This is a Significant Technology milestone.
The aircraft, a modified Cierva C.7, was piloted by Reginald Truelove. The articulation was installed to reduce the in-plane loads that had lead to an earlier crash of a Cierva C.6C when 2 blades became detached in flight. This would prove to be one the fundamental developments to the successful development of practical rotorcraft.
(Source: From the Cierva C.4 to the CarterCopter: An Anlaysis of How the Autogiro Became the Gyroplane, Bruce H. Charnov, Hofstra University, Paper presented at the AHS 60th Annual Forum, Baltimore, MD, June 7-10, 2004)