Another from the stash of largely-Grumman concept art, a lift-fan equipped VTOL aircraft, probably a ground support plane. The terrain is clearly Viet Nam inspired, so I’d put this in the second half of the 1960’s.
Note the complete lack of markings. This may indicate that the painting was photographed while still in a “neutral” stage, where markings could be applied aimed at specific customers. The Marines would seem an obvious choice, but in the mid 1960’s it was still a believable possibility that the Army could be equipped with aircraft such as this.