They’re called Coffman engine starters [1].

Random fact: Those starters are a plot point in the 1965 film The Flight of the Phoenix, where the protagonists are trying to start a plane that’s stranded in the Sahara, but only have a small supply of starter cartridges left.

[1] https://en.wikipedia.org/wiki/Coffman_engine_starter

I lived for a while on a sailboat equipped with an ancient Saab tractor engine (8 whole horsepower!). Was designed for cartridge starts in cold weather, though someone had fitted an electric starter by the time I saw it

Not just radials. The Napier Sabre H24 engine in Typhoons used cartridges as well.