Dale Laverne Knapp was born born at Humboldt, Richardson County, Nebraska on May 26, 1925. His parents were Roy Emanuel Knapp (27 Jun 1902 – Dec 1983), who was born at Holt County, Missouri; and Theresa Lee 'Tracy' (Gerdes) Knapp (22 Jan 1906 – 1988), who was born at Nemaha County, Nebraska. His parents married on April 29, 1922. He had four brothers: Hubert Leroy Knapp (15 Jan 1924 – 16 Aug 1981), Homer Knapp (abt 1928 – 2012), Beecher Emanuel Knapp (7 Sep 1932 – 7 Nov 1988), and Herschel Knapp (abt 1938 – 1995). From at least 1935 to 1940, the family lived near the Missouri River in rural Holt County, Missouri, where his father was a farmer. Sgt Knapp's home of record was 2337 Y Street West, Lincoln, Lancaster County, Nebraska, his mother's address in 1944.

He completed Army Air Forces aerial gunnery training, and was assigned as tail gunner on the heavy bomber crew of Lt Doyle L. Simons in the 838th Bomb Squadron of the 487th Bomb Group. The Simons crew completed B-24 crew training with the 487th Bomb Group at Alamogordo Army Air Base, New Mexico, and deployed with the Group to England in March 1944. They flew B-24H 41-29479 'The Big Bad Wolf' from Alamogordo, New Mexico to Lavenham, England via the southern Atlantic ferry route—a journey of about 10,000 miles—and arrived at Lavenham by mid-April 1944.

The 487th Bomb Group was based at U.S. Army Air Forces Station 137, near Lavenham, Suffolk, England, and was part of the 8th U.S. Army Air Force in Europe. After the Group arrived in England, Lt Simons was grounded with appendicitis, and was replaced as First Pilot by 2/Lt Lorin D. McCleary Jr.

On May 11, 1944, the McCleary crew took off from Lavenham in B-24H 42-52444 on a mission to bomb the railroad marshalling yards at Chaumont, France. The secondary target was Troyes. The 487th Bomb Group formation never reached the target. Navigational error resulted in the formation flying over accurate German flak guns guarding the airfield at Chateaudun, France. Sgt Barboza and eight of his crewmates were killed in action when their aircraft was shot down by flak over Chateaudun. Sgt Cosme Marquez, a friend of Sgt Barboza, was flying with Lt Olen Huff's crew in B-24 41-29525 off McCleary's right wing. He said: "McCleary’s plane was hit 25 or 30 yards to our left. I saw the waist gunners struggling to get out. I was yelling, ‘Bail out! Bail out!’ but they didn’t make it. Barboza was on his fifth mission and was killed in the ball turret."

The aircraft took a direct flak hit in the nose and flight deck and started burning at the engines. It went into a dive, exploded in the air, and crashed three kilometers east of Varize near Bazoches-en-Dunois. One man, Staff Sergeant Harold E. Owens, survived. He wrote: "At approximately 1145 we were hit by flak in the nose, which resulted in the death of Lt Victor Kramer, navigator, Sgt Paul Churm, top turret gunner, and S/Sgt Eugene McKee, radio operator. The plane immediately burst into flames, we were flying at an altitude of approximately 11,000 feet, a few seconds later the plane started into a dive, and exploded in mid air, with the result that I was blown clear of the plane. I managed to pull my ripcord and landed eight miles north of Chateaudun, France. I made a safe landing and at a distance of one quarter of a mile I saw the plane completely wrecked and on fire. I was the only member of the crew who parachuted to safety. I did not go near the plane because I knew the bombs had not exploded. I hid in the woods and about five minutes later the bombs exploded."

The dead were recovered by German troops, who buried them at the Grand Cimetiθre in Orleans, France. After the war, Sgt Knapp's remains were reinterred at Epinal American Cemetery, France.

B-24H 42-52444 crew:
• McCleary, Lorin D – 2/Lt – Pilot – KIA
• McCoy, Ernest E – 2/Lt – Copilot – KIA
• Kramer, Victor S – 2/Lt – Navigator – KIA
• Perry, Joseph D – 2/Lt – Bombardier – KIA
• Owens, Harold E – S/Sgt – Engineer – POW
• McKee, Eugene – S/Sgt – Radio Operator – KIA
• Frey, Arthur C – Sgt – Nose Turret – KIA
• Churm, Paul K – Sgt – Top Turret – KIA
• Barboza, Clemente M – Sgt – Ball Turret – KIA
• Knapp, Dale L – Sgt – Tail Turret – KIA

Source of information: Paul M. Webber, www.findagrave.com, www.abmc.gov