Question: What was the first successful aircraft designed by the aviation pioneer who built the Sikorsky S-6?
Sentence (from "Igor Sikorsky"): Igor Ivanovich Sikorsky (Russian: И́горь Ива́нович Сико́рский ; ] , "Ígor' Ivánovič Sikórskij"; , "Ihor Ivanovych Sikorskyi"; May 25, 1889 – October 26, 1972), was a Russian-American aviation pioneer in both helicopters and fixed-wing aircraft.
Relevant evidence: Yes