Now THAT'S a Spinner!

[BusyLittleShop]

Spinning the engine helps, but you still need to have cool air coming in. If the engine is spinning inside a box of hot air, the air will be circulating but it won't do much cooling.

True Dana... if the engine were confined inside a box a rotary would
be spinning in its own heat of combustion and exhaust but that is not
what we see on the Morane Saulnier... the designers engineered a gap
between the spinner and cowl to allow a path for cooling air to enter
and at bottom there is no cowl what so ever which is another design
feature to allow the cylinder to exhaust in the exposed air stream...
technically speaking I don't see a possible problem of over heating
rather I see a number of novel measures taken by the engineers to
sufficiently manage precious cooling air...