Joseph Sailer Jr. was the son of Dr. Joseph Sailer and Mary Lowber Strawbridge Sailer. He served in the Marine Corps Reserves in the 1930s, and later worked for the Sperry Gyroscope Company. In 1940, he traveled to England with Frederic Vose on a secret mission to provide the Royal Air Force with the Sperry Bomb Sight. Sailer and Vose are shown above, together, standing in front of an airplane before their trip to England. In World War II, Sailer was the leader of a squadron of Marine Corps dive-bomber pilots. He was killed in combat at Guadalcanal on December 7, 1942.
The link below leads to a documentary video that shows scenes from Sailer’s trip to England for the Sperry Gyroscope Company in 1940 with colleague Fred Vose, to provide the new Sperry Bombsight to the Royal Air Force and instruct the RAF in its use. The movie, which is about 48 minutes long including an introduction recorded in 1994, is interesting for its views of destroyers, aircraft, RAF installations, and other scenes from that era. The movie shows a few views of Sailer and Vose themselves also. The gallery above includes photos of an identity bracelet and letter that I found among Sailer’s personal items. It appears that he used the letter and bracelet to enable him to take photographs and movies in connection with this project, in accordance with what must have been strict wartime regulations on photography.