After working on the design of the helicopters (H-1 and H-2) Igor Sikorsky (1889 - 1972) he started designing aircraft, Starting with the S-1 in 1910. Late in April 1911, he completed the 5th design from his hand, the S-5.
The S-5 made its first real flight on this day in aviation history. After some short (~25 seconds) straight-line flights the first circuit was flown during a four ( 4!) minute test flight on this day in aviation history.
It was powered by a 50 horsepower water-cooled engine. After "betaing" Imperial Russian Army aircraft during fly-offs watched by Czar Nicholas II in September of that year, Igor Sikorsky made some money from exhibition flights at a country fair. After some 9 - 10 hours of flight time, the aircraft was lost when it crashed during a flight when the engine stopped due to fuel starvation, while the tank was not empty.
What caused the fuel starvation, a mosquito in the fuel jet of the carburator! It just shows that we don't have fuel filters for fun these days!