Production of the KhAl-5, designated R-10, was launched at the Kharkov and Saratov factories. The R-10 was a two-seat low wing monoplane of all-wooden construction except for its empennage and ailerons. It was intended for reconnaissance missions, and also could be used as an attack aircraft and short-range bomber. Its fuselage was a semimonocoque structure of which the wing centre section and fin formed an integral part. From the fourth aircraft the fabric covered rudder and ailerons had Duralumin frames, and from the fourteenth production aircraft the tailplane was Duralumin. Pneumatically operated Shrenk-type flaps reduced the landing run significantly. The landing gear comprised a retractable main undercarriage with braked wheels and a castoring tailwheel.
Initially the R-10 had an M-25A engine, but later the 730hp (544kW) M-25V was installed. From the tenth production aircraft the VISh-6 two-bladed metal propeller was fitted. Fuel was contained in 79 gallon (360 litre) wing tanks. The first 24 aircraft had riveted fuel tanks, but welded and protected tanks were then adopted.
The R-10’s standard armament consisted of three ShKAS machine guns; two in the wing and one turret mounted. The bomb bay had cassette-type bomb carriers able to carry 22,55 and 110lb (10, 25 and 50kg) bombs up to a total weight of 660lb (300kg). Sighting and bomb-dropping was performed by the pilot/ observer using an OPB-1 Mor PAK-1 sight.
During series production the R-10 was constantly improved. The KhAl-5bis prototype reengined with an M-25E reached 264mph (425 km/h) during NII WS flight tests in 1938. Modified and strengthened production R-10s were powered by the more powerful M-88, M-62 and M-63s, and a trainer version was designed. Some of the aircraft phased out of the air force inventory and given the civil designation PS-5 were used by state airline Aeroflot.
More than 490 R-10s were manufactured. The pilots of the 43rd Air Brigade, commanded by HSU Nikolay Kamanin, were the first to familiarise themselves with the aircraft. The pilots liked the new aircraft, which was easy to fly. The R-10’s Service history includes combats over Khalkhin-Gol in the summer of 1939. Partly disassembled aircraft were delivered to their units by railway, and were received in the desert region of Tamtsak-Bulak by brigades of plant assemblers who quickly prepared them for flight.
A few regiments equipped with the R-10 participated in the Finnish War of 1939. Soviet pilots flying there had to endure extremely severe conditions, flying reconnaissance and attack missions over the Mannergaim Line in low cloud, in temperatures down to -50* of frost, and in snow storms and Arctic winds.
In late 1940 the aged R-10s began to be replaced by more up to date aircraft. Nevertheless, at the beginning of the Second World War the they played an active part in the battles of Moscow and Leningrad, flying reconnaissance missions alongside Sukhoi Su-2s and YakovlevYak-4s, and were used for close air support. A few remaining R-10s were still operational in 1943.
