The Aixro XF-40 (or XF40) is a German aircraft engine, designed and produced by Aixro of Aachen for use in ultralight aircraft.
The XF-40 is a single-rotor Wankel engine. It is a displacement, liquid-cooled, petrol engine design, with a poly V belt reduction drive with a reduction ratio of 1.25:1. It employs capacitor discharge ignition and produces at 6500 rpm.