courtesy of Ebay.de seller Marco (koelsch333), these images appear to depict an enclosed passenger cabin variant of the Polikarpov R-5 (ARK-5), note too the underwing containers or Kassetta. These images are taken from the album of a veteran of the (German) 254th ID, see the link below if contemplating a bid.
The R-5 was a 1930's Soviet biplane in the Wapiti mould, an unequal-span two-seater constructed largely of wood with fabric covering. The R-5 reconnaissance light bomber first flew in prototype form in 1928. Pilot and observer/gunner were seated close together in tandem open cockpits - the pilot beneath a cutout in the upper wing trailing-edge. The type saw action in Mongolia against the Japanese, fought with the Republicans in the Spanish civil war and against the Finns during the Winter war. Service continued well into WWII where it was employed as a night time nuisance raider. Click on the images to view large.
The BMW VIb in-line engine of the prototype was replaced by the 507kW Soviet-built M-17B in production aircraft. The R-5 could operate on skis or twin-floats (the latter designated R-5A or MR-5), as well as on the more normal axle-type fixed undercarriage. Standard armament was a fixed 7.62mm PV-1 machine-gun and a DA-1 weapon of the same calibre operated by the observer. Up to 250kg of bombs could be carried on underwing racks.
Many variants of the R-5 were used in the Soviet Union. These included the single-seat R-5T torpedo bomber; the heavily armed R-5Sh ground-attack aircraft; and the SSS of 1934 with 533kW M-17F engine, spatted landing gear and new ShKAS machine-guns. Civil versions were the P-5 and P-5A, the latter with cabin accommodation for four passengers, and an enclosed pilot's cockpit.
Some 7,000 of all versions of the R-5 were built. Military operations included the Spanish Civil War (31 R-5s serving with the Republicans), the campaigns in 1938-39 against the Japanese in the Far East, the 'Winter War' against Finland, and the fighting against Germany from 1941. At the time of the German invasion most R-5s had been relegated to training and liaison duties, but several hundred returned to first-line duties to equip light night-bombing 'nuisance raid' units alongside the ubiquitous Polikarpov U-2.