While looking up info on the Mann & Grimmer M.1 found out that in 1914 the Edward brothers had patented a synchronizing gear to enable guns to be fired through the revolving airscrew of a tractor airplane, their Patent was No.23790 A.D. 1914. For some reason best known to the War Office, whence a working model of the gear was sent, no more was heard of the device.
Interesting you just hear about the Germans doing it.
Chris