Bristol 170 Info & Specs

A Brief History….

Often referred to as the ‘Biffo’, ‘20,000 rivets flying in close formation’ or a number of other less savoury names, the rough yet ready Bristol 170 was invariably seen as a basic, no frills, short range airliner that by virtue of its simplicity turned out to be tough, utilitarian and extremely reliable by the standards of the time. Its origins however derived from those of a military nature, with these venerable aircraft initially being designed with nothing, but the transport of a three ton British Army truck in mind. In their attempt to meet these specifications, Bristol would at first select the Pegasus engine as a power plant; however, it was the more powerful Bristol Hercules that would ultimately reign supreme and as such, the selection of these engines would enable the B170 to lift an extra 1.5 tonnes of payload.

So, on December 2nd 1945 the prototype B170 (G-AGPV) took to the air. The aircraft was considered to be a relatively stable platform with reliable in-flight characteristics, the only note of concern being the lack of trim which was later corrected by repositioning and slightly enlarging the rear, horizontal stabilisers with such an improvement quite naturally being carried over to the production line. With production now in full swing, Bristol would on occasion seek to outsource work to other companies and it was at this point that a Southend based firm would come into the picture. Having already proven its conversion and engineering credentials during the Berlin Airlift, Aviation Traders would be offered a contract to build the centre wing sections for around 50 Bristol 170s. Such familiarity with these aircraft would also later become useful when ATEL carried out a number of conversions including one, Mk32 upgrade for their airline wing Air Charter.

While several different options would be offered over the coming years, there were three main variants, each having its own distinct name. These were known as the Bristol ‘Freighter’, this being the standard, short nosed model with clamshell nose doors that could in air ferry service, carry two cars and up to 20 passengers. While the second Bristol ‘Wayfarer’ version looked very similar, it was for passenger use only lacking the clamshell doors, although these were later added to the E variants both of which could carry as many as 53 passengers in a high density layout. Finally, came the lengthened Mk32 or ‘Superfreighter’ variant, all of which were equipped with extended nose doors that added an extra 5ft to the length of the aircraft. This modification enabled the vehicle ferry operators of the time to transport three medium sized cars and a maximum of 23 passengers.

Indeed, if anyone was to query the more mature aviation enthusiast about their memories of this aircraft, then most would no doubt relate tales of those heady days of the prime B170 operators, Silver City and Channel Air Bridge, both of which played their part in making the cross-Channel vehicle ferry routes some of the most highly trafficked in the world during the late 1950s and early 1960s. Sadly though, such halcyon days were not to last and as British, cross-Channel shipping operators began to bite severely into the profits of these airlines, services that were operated with the B170 would more increasingly fly at a loss before inevitably becoming completely untenable.

While Channel Air Bridge, British United Air Ferries and later BAF managed to temporarily stave off maritime competition for another decade or so with the larger, purpose built Carvair, the days of the Bristol 170 on these routes were well and truly over. With a glut of more efficient turboprop and jet airliners now taking pride of place within the fleets of most airlines, the trusty Biffo would more increasingly find herself being relegated to freighting tasks. By the mid-1970s, most of these aircraft had been removed from the British register, although thanks to their ability to deliver rough field performance, a small number of them would find their operational lives being extended, flying between remote and often unmade airstrips in Canada and New Zealand.

As far as figures go, the B170 can easily be considered as being one of the British aviation industry’s more successful products with Bristol finally producing a total of 214 airframes and yet despite this aircraft’s rather important place in the annuals of British aviation history (especially the car-ferry era), somewhat unbelievably, not a single aircraft was set aside for preservation in the U.K. Somewhat thankfully however, one of these aircraft (Mk31 NZ5911) is now due to return to the U.K. for preservation at Filton while our Canadian, Australian and New Zealander cousins have managed to save a total of eight Mk21/Mk31 aircraft between them. However, the oldest surviving example (a MkI version), resides in the National Aircraft Museum in Buenos Aires, Argentina.

 

Bristol 170 Main Variants

Mk I Freighter

Basic variant for B.E.A.

Mk II Wayfarer

Wayfarer version with passenger cabin for 20-32 pax

Mk 21 and Mk21E Freighter

Uprated engines while E version Wayfarer interchangeable between passenger and freight configuration

Mk31 and Mk31E Freighter

Larger rudder – E version as above

Mk 32 Superfreighter

Lengthened variant (1.5m) for mixed car/passenger ferry services

 

Specifications

Number Built

214

Type

Mixed Pax/Cargo

Length

68ft 4in (20.88m)

Mk32 – 73ft 4in (22.40m)

Wingspan

108ft (35.82m)

Configurations

Mk I to Mk 31

2 cars + 20 pax

1 car + 1 ton of freight + 32 pax

53 pax

or

4.5 tons of cargo

Mk 32

3 cars + 23 pax

60 pax

or

4.5 tons of cargo

Cruise Speed

169kt – 195mph (315km/h)

Ceiling

24,500ft (7,468m)

Range

490m with a 2 ton load (789km)

Engines

2 x 1,675/1,690/1,980hp – Bristol 632/672/734 Hercules 14 cylinder radials