The Waterworks Museum - Hereford and the Stirling Engine Society worked together throughout 2016 to celebrate the bicentenary of the Stirling engine. In 1816 the Rev Robert Stirling, a Scottish clergyman, filed his patent with a complete drawing of a new type of engine working purely on the heating and cooling of air. Within two years he demonstrated a working engine. The hot-air engine was born and, following rapid development on both sides of the Atlantic, had its heyday in the 1890s becoming known as the Stirling engine in honour of its inventor.
This summer Hereford has become the hub of the celebrations in Britain culminating in the largest gathering of Stirling engines in October. There is an annual rally every year in Hereford but this was something special with more than 120 Stirling engines on display. These ranged from miniature engines which worked from the heat in the palm of the hand to full-size examples of engines from the late Victorian period. Exhibitors came considerable distances, from Barnstaple to Norfolk, and from Halifax to Penzance. The rally was blessed with fine weather enabling the larger engines to be displayed working safely in the Museum grounds.
There is a marked resurgence of interest in the modern practical applications of Stirling engines. They are now much more efficient and can be made silent in operation. The Stirling cycle under which they operate can intriguingly be put into reverse. By rotating the engines mechanically they can produce very low, even cryogenic, temperatures. In this guise miniature versions are used to cool the magnets of MRI scanners.
The Museum has become a national centre of information and explanation of Stirling engines. New displays were installed in the Spring with colourful explanatory panels, interactive working models and a new video film illustrating Robert Stirling's pioneering work. The Museum itself has two full-size working Stirling engines manufactured by Hayward-Tyler of Luton in the 1880s. In addition, experimental thermo-electric generators, developed at Harwell in the 1960s and based on the Stirling cycle, are on display for visitors to see.
This magnificent gathering of Stirling engines really caught the public imagination and the visitor numbers far exceeded those for any previous autumn event at the Museum. On Sunday 8th October 2017 there will be another rally of Stirling engines at Hereford, so put the date in your diary now!