Mark Wrathall wrote:
The fire loops used on commercial turbines are made up with

a cross section

like coax cable. The shield and core are solid metal,

separated by a low

melting point salt which insulates as a solid. When melted,

it conducts,

shorting the two conductors, and turning on the light in the

cockpit

(basically).

Sounds more like the twisted pair with a low melting temp

insulator, I think we are more interested in the fact that there
is something too hot or on fire than specifically where it is and
how hot it is... the outcome will be the same if we don't get our
butt on the ground. The fire detection loop was meant to be a two
state device; things are good or things are bad.

On the other hand, it may be simpler to implement the same

outcome on a more reliable basis with thermocouples.

KISS applies here. An interesting statistic I read in another forum

during a

similar discussion...
More forced landings and damaged airplanes / people are caused by false
indications of fire, than by fire itself. Nothing worse than stuffing it
down in a rough field and flipping it over, just to find out later that
there was nothing wrong.
John Slade

What you need is a light, a cheap video camera and cockpit monitor.

Paul Lamar

The site has a bunch of itty bitty video cameras and related stuff.  Maybe
it would help!
www.supercircuits.com/

Rick Bunnell
cvp@iowatelecom.net

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