Question: The Sikorsky R-4 was a two-seat helicopter designed by a man that won the highest awardat the 1912 Moscow Aviation Exhibition for what airplane? 

Related documents: [0]  [DOC] The Sikorsky R-4 was a two-seat helicopter designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter used by the United States Army Air Forces, the United States Navy, the United States Coast Guard and the United Kingdom's Royal Air Force and Royal Navy. In U.S. Navy and U.S. Coast Guard service, the helicopter was known as the Sikorsky HNS-1. In British service, it was known as the Hoverfly. [END] 
[1]  [DOC] 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. First success came with the S-2, the second aircraft of his design and construction. His fifth airplane, the S-5, won him national recognition as well as F.A.I. license Number 64. His S-6-A received the highest award at the 1912 Moscow Aviation Exhibition. and in the fall of that year the aircraft won for its young designer, builder and pilot first prize in the military competition at Petrograd. [END]  
Answer: S-6-A
S-6-A