Lublin R-X

The Lublin R-X was a Polish liaison aircraft, built in 1929 in the Plage i Laśkiewicz factory in Lublin.

Development
In 1927, the Polish War Ministry opened a contest for a military liaison and observation plane. It was meant to operate from casual airfields, used by Army land units. The private factory Plage i Laśkiewicz in Lublin proposed the Lublin R-X, designed in 1928 by Jerzy Rudlicki. The first prototype was flown on February 1, 1929. Although its mass was bigger, and the performance was lower, than expected, the plane appeared quite successful and five pre-series aircraft were built in 1929, designated R-Xa. The R-Xa were fitted with an armament - a machine gun in a rear cab.

After evaluation by the Polish Air Force, the R-Xa won the contest for a liaison plane in December 1929, over PWS-5t2 and PZL Ł.2, having the shortest take-off and landing, good handling at low speed and satisfactory performance, but the factory was ordered to develop design further. The result was a new design Lublin R-XIII, basing upon the R-X construction and mass-produced.

The seventh R-X was built in 1929 as a long-distance sports plane. It had fuel tanks 800 l and a range of 2500 km. In 1932 it was modified with an addition of the Townend ring onto the engine, wheels' covers and metal propeller, and designated the R-Xa bis. The R-Xs had factory numbers 52-1 to 52-7.

Design
Mixed construction (steel and wood) braced high-wing (parasol) monoplane, conventional in layout. A fuselage of a steel frame, canvas-covered (engine part was duralumin-covered). Rectangular wings with elliptical ends, two-spar, of wooden construction, canvas and plywood covered. Wings could be dismounted. Crew of two, sitting in tandem in open cockpits, with twin controls. Conventional fixed landing gear, with a rear skid. The observer had a 7.7 mm machine gun on a ring mounting. A 9 cylinder air-cooled radial engine Wright Whirlwind J-5Ab (produced in Poland by Polish Skoda Works) with 162 kW (220 hp) nominal power and 176 kW (240 hp) take-off power. Two-blade wooden or metal propeller, 2.7 m diameter. Fuel tank 250 liters in the fuselage, could be dropped in case of fire emergency (normal fuel capacity was 200 l).

Operational service
The pre-series R-Xa were used by the Polish Air Force since 1929. In 1931 three aircraft were modified as liaison staff machines, by removing a machine gun ring from a rear cab and fitting it with a comfortable seat.

The R-Xa bis was used for several long-distance flights. It carried a registration SP-ABW and was named "Srebrny Ptak" (Silver Bird). On August 25, 1929 it flew from Poznań to Barcelona (1800 km non stop). In September 23 - October 7, 1931 Stanisław Karpiński flew it around the Europe (6450 km Warsaw - Bucharest - Stambul - Rome - Torino - London - Warsaw).

In October 2 - October 24, 1932 Stanisław Karpiński flew the R-Xa bis from Warsaw through Stambul, Bagdad, Teheran, Kabul, Cairo to Warsaw (14,390 km in 108 h 50 min). The plane was scrapped in 1935.

Operators

 * Polish Air Force
 * Polish Air Force