Pratt &amp; Whitney R-1860-7 Hornet "B" 9-cylinder radial aircraft engine - sectioned  - San Diego Air &amp; Space Museum annex Gillespie Field
<a href="//commons.wikimedia.org/wiki/User:Jim1138" title="User:Jim1138">Jim1138</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>