A detail of the Miller 4-cylinder 25 hp fan engine of the <a href="https://en.wikipedia.org/wiki/en:Caproni_Ca.1_(1910)" class="extiw" title="w:en:Caproni Ca.1 (1910)">Caproni Ca.1</a> Italian pioneer biplane, on display at the Volandia aviation museum in the province of Varese.
<a href="//commons.wikimedia.org/wiki/User:MLWatts" title="User:MLWatts">MLWatts</a>
<span class="int-own-work" lang="en">Own work</span>