First flight of Kaman's first helicopter (Kaman K-125A)
Wednesday, January 15, 1947
This was a twin rotor sychropter. The following reference provides a detailed account of the event,
"Kaman Aerospace Corporation: Evolution of the Helicopter", R.H. Jones, VERTIFLITE May/June 1984, Page 25
In other references this aircraft is referred to by the designation K-125.
Source: AHS Calendar January 2009