Up until the mid 50s', young Swiss military pilots learnt the basic skills on the Bücker Jungman and Jungmeister to then move on to the Pilatus P2 for instrument and formation flying and, in a following phase, moved on to the North American AT-16 and Morane D3801 for tactical flying.
The basic idea was thus to build an aircraft that could cover all training's areas and could prepare the young pilots to transition to the De Havilland Vampire and Venom jet fighters.
A tricicle gear, superb visibility, an IFR panel and, last but not least, a competitive price were deemed to be essential.
It was clear from the beginning, that there would be no financial backing from the government. The whole burden would have to be borne by Pilatus. A man named Heinrich Fierz would make it happen
At some stage, Landolf suggested to shorten the fuselage by 50cm to increase manoeuverability and save on weight, without influencing stability. Fierz accepted Landolf's proposal, ignoring, at that stage, that this would lead to serious problems later on.
The maiden flight of P3-01 HB-HON prototype, powered by a Lycoming GO-435-C2 and a 2 blades Hartzell constant speed propeller, was made with Georg Gisler at the controls. Gisler confirmed the validity of Landolf's work in almost all areas. HB-HON was extensively tested by the Swiss Air Force during 1953 and 1954.
A second prototype, P3-02 HB-HOO took the air in August 1954, powered by a different engine, the Lycoming GO-435-C2-A2 with a dry sump oil system, that was more suitable for aerobatics and was equipped for military purposes. It also had hardpoints under the wings to carry light weaponry and machine guns for gunnery training. An option that was carried over to the -03 series.
HB-HOO was used in the legendary demonstration flight, that took place in Altenrhein.
Fierz, born in Herrliberg in 1897, after completing his studies at Winterthur's technical college, moved to the USA, where he lived for 5 years, working for Douglas, Curtiss and Packard.
Upon his return to Switzerland he first worked as a Chief Engineer for the Swiss aircraft manufacturer Alfred Comte (1925 - 1933), then moved to Swissair, where he acted as Technical Director from 1934 till 1940 and finally moved to Pilatus Flugzeugwerke, where he was promoted Technical Director in 1946.
During various discussions with several KTA's high ranking officers (Kriegstechnische Abteilung), he managed to determine what Swiss Air Force's future needs were.
Fierz lead his team with competence. His decisions were largely based on his experience and on facts.
Leo Stofer was in charge of designing the fuselage, which is a semi-monocoque construction with oval section. Münch was responsible for the statics, whilst Wenzel Landolf was in charge of aerodynamics.
Their work resulted in the excellent manoeuverability and overall quality of the aircraft
Not everything was good though. The P3's most striking problem was its lack of power. It had brilliant aerodynamic characteristics, that allowed a wide range of aerobatic manoeuvers. The penalty was, however, a massive loss of altitude, that had to be regained after each short sequence. In addition, the poor climbing performance was in strong contrast with the philosophy of the time of making maximum utilisation of the vertical component in aerial combat.
Despite the modest performance, the Swiss Air Force ordered 12 aircraft, that underwent a series of tests aimed at verifying the model's viability in the training role. These were P3-03 equipped with a 3-blade Hartzell constant speed propeller.
At the same time, Pilatus was looking for further potential clients. Demonstration flights were carried outin various countries, however, despite some initial interest, there would be no orders.
Pilatus director, Mr. Alioth, ordered the construction of 6 moreairframes, the -04 series, equipped with civilian instruments (the military used the metric system). Swissair tested one of these aircraftto evaluate a possible utilisation within the SLS (Schweizerische Luftverkehrsschule), but never placed an order.
These aircraft, named the "hangar queens" were eventually sold to theBrasilian Navy. This would be Pilatus' first foreign order. Others would follow, but only many years later.
In the meantime, the Air Force found the P3 to be acceptable and ordered an additional 60 airframes, which were serialled -05 and nolonger had the underwing hardpoints for light weaponry, as well as a slightly modified electrical system. Their interest was, however,subject to a more powerful engine being installed.
Fierz studied the possibility of installing the 340PS Lycoming GSIO-480already used in the Pilatus Porter. To accomodate this engine, the front section would have had to be enlarged and stretched, causing aforward shift of the center of gravity, which would have had a negative impact on the aircraft's excellent flying characteristics. In addition,a large portion of the extra power would have been lost to the increased weight caused by the strengthened structure that would havebeen necessary. All this lead Fierz to fight against this idea and eventually convinced the Air Force to buy the standard version.