Curtiss-Wright proposed the Model 90 to the US Army for the AAFSS (Armed Aerial Fire Support System) contest circa 1965. The Model 90 was derived from X-19 design concepts, and was a VTOL vehicle that used four tilting prop-rotors for both VTOL and forward thrust. The Model 90 lost out to the Lockheed design, which became the AH-56 Cheyenne. It’s interesting to speculate how the USAF would have reacted had the Army selected the Model 90… it was, after all, a fixed-wing combat aircraft, and by this point the US Army was not supposed to have such things.
You can download a 5 megabyte JPG file of the artwork; the link is HERE. To access it, you will need to enter a username and password. The username: the first word in the body of the text on page 3 of APR issue V2N4. The password: the first word in the body of the text on page 5 of the same issue. Note that both are case sensitive.