British, WW1 - c.1914–1918, RAF Bomb Sight Reversing Stopwatch, by S. Smith & Son Ltd, London

*British, WW1 - c.1914–1918, RAF Bomb Sight Reversing Stopwatch, by S. Smith & Son Ltd, London*

An unusual and highly specialised British military bomb sight reversing stopwatch by S. Smith & Son Ltd, London, believed to date from the First World War period and associated with early aerial bombing calculations and observation duties. The watch is housed in a 50mm gun metal finished case with rotating outer bezel incorporating an internal indicator pointer.

The white enamel dial is signed S. Smith & Son Ltd, London and prominently marked: “Reversing Stop Watch for Equal Distance – Bomb Sight – Height in Thousands of Feet”. The calibrated dial and reversing mechanism were intended for use in aerial bombing calculations, allowing operators to determine release timing and equal-distance corrections according to aircraft altitude and ground speed. Such instruments represent an early phase of military aviation navigation and bombing technology during the formative years of the Royal Flying Corps and early RAF operations.

The watch retains a high-grade traditionally finished English frosted gilt movement. The presence of solely English “Slow” and “Fast” markings to the regulator confirms manufacture for the British market and strongly suggests wartime procurement for military aviation use, likely supplied through one of the established Coventry or Birmingham horological workshops fulfilling War Department contracts during the Great War period. Matching assembly number “11” is stamped to both interior case sections, confirming the bezel, body, and rear cover remain together as an original matched set.

The white enamel dial survives in notably well-preserved condition for a First World War aviation instrument, retaining crisp black calibrations and lettering with only faint hairlines visible near the upper edge. Unlike many surviving wartime cockpit and observation instruments, it appears to have escaped major service damage or restoration.

Approx. Measurements – Case diameter: 50mm.

Operational Context:
Instruments of this type were used by observers and bomb aimers during early aerial bombing operations. The observer would track a ground target through the bomb sight and activate the reversing mechanism as the target crossed calibrated reference points. Using aircraft altitude, measured in thousands of feet on the dial, together with airspeed and timing calculations, the watch enabled determination of the correct “equal distance” release point to compensate for forward motion and drift, improving bombing accuracy during the pioneering era of military aviation.

History Note:
S. Smith & Son Ltd of London became one of Britain’s foremost manufacturers of precision timing and aviation instruments during the late Victorian and early aviation eras. During the First World War the firm supplied specialised cockpit timers, navigational instruments, and military stopwatches for aviation and artillery applications. Bomb sight stopwatches of this type are comparatively scarce survivals owing to their specialist operational role and limited production compared with standard military pocket watches.

*Condition*
Gun metal finish showing age-related wear and surface rubbing throughout. Enamel dial generally very well preserved with some faint hairlines and light marks near the upper section. Rotating bezel and internal indicator pointer intact. Side pushers and crown present. Frosted gilt movement clean in appearance. Watch currently running when wound although untested for long-term accuracy or duration. Please see photographs as part of the condition report.

JAQ#3267#CAO_17062026