Prop-Fan propulsion systems have progressed from concepts and models to large scale aircraft/propulsion system integration tests. During the Prop-Fan Test Assessment program a nine foot diameter Prop-Fan driven by a gas turbine engine was mounted on the port wing of a test bed aircraft. The goals of this program were to demonstrate the Prop-Fan system while obtaining baseline structural and acoustic data during flight and ground operation to advance the understanding of a Prop-Fan in large scale. This paper presents the major findings of the structural portion of the test program. Blade dynamic strain measurements taken over a wide range of ground and flight operating conditions including the effect of nacelle tilt angle are presented. The flight test results establish trends in blade dynamic response with aircraft operating conditions and these trends are compared to Prop-Fan forced response predictions.