I know, it’s probably a Percival Prentice, not a Chipmunk. Got confused because Hergé usually took some liberty with aircrafts in his comics, but there’s also definitely a “Chippie” in the “Black Island“. Red/white with a bubble canopy.
Anyway, you get it. A proper Chipmunk should run a DH Gipsy engine. And the guy who writes this cannot currently fly his plane because of Gipsy cylinder issues. Go figure…