The RWD 8 was a parasol wing monoplane that was used both as a military trainer and by civilian flying clubs and was produced in larger numbers than any other Polish aircraft of the interwar period.
The RWD 8 was the last aircraft to be designed by the team of Rogalski, Wigura and Drzewiecki, who had given their initials to many of the D.W.L. company’s aircraft. In September 1932 Wigura was killed when the RWD 6 competition tourer crashed soon after it had won the IIIrd Challenge de Tourisme International in Berlin.
Work on the RWD 8 began in the autumn of 1931. It was designed from the start to meet two requirements – one from the Liga Obrony Powietrznej I Przeciwgazowej (L.O.P.P. or League of Air and Anti-gas Defence) for a cheap tourer/ training aircraft for civil flying clubs and one for a primary trainer for the Polish aircraft. It was loosely based on the Sido S.1 lightplane, which had been developed by Josef Sido, a student at the Krakow Mining Academy in 1929. This was a parasol wing monoplane which was considered for use as a military primary trainer, but rejected at least in part because no aircraft company was backing it. A handful of aircraft were built and took part in many Polish aviation contests and meetings.
The RWD 8 was also a parasol wing monoplane, with V struts supporting the wings. On the prototype and early production aircraft the outer panels of the wings tapered in thickness towards the ends, although on all but the first prototype this was soon replaced by a panel with a constant thickness.
At the start of 1932 L.O.P.P. ordered two prototypes and five production machines, soon adding a second batch of ten production aircraft. The first prototype was built with a 105-115hp Cirrus Hermes II inline engine and made its maiden flight late in 1932. The second prototype used a Walter Junior inverted inline engine and made its maiden flight early in the following year. The type soon passed its trials and was approved as a touring and training aircraft.
The first production aircraft, powered by a de Havilland Gipsy III engine, made its maiden flight in the spring of 1933. Deliveries began in the summer of 1933, with two aircraft from the first batch going to the Lwow Aeroclub. The last aircraft in the second batch of ten was the only RWD 8 to be powered by a radial engine, getting a 120hp Polish Skoda Works G.594. The RWD 8 performed well in flying contests. A third batch of 20 aircraft was produced in 1934 and 20-30 aircraft in 1935-37. About 100 civil RWD 8s were built by D.W.L., mainly powered by one of the 110hp Walter Junior, 120hp Walter Major or 120hp de Havilland Gipsy Major. Another 150 civil RWD 8s were built under license by P.W.S. The RWD 8 dominated civil flying contests in Poland in the late 1930s.
The RWD 8 also attracted the attention of the Polish military. In 1933 it defeated the P.Z.L.5bis in a contest to decide which aircraft was to replace the existing Bartel M.4 and Hanriot primary trainers. However the production contract went to P.W.S., which by that point was owned by the Polish government, after going bankrupt in 1932. The first P.W.S. built aircraft, powered by a 110hp Walter Junior, flew in mid-1934.
The military version differed in several ways from the civil version. The cockpit cut-outs were deeper, and the plywood decking between the two seats could be removed to allow the tutor to get a better view of his student. The airspeed indicator and rev counter were placed outside the cockpit in a position where they could be seen by both crew members. The undercarriage legs had P.Z.L. oleo-pneumatic shock-absorbers, and lacked the fairings used on the civil aircraft. Some later military aircraft carried an extra 5.5 gallon fuel tank while others were modified for blind flying training. The P.Z.L. undercarriage caused some problems in early aircraft, failing rough landing trials , but deliveries began in the autumn of 1934.
The military RWD 8 was built in large numbers between 1934 and 1938, peaking at almost 30 aircraft per month. Over 350 were ordered by the Polish Air Force and in November 1938 there were 349 on strength, with 245 at the military schools and 104 in reserve. Between the civil and military versions over 600 RWD 8s were eventually built.
In 1939 a significant number of RWD 8s were used as liaison aircraft. In the build-up to war thirty-six aircraft were formed into twelve flights of three and attached to combat units. Another sixty military trainers joined them during mobilization, while in September a number of civil examples were pressed into service. The RWD 8’s main role was to carry messages between the increasingly isolated army groups and Warsaw, a dangerous task that often saw them fired on by the troops of both sides. The RWD 8 was also used to harass the Germans, and on 4 October one became the last Polish aircraft to attack the Germans, dropping grenades.
Towards the end of the campaign at least 60 aircraft escaped to Romania, where they were taken over by the Romania military and pressed into service as a training aircraft. The Germans also captured several and used them at their training schools.
Engine: Walter Junior
Span: 36ft 1in
Length: 26ft 3in
Height: 7ft 6.75in
Empty Weight: 1,058-1,102lb
Normal loaded weight: 1,653lb
Maximum Speed: 108.7-114.9mph at sea level
Cruising Speed: 90.1-96.3mph
Climb rate: 4min to 3,280ft
Range: 270-310 miles