Boeing-Vertol BV-347 Chinook [65-7992]
This can be described as a fixed-wing helicopter, not a common phrase in the aviation world!
It was evaluated for the Heavy-Lift Helicopter project in 1972 which led also to the creation of the enormous XCH-62.
This is a modified CH-47A fitted with a 9ft fuselage plug, four bladed rotors and, most remarkably, a variable geometry fixed wing.
Thankfully it has been preserved.
US Army Aviation Museum.