The strength of the R.W.D. design team was undoubtedly in aircraft of monoplane high-wing layout: an attempt to develop a twin-engine six-passenger feeder-liner of low-wing monoplane configuration, the R.W.D.11, failed to progress beyond the prototype stage. The following R.W.D.13 was, in effect, a lower-powered three-seat development of the R.W.D.6, of which two examples had taken part in the Challenge de Tourisme International of 1932. A braced high-wing monoplane of composite construction, with a wing that was foldable and incorporated wide-span leading-edge slats, the three-seat R.W.D.13 was otherwise conventional and powered in prototype form by an engine of 97kW. An initial order for 10 aircraft was followed by a series of repeat orders, and when production ended in September 1939 a total of about 100 had been built. The total included 15 R.W.D.13S ambulances, equipped for a pilot, stretcher case and medical attendant. Some 20 were exported, one of them being given to the Shah of Iran as a wedding present from the Polish government, and four were used as liaison aircraft by the Nationalist forces in the Spanish Civil War. Both the R.W.D.13 tourer and R.W.D.13S ambulance were built under licence in Yugoslavia, seeing extensive service for both civil and military use.
With the outbreak of World War II in September 1939 a number of R.W.D.13s were impressed for service with the Polish air force, and before the country fell to the German forces about 40 were flown to Romania, where most were used by that country's air force throughout the war; when peace was restored some were returned to Poland.