It was called the TIFS (Total In Flight Simulator) and was built by Tex Johnson (of rolling the 707 fame) Incorporated in Santa Barbara, California in 1969. TJI shared a hanger with Aerospacelines that built the Guppies. I worked on TIFS from February to June 1969, my first job after getting out of the Air Force. The Convair fuselage was shortened, note that the forward entry door is gone in the photos below, a Boeing 707 nose was added along with side force surfaces on the wings. When the airframe modifications were complete the aircraft was taken to Cornell University where computes were installed that would mimic the handling of a 707. Things like engine outs could be exhibited by using the side-force surfaces.
Photo © Peter de Groot
While visiting a relative earlier in the week I came across some pictures I took in April 1969 while the TIFS was undergoing modification. How they ended up in a photo album of my sister and what happened to the rest of the pictures will remain a mystery.
Sorry about the photo quality but they were taken with my Petri 35 mm viewfinder camera and then I had to scan 42 year old prints.
One of the parts I installed was the external longeron that ran from the 707 to the Convair, it is visible in all three photos.