One of Raspet's early projects was the study of Boundary Layer Control (BLC). This involved a suction device that pumped the air out of the wing of the department's L-19 Birddog through a series of thousands of tiny holes, which greatly improved the low-speed flight characteristics of the aircraft. The aircraft had been further modified with a bubble observation canopy made by Mel Swartzberg, and one of Joe's duties was to observe the reaction of the cotton tufts that were glued to the wing while in flight. In order to do so, Joe had to unstrap himself from his seat to stand in the observation position. One one occasion, the aircraft went into a severe stall and banked hard to one side, throwing Joe from his position and nearly out of the plane...a close call.

Mel Swartzberg recalls that Joe did not care too much for flying himself, and left that role for Mel. Joe could manage the flying part well enough, it was the landings that constantly shook him up. It was up to Mel to bear the brunt of the flying duties. Mel was flying Joe in one of the department's TG-3A sailplanes that was battery powered, when Joe noticed that the sailplane was on fire, caused by a short from faulty wiring. Joe began to yank the wiring from the aircraft, attempting to do so without panicking and alerting Mel. After becoming aware to the crisis, Mel then put the aircraft into a slip in an effort to blow out the fire. When asked how the manuever was working, Joe replied, "Great! Now slip it to the other side!" The two were lucky to make it back to the ground safely, where they were greeted by Jerry Benoist, who had run to the landing spot and proceeded to douse Joe in the face with a blast from a fire extinguisher while attempting to put out the still lingering fire.

Another ill-fated flight for Joe occurred in the L-19 Birddog with former USMC test pilot Thomas S. Moore. While executing a full-flap, high angle of attack take-off, the flap handle disengaged, click-click-clicking its way down the selector to a no-flap position. The L-19 dropped like a rock, and nosed over on the end of the runway. Joe's wife Grace had a premonition that morning that something would go wrong, and she happened to pull up at the airport as the plane went down. Luckily, both Cornish and Moore escaped injury.

Joe was also involved with a research project in Lakehurst, New Jersey, that studied the aerodynamic properties of the tail sections of military blimps. It was discovered that the tail control surfaces of the blimps were largely ineffective at high angles of attack due to the disruption of air caused by the wake of the blimp's nose. It was discovered that only the outer portions of the tail fins were effective. This was made painfully obvious after one of the blimps lost a 3-foot section of its tail while exiting a hangar in Alabama, and flew despite the damage. It took quite a while for the blimp to maneuver back to a position to land without that crucial section. While at Lakehurst, Joe's wife would send care packages to her husband. In one such package, she sent Joe a large confederate flag. He found the occasion to "hijack" one of the blimps, hoisted the flag from the tail of the craft, and then informed the crew at Lakehurst over the blimp's PA system that "Col. Cornish has captured the blimp in the name of the Confederate Air Force."

Cornish left the department for one year to work for NACA (National Advisory Committee for Aeronautics), but returned to complete his Ph.D., with Gus Raspet as his advisor. With the death of Raspet in April 1960, Joe was left alone to complete his work. Dean Harry Simrall would provide the moral support needed, and Joe was granted his Ph.D. by an outside review board, the first Ph.D. for the School of Engineering. Joe was then named head of the Aerophysics Department, succeeding Raspet.

Cornish left the department in 1965 after serving as Head for 5 years. He then went to work as the Associate Director of Research for the Lockheed Corporation, and later became Director of Research. He is now retired and lives in Marietta, Georgia.