4 units - METRIC 80mm Winter altimeters - factory refurbished by Winter to the highest quality.
One of the primary instruments required for gliders is the Altimeter. Winter have been making Altimeter’s since the 1930’s and whilst the technology has not changed in 80 years, the materials have, leading to better accuracy and calibration. It has 3 pointers with one revolution equalling 1000 ft. The Altimeter is supplied with a form one and is accurate to 20,000 ft although it will indicate heights above 20,000 ft!
The science bit, how does it work?
The pressure-sensitive measuring element is a diaphragm capsule (aneroid capsule) which reacts to the effect of changing air pressure as the aircraft changes altitude. Tempered, aged copper-beryllium diaphragms ensure highly accurate readings. The diaphragm movement is transmitted to the instrument pointers by a linkage and gearwheels. A bimetal link compensates for the effect of temperature change delivering a highly accurate reading. The whole instrument is protected against shock and vibration.