Inside the Cowling Fire / Heat Detector?

How about your nose?

Fortunately, I've never had a fire in an airplane - flying or not.
However, a few years ago I was flying along at economy cruise
(fairly low altitude, as I was enjoying the scenery), when suddenly
something smelled hot. No smoke, but something obviously was amiss.
Of course I headed for the nearest airport. After landing and
shutting down, an inspection soon revealed the source of the
smell - scorched paint on the cowling. It seems that the left
exhaust collector had blown out a hole the size of a quarter
on the side nearest the cowling. Needless to say, that event
could have produced much more excitement than it did.

Another time on a trip in severe clear weather I decided to
descend - once again to get a better look at the scenery. After
leveling off (at 2500 feet, as I recall), I noticed that it had
suddenly become very hot in the airplane. It smelled hot - and
the air coming out of the footwell vents was too hot to hold
my hand in front of. Again, I headed for the nearest airport
and landed - and took off the top cowling to see what was going
on. There was nothing wrong with the airplane. It seems that I
had descended into an inversion layer that must have had temps
of 110 degrees or more (believe it or not this was in Oregon,
and I landed at Astoria). That day it was 114 in Portland!
It was so hot in the motel I stayed in (no air conditioning -
they don't need it there - ha ha), that everybody sat outside
until late in the evening.

Bottom line - if something is too hot in the engine compartment
of a single (front engine, of course), you will know about it
at once!

David Johnson