Recently, we had a look at the history of the grotesquely ugly Avro Bison,
and today, continuing the trend of subjecting my audience to the visual horrors of such things,
we’re looking at the Bison’s equally ugly competitor: the Blackburn Blackburn.
Designed to meet the same Air Ministry specification for a reconnaissance and fleet
gunnery spotter, the Blackburn was named after the Lancashire town that bore the same name as
its manufacturer, much to the confusion of all. As with the Bison, functional considerations took
absolute priority during the design process of the Blackburn, with the end result being that
both aircraft looked remarkably similar. That being said, there are some notable
differences between these two particularly ugly ducklings that are worth talking about.
Designed by F.A Bumpus, the Blackburn was a two-bay biplane built up from a frame of metal
and wood; like the Bison, the Blackburn was designed to be powered by the large,
450 hp 12-clylinder Napier lion, and its upper wing was mounted directly on the fuselage, but
unlike the Bison, it featured folding wings that made it easier to store aboard aircraft carriers.
It also had a reduced crew compliment compared to the Bison, having just three:
a pilot, a navigator, and the radio operator would also serve as the rear gunner.
To save on costs in the form of parts and time, the basic structure of the Blackburn
was based on that of the previously built, and only slightly less ugly, Blackburn Dart.
It used the same style of fuselage construction, with the central section forming the nucleus to
which a number of sub-assemblies were attached to form the complete airframe. Unlike the Dart,
however, the fuselage aft of the central section was built as a semi-monocoque and had a greatly
increased width to accommodate the cabin for the navigator and the radio operator-gunner.
Unlike the Bison, this cabin was less luxurious, at least in terms of heat preservation and
general comfort, rather than equipment. The rear of the cabin was open to the elements,
allowing for the installation of the rear gunner station, as well as a spot for the navigator to
use a sextant or handheld camera equipment. The enclosed part of the cabin, however, had
no windows at all, which made it feel very dark, cramped, and claustrophobic.
The pilot was equally exposed as the gunner, being sat in an open cockpit that was positioned within
a cut-out of the centre section of the upper wing. To provide good visibility, or at the very
least some visibility for carrier landings, the engine cowling sloped downwards at a sharp angle
which, like the Bison, gave the Blackburn the appearance of having a squashed nose.
The first prototype Blackburn was complete by mid-1922, and it flew for the first
time during the summer. Handling trials were then completed at Martlesham Heath,
beginning on the 12th of August, after which the prototype went on to Gosport to prepare for deck
handling trials aboard the carrier HMS Argus. The second prototype flew some months later,
the only modifications being a new undercarriage and the installation of an identical rudder to
that found on the Blackburn Dart. The Martlesham reports for the first two planes were somewhat
favourable; handling was considered acceptable, and the new undercarriage on the second prototype
was received favourable. However, there was complaints in the form of crew comfort;
the central cabin at the time lacked any windows and was considered morbidly dark,
and the exposed position of the pilot was considered draughty and uncomfortable…no
doubt an understatement for test flights done over the north sea.
All prototypes, particularly the second and third model, were also plagued with
the persistent problem of fuel surging. This led to the embarrassing forced landing of the third
prototype during its delivery flight to Martlesham before its official assessments had even begun.
Further testing found that take-off could only be accomplished with the tanks almost completely
full, and a solution to the problem was found by pressurising the tanks at take-off when they were
not running at full load. Unfortunately, the third prototype would not last long enough to see the
full effects of this change, as it was completely destroyed in a hangar fire in October of 1922.
Aside from the fire, and the fuel surging problem,
the Blackburn had a much smoother assessment period when compared to the Avro Bison, which
suffered from stability issues from the outset. In accordance with recommendations,
when the Blackburn entered production it had portholes installed to give the central cabin
some much needed light, which no doubt made for a less depressing ride for the radio operator,
and some further adjustments were also made to the fuel system.
Consideration was also made in using the Blackburn for torpedo duties, as some of
the first Mk I Blackburns had the fully divided undercarriage of the Blackburn Dark installed,
however it is unclear as to how many of these aircraft were actually tested with torpedoes.
They possessed a top speed of just 122 mph at 3000 feet, which, while faster than the Bison,
was not exactly a blistering pace,
and strapping a heavy torpedo underneath the fuselage would not have done it any favours.
The first twelve production aircraft were delivered in the spring of 1923,
with eighteen more of the Mk 1s following between 1923 and 1924. A notable feature on some of these
models was the addition of two streamlined fuel tanks which were installed on the upper wings.
The main fuel supply was carried in a saddle tank that sat behind the pilot, and below the centre
section of the wing. This placement meant that increasing its size, and therefore the range of
the aircraft, was impossible. The wing tanks increased the fuel capacity by 90 gallons,
though it is difficult to say how often these were installed. Only one or two photos seem
to exist showing this, which may indicate that their use was not a popular one, probably owing
to the increased drag that they caused. In 1925 a contract was placed for an
updated version of the aircraft, known as the Blackburn Mk II. Like the Avro Bison Mk II,
this aircraft had its upper wing raised above the fuselage on a series of short struts to
improve elevator performance. The additional fuel tanks on the wings were removed, the fuselage was
cleaned up to improve streamlining, and a simpler cross-axle undercarriage was
installed – indicating that the idea of using the Blackburn for torpedo bombing had been abandoned.
The Mk 1s had first entered service in 1923, joining 422 Fleet Spotter Flight aboard HMS Eagle
alongside a dozen Avro Bisons, and the Mk 2s first came into service in 1926,
replacing the Westland Walruses at Gosport. As they were designed for the same role,
the Blackburn and the Bison would often serve alongside each other abord the same aircraft
carriers, though the Blackburns were generally received with more kindness. This was not because
they looked any better, indeed on some angles they could almost be considered the uglier of the pair,
but it was rather because they just performed slightly better.
In ordinary weather, with the carrier steaming into the wind, the take-off distance was often as
short as 60 feet, and the Blackburn boasted better low speed handling when compared to the Bison.
It was also easier to store, owing to its folding wings.
Its popularity over the Bison is highlighted by the fact that a dual-control version of the
Blackburn was built as a training aircraft. At least two of these appeared to have been built,
and they were nicknamed the ‘Bull’ after earlier remarks that the Blackburn ‘was an apparatus with
the docile aspect of a bull in a field’, no-doubt much to the offence of any bovines within earshot.
Two Blackburns were also selected for experimentation as an amphibious aircraft,
and a pair of Mk 1s were modified to have a pair of floats installed in 1926. Though they
were apparently considered viceless in the air, the same could not be said for their seakeeping,
and after numerous landings that repeatedly ended in cracked or broken floats
the idea was mostly abandoned. The Blackburns enjoyed a slightly longer
service life when compared to the Avro Bison, but by the end of the 1920s their obsolescence was
becoming apparent, and they were finally retired from service in 1931. Like the Bison,
they would be replaced by the sleeker, more versatile, thought technically older Fairey IIIF,
which was a heavily upgraded version of a design that dated back to 1918.
However, unlike the Blackburn and the Bison, the Fairey was
far better suited to carrier operations, it could easily be converted to a floatplane,
and it was actually quite pleasant to look at. But the Fairey is a story for another day.
As always thank you so much for watching, and a big thank you
to the patreons. With a special shoutout to Kevin, Delliardo, Bane, FB, Christopher R,
Tronathon, Erik Hindman, John Austin Jr, Ray Culotta, Keith Tarrier, Greenseaships,
Northlincsweb, and MCT for their support as Wing Commander Tier Patreons.