We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember saying
something like:

Yup, Thielert engines are used by Diamond aircraft.
http://www.centurion-engines.com/
Diesel engines running on aviation kerosene.

Only thing though - sooner or later, you can absolutely guarantee some
numpty ******* will fill it and run it (albeit briefly) on petrol.
TBO, iwt, for that, surely?