Here is an interesting way to look at trial and error. . .
“At that time (1909) the chief engineer was almost always the chief test pilot as well. That had the fortunate result of eliminating poor engineering early in aviation”.
The helicopter shown is a 1981 Sikorsky S-76A probably operating as University MedEvac 2, in Philadelphia, PA. FlightAware indicates the the aircraft is now probably retired after spending some time in Cleveland. University MedEvac , one of the pioneering programs in the country, are now flying several Eurocopter (Airbus) models.