The P.W.S.5 was originally designed as a two-seat observation and liaison aircraft, but entered service in small numbers as a two-seat trainer, the first in a line of P.W.S. training aircraft.
Work on the P.W.S.5 began in response to a Polish Department of Aeronautics requirement for a two seat observation/ liaison aircraft to be powered by a Polish built 220hp Wright J.5 radial engine that was issued in 1927.
P.W.S. responded to the request with the only biplane to be submitted. This was originally given the designation P.W.S.7, before early in 1929 becoming the P.W.S.5 (as part of a wider revision of the company’s designations). The P.W.S.5 was a two-seat, unequal span biplane, with the shorter upper wing staggered slightly in front of the longer lower wing. The wings were built around two spars, with plywood covering from the leading edge to the rear spar and fabric from the rear spar to the trailing edge. On the five pre-production aircraft the top wing carried narrow-chord slotted ailerons which could also be used as landing flaps, while on the prototypes both wings carried ailerons. The fuselage was built around a rectangular wooden framework, and was covered with duralumin sheeting around the engine and plywood elsewhere. The observer’s cockpit had dual controls and basic flight instruments, and could carry a Lewis gun on a Scaff ring.
P.W.S., P.Z.L. and Lublin were all given contracts to produce two flying prototypes, an static test airframe and then five pre-production aircraft, indicating just how a priority the Polish military gave to this type.
Sturctural tests on the P.W.S. aircraft were carried out in the autumn of 1928, and the first prototype made its maiden flight on 20 December 1928. Early test flights revealed stability problems, so the second prototype was modified to have a shorter forward fuselage, and an enlarged rudder and elevators on the tail. This aircraft, with the designation P.W.S.5a, made its maiden flight in late February 1929 and had much better handling. However during its service trials it failed to achieve its estimated performance figures, and came third behind the Lublin R-X (which became the basis of the production Lublin R-XIII) and the P.Z.L. L.2 (which was also produced although in smaller numbers). P.W.S. attempted to blame the Wright two-blade wooden airscrew used during the trials, but other propellers didn’t improve its performance.
The five pre-production aircraft were still built, but as operational trainers. They were given the P.W.S. designation P.W.S.5t2 (trainer, two seat). These aircraft were armed with a single Lewis gun on a Scarff ring in the observers cockpit, and had message pick-up gear. The first was completed in the summer of 1929 and by the end of the year all five had been delivered. At first they were issued individually to different operational units, but later most were moved to training units, where they remained in use into the late 1930s.
During 1927 work began on an improved version of the aircraft, the P.W.S.6, which used Handley page leading edge slots. This was a generally successful design, but by the time the single prototype had been completed the Lublin R-XIII had already been ordered, so only the prototype was built.
Engine: Polish Skoda Works Wright J.5 Whirlwind nine-cylinder radial air cooled engine
Span: 29ft 6.75in
Length: 22ft 3.25in
Height: 9ft 6.25in
Empty Weight: 1,735lb
Normal Loaded Weight: 2,601lb
Maximum Speed: 96.3mph at sea level, 92.5mph at 3,280ft
Climb rate: 8min 36sec to 3,280ft, 39min 19sec to 9,842ft
Guns: One Lewis gun on flexible mount