The Navy Type 96, also known as the Mitsubishi Ka-14, and known more commonly in the west
as the A5M ‘Claude’, was a Japanese carrier-fighter built in the mid-1930s.
It was the product of a modernisation program to reduce Japan’s dependence on foreign equipment,
and it would become the world’s first monoplane carrier-fighter to enter service.
As with many Japanese aircraft of this time period, there are not a huge number of photos
available. And so, I shall be substituting some footage and screenshots from the game War Thunder,
which has a wonderful looking A5M4. In February 1934, the aviation headquarters
of the Imperial Japanese Navy issued a new specification for a single-seat fighter.
The document, known as specification 9-shi, did not specify that it should be a carrier-borne
fighter… just that it should be a fighter. Several influential officers, of whom Leftenant
Commander Hideo Sawai was the most vocal, believed that aircraft designed from the outset to operate
from carriers had performance defects, and that any fighter must be developed to be the
most effective combat aircraft it can be first, and only then would it be modified for carrier
operations. The problem of adopting a fighter for carrier operations was therefore kicked down
the road, and was only a matter to be addressed after a proper fighter had actually been built.
Because of this, the 9-shi specification only quoted the performance requirements. The new
fighter must 1) have a maximum speed of 350 kmh/h at 3000m.
2) climb to 5,000 meters in six-and-a-half minutes
3) have a wingspan and length not exceeding 11 meters and 8 meters respectively
And 4) it must have an armament of two 7.7mm machine guns.
Under the direction of Jiro Horikoshi, Mitsubishi’s team began work on a new prototype
to meet these requirements. The prototype, soon to be designated the Ka-14 was built around a
light-alloy monocoque with a flush-riveted aluminium stressed-skin. Special attention
was paid to aerodynamics and streamlining. A thin wing profile was selected, the fuselage was given
a small a cross-section as possible, and although a fixed undercarriage was used to save weight
it was covered by streamlined fairings. The ka-14 was powered by a Nakajima Kotobuki
9 cyclinder radial engine. It featuered a reduction gear and was rated at 550hp for
takeoff and 600hp at cruising altitude. It was selected over Mitsubishis own engine, the A-4,
as it was lighter without suffering any loss to performance or endurance.
The most recognisable feature of the Ka-14 was the elliptical inverted gull-wing,
which when viewed head-on can be compared to a W in shape. In the case of the Ka-14, this wing
shape was chosen as it was used in a previous specification to improve cockpit visibility
during landing. However, early in the prototypes development there were already concerns about
its effectiveness. There were reasons to believe that turbulent airflow would be generated by the
anhedral/dihedral transition, which would affect the overall flight characteristics of the plane.
Deciding to err on the side of caution, a second prototype -upon which construction
had already begun- was modified to be completed with a standard wing so that
the two models could be compared in the trials. Eleven months after the 9-shi specification was
issued, the first Ka-14 prototype was completed in January of 1935.
It flew for the first time on February the 14th, flown by Mitsubishi test pilot Kajima.
The take-off weight of the Ka-14 was 1,373kg, resulting in a wing loading of 77.2 kg per
square meter. This was considered rather high by Japanese standards, who valued lightness and
manoeuvrability. That being said, it was still significantly better than some other aircraft
that were making their first appearance – for example the first prototype Bf109 that
took off four months after the Ka-14 had a much higher wing loading of 117 kg per square meter.
The flight trials of the first prototype not only exceeded the expectations of the design team,
but they exceeded those of the 9-shi specification itself.
During further trials a maximum speed of 444 km/h was achieved at an altitude of 3200 meters,
eclipsing the performance of any other aircraft currently in the Japanese naval inventory.
Despite the success, there were still a couple of concerns raised by the test pilot. The Ka-14
suffered longitudinal oscillations at high angles of attack, and the plane had the nasty tendency
of trying to drop a wing during landing. Wing dropping on an airfield could be inconvenient
and sometimes dangerous -depending on the speeds involved- but wing-dropping on
approach for a carrier landing was a different level of risk altogether. And for this reason
it was hoped that the second Ka-14, the one with the straight wings, would perform even better.
At a late stage of construction, it was decided to add flaps to the centre section of this prototype
as a result of the aforementioned landing problems. The wing design also incorporated
a change that expanded laminar flow over the wingtip, which was hoped to improve stability at
high angles of attack. Problems with the reduction gear on the Kotobuki 5 engine were solved…by
replacing it with the direct-drive Kotobuki 3, and the plane was readied for testing.
Much to the relief of all, these modifications proved to be a sound investment. Despite
weighing 100kg more than the first prototype, the second Ka-14 had virtually the same performance
without any of the dangerous drawbacks. Because of this, the Army Air force also
expressed interest in Mitsubishi’s aircraft, and a single example was ordered under the designation
Ki-18. Though ultimately it did not impress the army enough for purchase – as even it did not
meet their borderline obsessive requirements for agility- it did spur them on to draw up a
new specification for an advanced fighter. They expected Mitsubishi would offer an extensively
modified version of their fighter, but as Mitsubishi were busy with preparing the Ka-14
for full production only a small team could be spared for the modifying the Ki-18 into the Ki-33.
As a result of this, Nakajima would win the Army competition with the Ki-27.
This was no great loss for Mitsubishi, who’s factory was filling up with fighters they were
merilly building for the navy, and considering the borderline hostile nature between Army and
Navy staff it was probably a blessing in disguise to not deal with the demands from both camps.
By late autumn of 1936, the Ka-14 had been approved for series production as the Type
96 Carrier-Borne fighter – also known as the A5M1. It was relatively similar to the second
Ka-14 prototype, however it featured a new engine cowling, the internal fuel tank capacity
had been increased, and the rear fuselage had been slightly re-designed to further improve stability.
It was also now powered by the Kotobuki 2 Kai A, which was rated at 580-hp for take-off.
Because of these airframe changes, overall weight increased to 1500kg, which had a knock-on effect
on performance and reduced the top speed and climb rate. As a result of this, things quickly
moved on to the A5M2, which featured the improved Kotobuki 2 Kai 3A. This gave 610 hp at take-off
and now drove a three-blade propeller. Other changes included the shortening of
the exhaust pipes, the splitting of the carburettor air intakes in two,
and the shortening of the engine mounts to maintain the centre of gravity. The maximum
speed rose to 426 km/h and the climb rate to 5000 meters was just under eight minutes.
Though the weight had again increased, which slightly affected overall manoeuvrability,
the increase in other performance metrics outweighed this drawback, and the A5M2
entered production at the end of spring 1937. The outbreak of the second Sino-Japanese war
accelerated the delivery if A5Ms to operational units, with the first arriving just four days
after the start of hostilities. They first saw combat with the 13th Koku tai – the Imperial
Japanese equivalent of an air group – above the skies of Nanjing. Despite only being available
in small numbers, the A5M enjoyed a large deal of superiority in the opening months of the conflict
as the opposing Chinese forces were mostly fielding outdated planes.
However, there were still some losses, though some of these were attributed to the Chinese
fielding of Breda 27s. Though in many ways it was the Italian love-child of the P-26 peashooter,
its general profile was still similar enough to the A5M to confuse Japan’s more inexperienced
pilots, which led to some unfortunate incidents. Following the capture of Shanghai, and as the
Japanese army moved on Nanking, the Chinese air resistance grew much fiercer. This was in part
thanks to the influx of Soviet equipment, such as the Polikarpov I-152 and I-16.
During the offensive with continued until the fall of Nanking, the A5M clashed with these fighters on
numerous occasions. At this time the A5Ms were mostly charged with escorting the G2H and G3M
bombers and so a lot of their combat was against enemy fighters scrambled to intercept them.
Initially the Soviet fighters proved to be a tough nut to crack as the A5M only had
two rifle-calibre machine guns. However, after a month or two of relatively disappointing combat,
the Japanese pilots had begun to take the measure of these new opponents
and their luck improved. Though less powerful, the A5M proved to be more manoeuvrable overall
and the strength of its airframe proved to be more robust than expected.
In one particular demonstration of this, Petty Officer Kashimura was able to bring
his plane back to base after losing a third of his port wing from an enemy ramming attack.
While the combat continued over the skies of China, work had begun on the A5M2b.
This new version reverted to the Kotobuki 3 engine, which was now behaving itself, and a
number of minor changes resulting from combat experiences in china were also introduced.
These included the provision for the fighter to carry two 30kg bobs,
a larger windscreen, tailfin, and more importantly came the addition of a fully enclosed canopy.
Unfortunately, all of this added more weight, which led to pilot complaints
about reduced performance. That being said, they were far more vocal about the canopy,
which they claimed seriously limited visibility. It was so disliked that many operational fighters
would have these canopies removed by ground crews in the field; this eventually led to
the A5M2b having its production changed back to an open-cockpit configuration.
The A5M3 was not a production model, but an experiment to test the fitting of a Hispano-Suiza
liquid cooled engine as well as a 20mm Hispano cannon. Though these trials produced some
very promising performance figures, the design was not adopted as the Imperial Japanese Navy wanted
no reliance on foreign built equipment. And so we arrive at the A5M4, which is
usually the model that this aircraft is most remembered for. This model was specifically
developed to tackle Chinese aircraft that were out of the range of the A5M2,
their bases having been moved further inland. Externally, this new version was almost identical
to the last production A5M2bs, upon which changes had been made to the landing gear, windscreen and
rear fuselage. But there were some other changes. Apart from the new engine, it also featured
attachments for a 160 litre drop tank which gave it a 648km range.
This was later further improved with the addition of an even larger 210 litre drop tank. Built in
the largest numbers, and eventually redesignated as the Model 24, it was powered by the Kotobuki 41
engine which gave 710hp at take-off. Even later the Kotobuki 41 Kai
engine was introduced, and the new variant received the designation A5M4 Model 34.
Both production variants were delivered to front line units from 1938 up until 1941. During 1939
the A5M had very few combat opportunities owing to shrinking number of Chinese combat planes.
Most of the activity was focused around assault missions and general patrol
duties around Japanese bases. There was a brief resurgence of activity in December,
when a sudden onset of Chinse bomber attacks struck the main forward Japanese airfield.
The last major air battles took place at the end of the year and the start of 1940.
The first of them involved 13 A5Ms against 20 I-16s and I-152, of which 14 were shot down for
the loss of a single A5M. During the second engagement, 26 A5Ms fought a similar force,
shooting down 13 enemy planes for the loss of two.
Combat over China produced several aces flying the A5M, and many of these would prove invaluable
for training Japanese Naval air crews in the lead up to the conflict against the United States.
When the Pacific war eventually began, the United States and Great Britain still thought the A5M
formed the bulk of Japanese Naval fighter units – and as such assigned it the code name Claude.
In fact, the only units still fielding the A5M in a non-reserve capacity were the carriers Ryujo,
Zuiho, and Hosho. This resulted in many eggs on many faces when the A6M2 – the dreaded Zero –
started appearing in large numbers and running circles around the older American fighters.
With the exception of the attack against Davao, no A5M4s participated in offensive action against
the allies, though some would see action in a defensive manner over the Marshall Islands.
The last combat sortie for the A5M took place on the 7th of May 1942, when the aircraft carrier
Shoho was attacked by US torpedo bombers. Two A5Ms and four A6Ms managed to get airborne…
before seven torpedoes and 13 bombs sent the Shoho on a one-way trip to the seabed. Though
they destroyed 3 US planes for no losses, all but one had to ditch in the sea, with the other
managing to land at a nearby island. After this the bulk of the remaining A5Ms were kept in Japan
for use by reserve and training units. This also led to the A5M4-K, which was a two
seat training model that was introduced in 1942. In total 103 of these planes were built and they
remained in service until the end of the war. Like many other older, defunct, or otherwise
obsolete aircraft, these would be used alongside the remaining A5Ms for Kamikaze attacks as the
US Navy sailed ever close to the home island. And so ended the career of the A5M, the fighter
that propelled Mitsubishi into the good graces of the Imperial Japanese Navy, and one whose
combat experience led to the development of the A6M2 Zero. It also provided the air
force with a large supply of experience pilots and instructors for the upcoming conflict with the US,
and along with the Ki-27 it led to some key changes in Japanese aerial doctrine. All of this
will be better explained in another video that I have planned, one that will take a much close
look at the air war between China and Japan. But that is a topic for another day. As always
thank you all so much for watching, and I’ll catch you all next time. Goodbye.