Both Packard and Guiberson produced aircooled radial diesel engines. Packard didn't produce many, though one installed in a Bellanca set an unrefueled endurance record that stood, I believe, until the Voyager did the round the world effort a few years ago. Most Guibersons were used in ground vehicles. The most successful WW2 German diesel aero engine was the Junkers Jumo. This engine employed two crankshafts on top of each other and two sets of pistons, opposing each other in the same cylinder. My understanding is that it was a good but heavy engine.
Larry, I believe 100LL has 2gms/gal, not 8. 80/87 normally had .5gms/gal. Interestingly enough, the lower
grade of avgas had NO lead until the early '50s and one reason Franklin wanted owners to use unleaded
fuel.
I wonder if the EPA will mandate a smog device on these "new" aircraft diesel engines...in a few years, after they become popular.........at the cost of $????K?
Dan