Editing Synchronization gear (section)

==== The Vickers-Challenger gear ====
[[File:RE 8 with Vickers Challenger.jpg|thumb|left|Much neater, more practical application of the Vickers-Challenger gear for the synchronized Vickers gun of an R.E.8]]
The first British synchronizer gear was built by the manufacturer of the machine-gun for which it was designed: it went into production in December 1915. [[George Henry Challenger|George Challenger]], the designer, was at the time an engineer at Vickers. In principle it closely resembled the first form of the Fokker gear, although this was not because it was a copy (as is sometimes reported) it was not until April 1916 that a captured Fokker was available for technical analysis. The fact is that both gears were based closely on the Saulnier patent. The first version was driven by a reduction gear attached to a rotary engine oil pump spindle as in Saulnier's design and a small impulse-generating cam was mounted externally on the port side of the forward fuselage where it was readily accessible for adjustment.<ref name=Woodman9>Woodman 1989, pp. 187–189.</ref>

Unfortunately, when the gear was fitted to types such as the [[Bristol Scout]] and the [[Sopwith 1½ Strutter]], which had rotary engines and their forward-firing machine gun in front of the cockpit, the long push rod linking the gear to the gun had to be mounted at an awkward angle, in which it was liable to twisting and deformation as well as expansion and contraction due to temperature changes.

For this reason the [[Royal Aircraft Factory B.E.12|B.E.12]], the [[Royal Aircraft Factory R.E.8|R.E.8]] and Vickers' own [[Vickers FB 19|FB 19]] mounted their forward-firing machine guns on the port side of the fuselage so that a relatively short version of the push rod could be linked directly to the gun.

This worked reasonably well although the "awkward" position of the gun, which precluded direct sighting, was initially much criticised. It proved less of a problem than was at first supposed once it was realized that it was the aircraft that was aimed rather than the gun itself. The last aircraft type to be fitted with the Vickers-Challenger gear, the R.E.8, retained the port-side position of the gun even after most were retrofitted with the C.C. gear from mid 1917.