After the IAR's efforts finally paid off once they received
the order for the IAR-14, Elie Carafoli was ready once again to start
working on new fighter design. The result was the IAR-15 fighter, undoutably
the finest of all his creations and the one aircraft of its pre-IAR
80 creations that could take on anything the world could throw at him.
Like all previous designs, the new airframe was also built
from a combination of wood and metal and covered with duralumin sheets
and pine plywood. This time the fuselage was also to suffer major changes
together with the tail, wings, undercarriage and the engine. The cross
section of the forward fuselage became round with a long-chord engine
cowling, whilst the rear fuselage was enlarged in diameter and reinforced.
A NACA type ring was mounted in the nose, covering the engine. The tail's
shape and profile were modified from a round one to a triangular one.
For the first time, the undercarriage was changed, becoming aerodynamically
cleaner, since it consisted of a single strut with wheel spats mounted
near the wing roots and, also for the first time, the tail "ski" was replaced by a small wheel.
Wings were shortened to just 11 meters and the wingtips were
rounded furthermore to improve airspeed and maneuverability. It was
suggested to fit the plane again with the infamous "anti-crash" pylon, but because of its notorious bad influence a rounded knob was
mounted behind the pilot's head rest instead.
Several of the powerplants previously used were suggested,
but the end Carafoli chose to abandon the classical in-line engines
since they were either too heavy or simply not powerful enough for a
fighter. Instead, a Gnome-Rhone 9Krse, nine-cylinder, radial engine
rated at 600 HP at 4000 meters , was fitted to the prototype with very
good results. As armament, the aircraft retained the standard pair of
two synchronized Vickers 7.7 mm machine guns firing through the propeller
common for all early IAR fighter projects. Each machine gun had a good
500 rounds supply of ammunition.
The aircraft made its first flights in early 1934 and right from the beginning it demonstrated its outstanding qualities. With a top speed of 375 km/h in level flight, the IAR-15 was very fast for its time and climbing speed was excellent as well, with just 8 minutes needed to reach a 5000 meters altitude.
Maneuverability was also good, although
it wasn't yet equal to that of the nimble PZL P-11. The IAR-15 was, without
doubt, capable of intercepting any bomber of the day ; furthermore, test
pilots and engineers alike stated that their fighter had shown itself
to be more than a match for any other monoplane or biplane fighter in
service at that time.Unfortunately, the ARR leaders, although they appreciated the
aircraft's capabilities, didn't believe that their fighter squadrons needed
it. With the PZL P-11 in service for less than a year, it was believed
that it would be too difficult and too expensive to have two different
types of fighters in service at the same time. Only five ( or six ) IAR-15
were ordered instead of the large orders that the IAR had expected. They
were manufactured between 1934-1935, with only a couple of modifications
: a three-blade metal propeller replaced the original two-blade wooden
airscrew, and additional instruments were fitted on the instrument panel.