Thus, Russian pilots flew obsolete machines in combat throughout the war in the face of much better enemy aircraft. The fact that so many obsolescent machines remained in service produced Otryads that were an eclectic mix of aircraft; some front line, others nearly so, and some that should not have been flying. With so many different engines and airframes from French, British and Russian factories, trying to keep the machines flying was a constant challenge for Imperial ground crews. One report from the American War Department dated August 24, 1916 stated that, "The great majority of Russian machines are very dangerous to fly, due to the lack of proper over-hauling and having been tinkered with by inexperienced men. Lack of spare parts induced the Russians to fit magnetos and sparking systems to motors for which they were not built, and this makes the wear and tear excessive all around." The synchronization gear dilemma The Imperial Russian Air Service, in common with other World War I air services, struggled to find a way of allowing a machine gun to fire safely through the spinning propeller of an aeroplane. The Russian High Command was tardy in realizing the necessity for arming its aircraft throughout 1914 and 1915, leaving frustrated aviators using such impromptu armaments as pistols, rifles, trolled anchors and cables, and other makeshifts. Part of the delay was caused by a paucity of light automatic weapons that an aircraft could lift. However, it became apparent that the ability to aim both gun and aircraft simultaneously was a great advantage in aerial combat. In late 1915, Naval Lieutenant Victor Dybovsky of the 20th KAO invented a system of cam plates mounted on an engine's crankshaft that would prevent a machine gun from holing an aeroplane's propeller. Static tests at the Lux Aircraft Works proved its feasibility by November 1915; towards the end of the month, Morane-Saulnier G serial no. MS567 was forwarded to the 30th KAO for field testing. Poruchik Mikhail Shadsky flew test flights on both 9 and 29 December; cold thickened the machine gun's lubricant both times, preventing it from firing. When testing restarted in April 1916, Shadsky had more success. During April and May, he engaged the enemy about ten times. He shot down Austro-Hungarian aircraft on May 23 and 24 1916, but crashed to his death and his machine's destruction after the latter encounter. However, production of the