The P.W.S.35 Ogar (Hound) was a training aircraft loosely based on the Bucker Bu 131 Jungmann but which had only reached the prototype stage when the Germans invaded Poland in 1939.
The Jungmann made its maiden flight in 1934, and by 1935 was impressing visiting observers with its combination of good handling and aerobatic capability. General Ludomil Rayski, then a senior officer and soon to become head of the air force, remarked that a similar aircraft would be of value to the Polish Air Force, and this inspired a trio of designers – Kazimierz Nowicki, Marian Piatek and Michal Rosnowski to begin work on a similar design at Lwow. However work on the new design didn’t really make much progress until the three designers moved to P.W.S. in February 1937. Work then sped up, as the company hoped it would be the successor to the P.W.S.26, a capable trainer but based on a design from 1927.
At P.W.S. the design became the P.W.S.35. The 130hp P.Z.Inz Major inline engine was selected, and the initial design was estimated to have a top speed of 136.7mph at sea level at a weight of 1,587lb. Late in 1937 a contract was issued for two prototypes. As they were being built the design was modified several times, each adding weight, and they emerged with a loaded weigh of 1,896lb. When the first prototype made its maiden flight in the summer of 1938 its performance was lower than expected, although its handling was excellent
The P.W.S.35 was a staggered wing biplane. The fuselage had a rectangular cross section and was built with welded chrome-molybdenum tubes covered with fabric for most of its length. The engine and cockpit areas were covered with duralumin and the top decking was plywood. Both cockpits had full controls and instruments.
Visually it did end up resembling the Jungmann, not least because of the similar engine installations and flat sided fuselages. It was larger and heavier, but also had a more powerful engine, which gave it a better top speed and service ceiling.
Compared to the P.W.S.28 it was smaller and lighter, but also had 90hp less power, so was slower.
Despite the lower performance, the aircraft’s handling was impressive enough to convince P.W.S. to prepare for large scale manufacture. It is possible that work may have begun on a batch of fifty aircraft in the summer of 1939, and two may have been completed before the German invasion.
Engine: P.Z.Inz Major inline engine
Span: 26ft 3.25in
Length: 22ft 11.75in
Height: 8ft 2.75in
Loaded Weight: 1,896lb
Maximum Speed: 124.2mph at sea level
Cruising Speed: 99.4mph
Range: 404 miles