Vasilii Andrianovich Slesarev began building and altering aircraft 1913, producing modified versions of Nieuport IV and Farman XVI, before designing Svyatogor giant biplane, with 2 front wheels and 2 6 ft main wheels. Slesarev wanted 2 x 300-hp Mercedes engines to go in central engine room, driving pusher propellers by shafts and gears, but had to settle for 220-hp Renault. Construction began November 1914, and taxi tests began just 2 years later, but Svyatogor never got off ground.