that, with assistance from the McDonnell Aircraft Corporation, orders might be generated in the USA, but despite a demonstration tour in America, no production orders were received.

As there was a possibility the 941 may be made under licence in the US, during the 1969 demonstration tour it was designated McDonnell 188.

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Engines: 4 x Turbomeca Turmo III D-3 turbo-prop, 1105kW
Wingspan: 23.4 m / 76 ft 9 in
Length: 23.8 m / 72 ft 11.5 in
Height: 9.4 m / 30 ft 7 in
Wing area: 83.4 sq.m / 897.71 sq ft
Take-off weight: 26500 kg / 58423 lb
Empty weight: 13120 kg / 28925 lb
Max payload: 15,000 lb
Max. speed: 520 km/h / 323 mph
Max speed at 10,000ft: 280 mph
Cruise speed: 480 km/h / 298 mph
Stall: 56 mph
Ceiling: 8500 m / 27900 ft
Range w/max.fuel: 3100 km / 1926 miles
Range w/max.payload: 800 km / 497 miles
Landing dist: 360 ft
Crew: 2
Passengers: 55-60

Breguet Bre.940 Integraal Article

The experimental Bregeut Br.940 first flew on 21 May 1958. For STOL operations, it is fitted with camber-changing slotted flaps, and large diameter, slow turning propellers driven by Turbomeca Turmo II turboprops.

The Br.940 was the prototype for the Br.941 series production.

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