Today we’re taking a look at the Avro 549 Aldershot.
This was Avro’s first entirely new post-war military aircraft, and it was built as a long-range,
single-engine heavy bomber.
Following the end of the first world war, the idea of single engine bombers had become
quite popular with the British Air Ministy.
It was a time of economic strife, and they were looking for ways to maintain a strong
bomber force that wouldn’t cost a small fortune to produce and maintain.
The easiest solution to this was to reduce the number of engines, and with the advent
of newer powerplants this was now possible.
Because of this, the Air Ministry issued specification 2/20, which called for a large, single-engine
bomber, with a range of 500 miles (or 804 km), and a bombload of 2000 lbs (or about
900kg).
To meet this specification, Avro designer Roy Chadwick drew up plans for what would
become the Aldershot.
Powered by a single 650hp Rolls Royce Condor III, the Aldershot was notable as being the
first Avro aircraft to feature a metal fuselage structure; the rear of this fuselage was clad
in doped fabric, and the front section was covered in plywood.
It was deep enough that it accommodated a double-deck cabin; A 210-gallon fuel tank
was located ahead of the cabin and the lower half of the nose formed a radiator compartment
into which cooling air was admitted through controllable shutters.
It had three-bay, slightly swept, folding wings; They were of wooden construction and
fitted with large differential ailerons, and were aerodynamically balanced by ‘park bench’
aerofoils on the upper set.
For a single-engine aircraft, the accommodation for the crew was considered especially spacious.
Two pilots sat side-by-side on the upper deck, within a dual-control cockpit; behind them
in his own cockpit was the rear gunner, who had a scarf-mounted Lewis Gun; and below them,
via a small access ladder, was the cabin that housed the bomb aimer and radio operator.
For some reason, sources seem to conflict on the crew compliment.
Some claim it to be as little as three, in fact, Wikipedia even claims this number, but
after reviewing several documents, and looking at the layout of the Aldershot, I believe
the total number was five.
Two pilots, a gunner, the radio operator, and the bomb aimer.
In a pinch, it could be operated by four, with the gunner also operating the radio,
but I can’t say for certain if this was ever done in practice.
For combat operations the Aldershot was built to be moderately defended, and to carry a
large payload.
A high set, variable incidence tailplane gave the gunner a clear field of fire over and
around the tail surfaces; the aircraft also came with a forward firing machine gun, though,
like many of this time, its underside was completely vulnerable.
This underside held a very wide track undercarriage, which was divided so that a single heavy bomb
could be carried beneath the fuselage.
At the beginning this was the World War One-era, 1800 lb SN high explosive bomb, though this
arrangement would change later.
As a quick side note on the armament: Later on there appears to have been provision made
for a ventral machine gun, but how often this was actually used is difficult to tell.
There are drawings that show it, though I’ve struggling to find any photo evidence of the
gun being installed, so I’m going to leave it as a tentative maybe
The Aldershot came in three distinct forms, the Adlershot 1, 2, and 3.
Though only the latter represented actual production models, with the first iterations
being prototypes.
Two prototype Mk 1s were built as the original entrants for the air ministry’s proposal,
competing directly with the De Havilland Derby.
The first of these flew for the first time in October 1921, with test pilot Bert Hinkler
at the controls.
Early flights revealed that the rudder was excessively heavy, resulting in minimal lateral
control, and this made take off and landing a little bit nerve racking for Hinkler.
To address this, the dorsal fin was removed and a new rudder was installed with a large
balancer, but this only partially solved the problem.
The solution ended up being the extension of the fuselage itself by about six feet,
which necessitated a return to the workshop and a protracted delay in flight testing.
But it worked, and Hinkler reported that the aircraft was far more stable during take-off,
and in flight, and the rudder now felt far more effective.
The Aldershot then made its public debut at the 1922 RAF Display at Hendon.
For a single engine aircraft, it was deeply impressive, but its size hid the fact that
it was also fairly quick and manoeuvrable for an aircraft of its bulk.
By today’s standards, a top speed barely in excess of 100mph or 160 kmh may seem slow,
but for a single engine biplane in 1922, and one that weighed four and-a-half tons when
loaded, it was an impressive performer.
This was then confirmed when it won the handicap race held during the air display itself, which
even surprised the Aldershot’s designer.
Following Hendon, the first prototype Aldershot went back to the workshop for a major upgrade
(almost nothing is known about the fate of the second).
It received one the six experimental Napier Cub engines.
This was a 60 litre, 16-cylinder engine, weighing over a ton that produced 1,000hp.
Only six of these massive powerplants were built, and the only other aircraft to make
use of it was the Blackburn Cubaroo, which we’ve already covered on this channel.
This vast powerplant drove a large, four-blade propeller, and it was so impressive that it
required a re-design of the engine mounts, the reinforcements of almost the entire airframe,
and the installation of a double undercarriage.
Owing to the drastic design changes, the aircraft was re-designated as the Aldershot mk II.
It flew for the first time, amid considerable publicity, and in the presence of the Vice
Air Mashal and A.V.
Roe himself, on the 5th of December 1922.
Considering it had almost two tons added to its weight by the engine and various reinforcements,
the Aldershot performed remarkably well.
It took off from the field at Hamble after a mere three seconds, and after getting a
feel for the controls, Hinkler threw it about with considerable enthusiasm.
During his little display he supposedly achieved 140mph in a downward pass over the spectators,
after which he came down for a smooth landing at a speed that seemed impossibly slow for
the aircraft to handle safely.
Hinkler was suitably impressed by its performance and said that its stability during flight
made it remarkably forgiving, even with the roughest of control inputs.
After its first flights at Hamble, the Aldershot II went to the Royal Aircraft Establishment
at Farnborough in January 1923.
It spent the first half of the year completing various flights, tests, and experiments; some
concerning the aircraft; some more specific to its engine.
After attending the Hendon Display that year it was then shipped off to Sweden for the
Gothenburg Aero Exhibition, where it dwarfed all other aircraft on display there.
After this it spent the next few years as either a research aircraft, or as an attraction
at public displays.
The rest of 1923 was spent at the RAE Engine Research Flight, where more data was gathered
on the performance of the Napier Cub, and after this it was used for a long series of
experimental trials.
Four years later, in 1927, it was re-engined with the Beardmore Typhoon, which was even
more experimental than the Napier Cub.
This was huge a six-cylinder engine that displaced 68 litres, and was designed to provide high
power at low revolutions – to the tune of 850 to 950 hp.
Equipped with this new engine, the aircraft was known as the Avro 549C, or the Aldershot
Mk IV, and it was flown experimentally from the 10th of January 1927 until it was finally
retired and scrapped, the date of which is unknown.
Unlike many experimental aircraft from this period, the Aldershot was lucky enough to
be put into production as well, albeit on a limited basis.
Back in 1923, the Aldershot had been impressive enough for the Air Ministry to place an initial
production order for fifteen aircraft.
Unfortunately, the Napier Cub proved to be a short-lived experiment, and these new Aldershots
were to be powered by the same Rolls Royce Condor III as the original design proposal.
Though much of the design was similar to the original Aldershot, there were some changes
made to bring it up to standard for the RAF.
To cope with rough take-off and landings, the Aldershot received a multi-strut, reinforced
undercarriage; the bombload was now to be carried internally, normally comprising of
twelve 200 lb bombs, or in place of this, two torpedoes could be suspended below the
fuselage between the landing wheels; and as the weight had crept up, additional fuel tanks
were added to the upper wing to increase its range.
The armament remained the same, as was the crew compliment of five, and there seems to
be some indication of upgraded equipment within the main cabin as well, though I’ve struggled
to confirm this.
Completed as the Aldershot Mk III, these aircraft entered service with No.99 Squadron on April
the 1st 1924.
The Aldershot’s exceptional stability made them well suited to nighttime operations,
and in consequence of this many of 99 Squadrons operations were done at night.
This was fairly uncommon for an aircraft of this size, as this sort of flying was still
considered highly risky at the time, but the Aldershots excelled in their role, and they
quickly earned a good reputation with their crews.
Unfortunately, the Aldershot was a victim of its own design.
In 1925, the Air Ministry abandoned its policy of producing large, single engine bombers
in favour of multi-engine designs once again.
This was for multiple reasons: safety, reliability, range, power, higher payload, but it all amounted
to the same thing: the Aldershot was doomed.
They only served with 99 Squadron for two short years, all of which were peaceful, and
the aircraft never really got to display its qualities, with the exception of a few mock
bombing runs during various training exercises.
One of the Aldershot’s last major outings was to fly at the Hendon Air Show in 1925,
where the entire squadron flew in formation – which would have been an amazing sight,
but it was also the last time they would do so.
In January 1926, the squadron refitted with Handley Page Hyderabads, and the Aldershots
short career came to an end.
Not much is known about what happened after this, but seeing as nothing of them survives
today, its safe to assume they were scrapped at some point in the mid-to-late 1920s.
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