An early photo of the JOV-3 helicopter, with NX registration and early landing gear. Airframe built in 1947 according to the FAA and first flown before March 1948. Photo almost certainly taken at the small Boulevard Airport near Philadelphia. Photo from: Wright State University

A better view of the JOV-3, perhaps flying over the Delaware River near Boulevard Airport, Pennsylvania where the Helicopter Engineering Research Corporation was based. Photo from: Vertical Flight Society

The Helicopter Engineering Research Corporation (HERC) of Pennsylvania was formed by former Piasecki engineers Drago Jovanovich and Frank Kozloski to build the JOV-3 two-seater. It was the predecessor of the McCulloch MC-4, later turned into the Jovair 4. Early helicopter advertising photographs are fascinating stuff. This one is rather odd, as it looks like the pilot is being flagged down to be breathalyzed! Photo from: Vertical Flight Society