Charlie
Kohler wrote:
Several
months ago I was removing my exhaust system for top overhaul/Jet Hot coatings
and was particularly interested in my firewall blanket and several areas of the
aluminized coating had come loose and or off. I started to remove some of it
and I discovered that BEHIND a perfectly normal piece of the blanket I had a
blackened/totally charred 6 inch in diameter piece of pre-preg firewall. ------deleted
text---
I
am currently looking at--
http://www.acroname.com/robotics/parts/R67-UVTRON.html
backed
up (verified) by a standard outside air temperature gauge placed in gascolator
area.
Anyone
have a better idea?
Charlie,
I installed a “standard” temperature sensor (-50 c to 150 c) in the
back of the engine compartment just inside each of the exhaust stacks. (Lancair
IV-P/TSIO-550E), and wired them to my Electronics International MVP-50. I made the
brackets out of aluminum channel and fastened them to the motor mount with Adel
clamps. I didn’t do a lot of research or testing for placement…just
put them where I thought an engine fire would deliver flame and heat out the
tunnel if same was to occur. I was particularly interested in having the probes
indicate an oil fire around the turbos, but also wanted to detect any abnormal
heat exiting the exhaust tunnels. Like elephant repellant here in northern VA, they
seem to be working very well… J
A fire/flame sensor would seem an additional benefit, but may
not be required to achieve a high level of assurance for any abnormal heating
conditions in the engine compartment? … I hope that the norm would be a
broken exhaust pipe, blown gasket, etc that heated without a flame source! In
any case, after monitoring the probe results for a number of flights, I alarmed
them on the MVP-50 display/audio for 170 F, and have monitored the temps over
about 420 flying hours so far. I have never had an “over temp”
alarm from these probes, nor have I had any cracks/failures in the engine
compartment that generated excess heat, so I really don’t know if the
system works as intended. Still, I am pretty confident that it will give almost
immediate warning of a fire or serious over heat that dumps hot gas out the
exhaust tunnel. If you already have any digital instrumentation installed,
adding these probes could be very simple. The available audio alarm is a great
feature of most of these systems.
The probes register between 100 and 130 F degrees in cruise,
just a few degrees higher during climb (depends on the OAT and climb speed, as
you would expect). The hottest readings are just before/after engine shutdown…up
to 150 F on rare occasion; normally 140 max. I am not sure why this is the
hottest period, but suspect that it’s also the hottest time in the rest
of the engine compartment as well, as the cooling airflow is turned off while
the turbos/exhaust system is normally still pretty hot. (I don’t run the
engine at idle for any specified time after landing unless I do a go-around/stay
in the pattern; normally the engine is very cool at touchdown—as monitored
on the MVP-50)….
Did I mention that I really like this little MVP-50..probably
the most useful instrument in my EFIS panel?
Glad to provide pix if helpful.
Bob