[M] A VERY RARE WW2 RAF-ISSUE PORTABLE ALTIMETER CALIBRATOR BY R.W. MUNRO, No.130 CIRCA 1939

A VERY RARE WWII RAF-ISSUE PORTABLE ALTIMETER CALIBRATOR BY R.W. MUNRO, NO.130 CIRCA 1939

constructed in brass with japanned finish, the cylindrical pressure chamber with three circular viewing ports, external electrical contacts supplying internal lighting, circular access hatch with wheel operated 'O' seal, the endplate with valve assemblies for the application of positive and negative pressure feed, pressure relief valve, impressed Air Ministry property mark 'AM' surmounted by a crown, internally, white painted with lamp fittings, removable instrument holder, supported on twin cradles affixed to a mahogany plinth with maker’s plate and mahogany lid with screw fixings -- 9½ x 19½ x 9½in. (24 x 49.5 x 24cm.)

These instruments were ordered by the RAF from Munro to meet the substantially increased demands made upon testing facilities brought about by the rapidly increasing number of operational airfields. Very few of these are known and it is estimated that total production did not exceed 500. It is likely some were sent to allied countries -- one example has been found in Australia and another in the USA. In all, five are currently thought to exist.