https://www.flyer.co.uk/bullet-shaped-otto-celera-gets-ready-to-fly/
https://www.euroga.org/forums/aircraft/10897-celera-500l
The Drive reports that the FAA says the aircraft’s airworthiness was approved in February 2019 and that it uses the Raikhlin Aircraft Engine Developments (RED) A03 V12 turbodiesel engine.