Oh I know, that is why they make a strange "blat blat" note, but in the strange world of motorcycles uneven firing gives better traction than even firing does. Especially with the Moto Guzzi the exhaust note makes you think it would vibrate like hell whereas it is smooth as silk.
I remember reading about a couple of OL-1A that were still being used in the area pf the Philippines, but they were in civilian hands before the war. I do not know if they did any flying after the war started, either in civilian or military hands. I do not remember the name of the company that they belonged to.
I have owned both of exactly the same displacement, Triumph 750 (360 crank) and Kawasaki 750 (180). The Triumph was much more "rideable" especially in the wet, the Kawasaki vibrated less but the vibrations were far more annoying despite it having balance shafts to reduce it. I went as a pillion on both a Ducati 860 and a Moto Guzzi 850, despite all the noise they make they hardly vibrate at all.
I had a T120V and a T140V (bought new 1977 silver jubilee edition) and a Norton 500SS. A friend of mine had a Norton 650 Dominator, that really was the dogs goolies, not only did the featherbed frame handle like a dream it also seemed to isolate a lot of the vibration.
I would like to tell you how it went, but after 1050 miles "Sue" did a right turn in front of me and wiped us both out 50 miles after it was "run in". Myself and the girl on the back survived, the bike and the car didnt.
Probably already stated (sorry, didn't read through the thread), but both the Fiesler-Storch and the BF-108 were powered by the same inverted Argus V-8 engine. Argus As 10 - Wikipedia
Same bore and stroke were used by Cummins for their NH series engines.
Back when I worked on the big trucks, I used to joke that if you welded two of those together, you'd have an Allison V-12.