Quoted from "The complete book of fighters" by William Green and Gordon Swanborough.
"In 1938, A V Sylvansky, assisted by Yu B Sturtsel and V D Yarovitsky, established an OKB with the express purpose of designing and building a single seat frontal fighter to a requirement formulated by the UV-VS. Referred to as the IS (Istrebitel Silvansky), the fighter was a low wing cantilever monoplane of mixed construction powered by a turmansky M-88 14-cylinder two row radial engine with a two speed supercharger and rated at 1100hp. Owing to a "miscalculation", the inward retracting mainwheel legs were of longer stroke than could be accommodated by the bays into which they were intended to retract. Once shortened, the legs provided insufficient ground clearance for the propeller, and as a temporary expedient and in order not to delay flight testing, this was allegedly cropped by four inches (10cm). The prototype SI was transferred to the LII at moscow in the summer of 1939. There it was found that, with it's cropped propeller, the aircraft required and inordinately long take-off run. Nonetheless, one attempt was apparently made to fly the aircraft, the test pilot succeeding in attaining an altitude of some 1000 feet (300m) at which the aircraft proved virtually unmanageable. He managed to effect a landing, pronounced the IS was unflyable, and the prototype was scrapped, Silvansky's team being dispersed. No data relating to the IS seem to have survived"
