You welcome
A little more on 37mm gun
In October 1918, the COW gun was installed in the rear cockpit of an Airco D.H.4, fixed and aimed up. The angle of the installation in at least one ( A2168 ) was about 80 degrees. The gun fired through a hole in the upper wing. The idea was to use this weapon against the large German bombers and Zeppelins, and after some reinforcement to prevent blast damage, testing was successfull. Three D.H.4s with COW guns were put into service. They carried a crew of two; the gunner in the aft cockpit not only loaded the weapon – the breech was inconveniently close to the cockpit floor – but also fired it on a signal from the pilot, who aimed with a ring-and-bead sight. Though two were sent to France, they did not see any combat before the war ended. (A2168 is recorded as flying a sortie against German Gotha bombers in August 1917, but that was presumably still without the COW gun.)
The french however were by far more entuasiatic about it and used in several Voisin airplanes.