During the interwar period, Italian manufacturer Fiat produced a legendary line of Biplane
fighters. These, among a few other designs around the world, represented the zenith of
the biplane as a fighting machine, but unlike many other countries, Italy would continue to
operate its biplanes for a considerable time. Clear evidence of this was the Fiat Cr.42 Falco,
which did not enter service until 1939. The Cr.42 and its predecessor the Cr.32 are by far
the most iconic of the Fiat Biplanes, but before we look at those its important to understand what
came before. By the time the Cr.32 entered service in 1933, Fiat had already produced several other
biplane designs, and the two most important of these early models were the Cr.1, the Cr.20.
In the early 1920s the majority of military aircraft around the world had been developed
and built during the First World War. There was a huge surplus following the armistice, and many
nations were happy to use their existing stock for a considerable time. It made sense, most of
the public had no taste for further war after the horrors they had just witnessed, and much of the
world was now focused on turning the aircraft back into a civil machine rather than a war machine.
That being said, there was still development being made in the field of military aviation,
albeit at a more conservative pace. One of the exceptions was Italy, a country that
had been at the forefront of aerial warfare since before the first world war. The newly
formed Regia Aeronautica was keen to maintain a strong lead in this field, and so in 1923 they
began a project to develop a brand-new fighter. For this Fiat and SIAI (which would soon become
Savoia-Marchetti) were approached to submit competing designs, and it was Fiat that would
triumph. One of their engineers, Cellestino Rosatelli quickly produced two prototypes,
known as MM.1 and MM.2. They were physically similar, except that they both had different
variant of the Hispano-Suiza V8 engine, and one had a counterbalanced rudder.
Built as a sesquiplane, Rosatelli’s design was uncommon because the lower wing had a greater span
than the upper, which made it look like somebody had stuck the wings on upside down. Additionally,
the wings were connected by a warren-style inverted “W” strut, which again was a fairly
uncommon arrangement. Though it looked odd, it at least provide a great deal of strength. But aside
from this, it was built mostly to the standards of the time. Its framework was built of wood,
which was covered in fabric; it had a fixed axle undercarriage and a tailskid; it featured an open
cockpit; and it had two synchronised 7.7mm machine guns that fired through the propeller arc.
Both prototypes appear to have flown in late 1923, though exact dates are unknown,
then in the following months they competed against the design submitted by SIAI,
outperforming it by a considerable margin. Upon completion of evaluations, the Regia Aeronautica
was supremely happy with Fiat’s design and it was ordered into production as the CR.1.
The C standing for Caccia (or fighter/hunter) and R standing for Rosatelli, the designer.
In 1925 the first two production models were used for service evaluations, where they outpaced the
French Nieuport-Delage 29, clocking in a top speed of 272 km.h. That same year the first production
models reached Italian air units, with the total production run of the Cr.1 amounting
to approximately 240 to 250 units. Due to the timing of its development,
the Cr.1 would never see combat, but they did provide the Regia Aeronautica with a
solid platform on which to train their pilots. Throughout the 1920s the Cr.1 was well-liked by
its pilots, who praised its easy handling and forgiving nature, and its success won
Rosatelli an excellent reputation, both within Fiat and with the Regia Aeronautica itself.
During its quiet but successful service life, a few attempts were made to improve the Cr.1 to
keep up with other designs that were emerging in the late 1920s. The prototype CR.2 was
actually less powerful than the Cr.1, but it featured an air-cooled Armstrong Siddely Lynx;
the Cr.5 was far more powerful, boasting the licence-built Alfa Romeo Jupiter of 650hp; and the
Cr.10 featured Fiat’s own engine: the 410hp A.20. But by 1926, Fiat was already moving on to the
Cr.20, so any attempts to improve the longevity of the Cr.1 were modest at best. Still,
the Cr.1 was successful enough that it secured an overseas order from Latvia. Poland and Belgium
had also expressed interest, but no orders for them eventuated. Nine Cr.1s were ordered for
the Latvian navy in 1926 and all of them had been delivered by 1927. Equipped with 300hp
Hispano-Suiza engines, they remained in Latvian service until late 1936, being withdrawn from
service just a few months before the last of the Italian Cr.1s were also retired.
All in all, Fiat’s first outing with their biplane fighter had been very successful. But
it was clear that the old-school construction of the Cr.1 would limit its service life,
and so Rosatelli quickly got to work on a modernised replacement: the Cr.20.
This design saw two major changes from the old Cr.1. Firstly, the wing configuration was flipped,
with the upper wing now having the greater span, like on most traditional biplanes;
and secondly, it featured all-metal structure. Once again two prototypes were constructed,
though its uncertain as to what the differences between them were (information on this particular
aircraft is pretty thin on the ground), though there seem to be suggestions that each had a
slightly different version of the 12-cylinder Fiat A.20. In an age where armour protection for
the pilot had yet to come about, the armament remained the same. The Cr.20 inherited the
twin 7.7mm machine guns of the Cr.1, which once again fired through the propeller arc,
though there seems to be evidence that it carried more ammunition.
The prototypes completed their first flights in June 1926, and like their predecessor the
performance immediately impressed the officers of the Regia Aeronautica. Fiat’s test pilot was so
confident they put the prototype through loops, rolls, immelmanns and steep dives within just a
few hours of flight time. The aircraft was almost immediately ordered into production as the Cr.20,
and this time it would see service in a number of different variants.
Approximately 250 of the original Cr.20 design would eventually be produced. Though the top
speed was almost identical to the Cr.1, the physical endurance of the airframe was
superior thanks to its all-metal construction, and it was able to absorb the rough impacts on
ruidimentary airstrips with greater ease. This was particularly useful during this time as the Regia
Aeronautica was rapidly expanding, and a large number of pilots were relatively inexperienced.
To this end, a training version of the Cr.20 was developed, known as the Cr.20B. This was also used
as a liaison aircraft, but the exact details of its widespread use throughout the Regia
Aeronautica are sketchy at best, and from what I could find it was built only in small numbers,
with a production run of less than 50. Another model that was built in limited numbers
was the Cr.20 “Idro”. This was a floatplane version that entered service at some point
in the late 1920s. Though it was still a Fiat design, it appears that all 46 of these were built
by Macchi. Additionally, it seems that the floats used in the design were either the precursor for,
or perhaps the results of, the 1929 Fiat C.29 - which was submitted as an entrant to the Schneider
Cup, though it would never race. In contrast to the original Cr.20, which handled beautifully,
the Idro’s handling was once described as vicious. This was mostly because it developed a nasty
tendency to stall suddenly and violently when put through certain manoeuvres, and it soon became
known that putting an Idro through an inverted loop was like playing Russian roulette with a
fully loaded revolver: highly unadvisable. After the original batch of 250 Cr.20s were
completed, things then moved onto the Cr.20Bis. This was a modernised version of the design
that featured some minor improvements. The most noticeable was the change to the undercarriage;
the fixed axle was deleted, and individual oleo-suspension was installed. The bis also
had a slightly reduced wing area, and some minor adjustments to the internal structure, mostly to
do with reinforcements to the steel framework. This traded a reduction in top speed for better
handling and strength, as according to the pilot’s manual, the Cr.20 had a ground level top speed of
270 km hr, and the bis could only manage 250. Attempts to improve this were made with two
further variants: the Cr.20bis A.Q, and the Cr.20 ASSO. The Cr.20 A.Q was identical to
the bis variant, but it was now powered by a 425hp Fiat A.25 A.Q – the AQ standing for ‘Alta Quota’
or high output. The Cr.20 ASSO was similarly powered by the 450hp Isotta-Fraschini Asso.
But in spite of the increased power of both engines, they came at the cost of increased
weight and reduced range, and, ultimately no real improvement in top speed either.
But, despite these final disappointments, the Cr.20 was a well built, well handled,
and highly popular fighter. Its popularity partly came from its good handling characteristics,
but also partly from the remarkably advanced equipment that the Cr.20 came with.
To improve the effectiveness of training, the Cr.20s came with a gun-camera that was capable of
recording up to 1000 frames per second. Because of this, It came with thirty meters of film,
and the system was set into motion by a spring connected to the gun system. Once the film had
been used up, a small buzzer would sound to alert the pilot that filming had ceased, after
which they would land to review their gunnery. Along with this fairly advanced piece of kit,
the Cr.20 also came with a complete electric system, which was charged by
a 12-volt Marelli dynamo. The system had two batteries, one that powered the main system,
and a secondary one that powered the take-off and navigation lights on a separate circuit.
Other equipment installed showed that pilot safety and comfort were placed high on the
priority list when designing the Cr.20; something that wasn’t always the case with
aircraft design of the 1920s. The first example was a fully automatic oxygen supply system,
which was activated once the aircraft’s altitude exceeded 3,000 meters, and the second was a
built in suppression system for engine fires. A loud horn would blare if a fire was detected,
though in an open-cockpit aircraft with the engine directly in front of you I can’t imagine a pilot
not detecting the fire…but you never know, and the system was activated by the press of a button.
Unfortunately for the pilot this system used carbon tetrachloride for the supressing agent,
which for those of you unaware is a nasty chemical which, when exposed to in high concentrations
(such as in a fire supressing scenario in an open cockpit aircraft) can affect the central nervous
system, lead to degeneration of the liver and kidneys, and -with prolonged exposure- death.
Admittedly this was not common knowledge at the time, and so this system was received
favourably by the pilots who would use it. Because of its good handling, relatively high
top speed, modern equipment, and semi-helpful / semi-harmful fire suppression system,
the Cr.20 not only saw extensive use in Italy (with 32 Squadrons operating them by 1933),
but also overseas as well. The Cr.20 saw use with the Air Forces of Austria, Hungary,
Lithuania, Poland, Paraguay, and Spain, and, unlike the Cr.1, it would also see combat.
With Italy, it saw a brief spate of action during the Second Italo-Ethiopian war. In this theatre it
did not see use as a dedicated fighter, due to a lack of opposing air power, but as a rudimentary
close-air-support weapon, mostly striking soft targets such as encampments and supply dumps.
This of course was limited to gun runs as the Cr.20 did not have provision to carry bombs.
With Paraguay, the five Cr.20s sold to them would be the only fighter aircraft
fielded against the Bolivians during the Chaco War. The Aerial component