sentences:  On 1 December 1916, events had progressed to the point of the War Office formally requesting technical data from the motor company.Ball visited the Austin works that month.He recommended arming the plane with two Lewis guns mounted on the centre section, and firing above the plane's propeller; however, this arrangement was replaced by an installation patented by Herbert Austin, in which a Vickers machine gun fed by a 500-round belt of ammunition fired through a hollow propeller shaft, (A Lewis gun seems to have been actually mounted in this position in the prototype as completed).