Cook Mk I Vintage Glider Compass by Cobb-Slater Instruments

Another interesting and we believe scarce item that may appeal to the vintage gliding community. Manufactured by Cobb-Slater Instrument Company who were based in Matlock, Derbyshire, England, who made a variety of instruments between 1940 and 1960 for use in gliders and sailplanes. We have discovered various company advertisements from the period indicating they supplied amongst other things variometers, barographs, venturis and water Traps as well as the Cook Compass Mk I as our example.

This compass, which sits in gimbals (the earlier version did not) and was designed to avoid the compass oil rotating in the instrument when the glider banking tightly in thermals so despite the strong movement the instrument would still give an accurate reading. Interestingly the 'East' and 'West' compass points on the dial are reversed so we assume when the when the dart shaped pointer is pointing West it indicates the true heading of the sailplane is actually West not East as you would expect; of course visa versa applies when pointing to East. The instrument is not dated but the data plate indicates serial nos 965 and a patent applied number of 20912. The body of the compass shows some wear to the paintwork but the compass needle correctly indicates North although we cannot guarantee its accuracy and like all our stock is for sale as a collectable only but it may be possible to make it airworthy again to soar in an appropriate vintage glider cockpit. Whilst a modest size at 2.25" from dial to base (5.5 cm) and 1.5" diameter across the dial (4 cm) we have never seen another offered for sale so grab it whilst you have the opportunity as we are unlikely to find another!