Radial engines are smooth operating, tough, and reliable. These attributes endeared them to military use during WWII. However, a nuance of radial engines is that following shutdown they seep oil into the lower most cylinders. If this oil is not evacuated prior to restart there is a notable risk of engine damage through hydrolocking. Prior to start, it is common practice to purge this oil by manually pulling the props through... Booking Schedule: https://www.azcaf.org/location/salem-or-tour-stop/