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08-12-2012, 07:01 PM
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Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,458
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Electrical Scare!
...We had as it turned out, a small problem while returning from a $100 hamburger trip today. I decided to post it here to see if I were the only one or if others have seen this. It was very hot here in southern California today and upon returning to my plane the inside temperature of the cockpit was upwards of 140 degrees. We lifted off for the return trip home and immediately detected a new, unfamiliar smell resembling that of ethylene glycol that proceeded to get worse rapidly. My friend Bill noticed the voltage meter was falling and at that point we equated the smell with an electrical short and begun to fear fire and shut down all electrical via the master. The smell quickly dissipated. After landing I started searching for the problem and isolated it to the volt meter itself. When you show it 12 volts, it reads only ten and after 20 seconds it falls off to read zero. At that point it becomes so hot on the back of the gauge that you can't touch it and it begins to smoke and stink. I am relatively sure, if left with power applied it would soon burst into flames, and most certainly ruin my day. This is one of the $36 Vans 2 1/4" steam gauges and the cost isn't a problem but the potential for disaster is. This didn't pop a breaker or set off a warning of any type, and is most likely an isolated incident. At least I hope this is the case! If others have seen this please let me know. Thanks, Allan... 
__________________
Allan Nimmo
AntiSplatAero.com
Innovative Aircraft Safety
Products, Tools & ServicesInfo@AntiSplatAero.com Southern California (KREI)
RV-9A / Edge-540 
(909) 824-1020
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08-12-2012, 07:22 PM
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Join Date: Oct 2008
Location: Utah
Posts: 8,151
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I had similar experience with Lucas voltmeter during Phase One. The same symptoms but without melting the gage. After dissassembling I found a burnt part then ordered new gage. Still working.

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08-12-2012, 09:12 PM
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Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
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Quote:
Originally Posted by PerfTech
...We had as it turned out, a small problem while returning from a $100 hamburger trip today. I decided to post it here to see if I were the only one or if others have seen this. It was very hot here in southern California today and upon returning to my plane the inside temperature of the cockpit was upwards of 140 degrees. We lifted off for the return trip home and immediately detected a new, unfamiliar smell resembling that of ethylene glycol that proceeded to get worse rapidly. My friend Bill noticed the voltage meter was falling and at that point we equated the smell with an electrical short and begun to fear fire and shut down all electrical via the master. The smell quickly dissipated. After landing I started searching for the problem and isolated it to the volt meter itself. When you show it 12 volts, it reads only ten and after 20 seconds it falls off to read zero. At that point it becomes so hot on the back of the gauge that you can't touch it and it begins to smoke and stink. I am relatively sure, if left with power applied it would soon burst into flames, and most certainly ruin my day. This is one of the $36 Vans 2 1/4" steam gauges and the cost isn't a problem but the potential for disaster is. This didn't pop a breaker or set off a warning of any type, and is most likely an isolated incident. At least I hope this is the case! If others have seen this please let me know. Thanks, Allan... 
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What size fuse/breaker did you have installed in the instrument supply line?
This should have blown if the current drawn was large enough to generate that much heat.
Van recommends a fuse/breaker in the supply, but I'm not sure if he gives a value...
http://www.vansaircraft.com/pdf/Gauge_Install.pdf
__________________
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ
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08-12-2012, 09:47 PM
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Join Date: Oct 2005
Location: Melbourne, Australia
Posts: 1,868
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Quote:
Originally Posted by PerfTech
My friend Bill noticed the voltage meter was falling and at that point we equated the smell with an electrical short and begun to fear fire and shut down all electrical via the master.
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Allan, Vans cheap chinese steam gauges are notoriously shonky. You might have been a bit lucky that things did not get worse.
If you haven't got one, I highly recommend a small Halon fire extinguisher for the cockpit. A quick squirt up behind the panel in flight if required could stop a very small electrical fire from rapidly growing into a catastrophe. Once a flame has developed, cutting power will invariably not stop it spreading.
__________________
You’re only as good as your last landing 
Bob Barrow
RV7A
Last edited by Captain Avgas : 08-13-2012 at 06:52 AM.
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08-12-2012, 10:03 PM
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Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,458
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Quote:
Originally Posted by az_gila
What size fuse/breaker did you have installed in the instrument supply line?
This should have blown if the current drawn was large enough to generate that much heat.
Van recommends a fuse/breaker in the supply, but I'm not sure if he gives a value...
http://www.vansaircraft.com/pdf/Gauge_Install.pdf
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...I have one of the ceramic so called smart power panels that should have shut down this circuit at 3.5 amps. I wish it had individual breakers and old school switches instead. Allan... 
__________________
Allan Nimmo
AntiSplatAero.com
Innovative Aircraft Safety
Products, Tools & ServicesInfo@AntiSplatAero.com Southern California (KREI)
RV-9A / Edge-540 
(909) 824-1020
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08-12-2012, 10:04 PM
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Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,458
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Quote:
Originally Posted by Captain Avgas
Allan, Vans cheap chinese steam guages are notoriously shonky. You might have been a bit lucky that things did not get worse.
If you haven't got one, I highly recommend a small Halon fire extinguisher for the cockpit. A quick squirt up behind the panel in flight if required could stop a very small electrical fire from rapidly growing into a catastrophe. Once a flame has developed, cutting power will invariably not stop it spreading.
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...I will get one this week. Thanks, Allan... 
__________________
Allan Nimmo
AntiSplatAero.com
Innovative Aircraft Safety
Products, Tools & ServicesInfo@AntiSplatAero.com Southern California (KREI)
RV-9A / Edge-540 
(909) 824-1020
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08-12-2012, 10:11 PM
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Join Date: Apr 2005
Location: KSLC
Posts: 4,021
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Quote:
Originally Posted by Captain Avgas
If you haven't got one, I highly recommend a small Halon fire extinguisher for the cockpit. A quick squirt up behind the panel in flight if required could stop a very small electrical fire from rapidly growing into a catastrophe. Once a flame has developed, cutting power will invariably not stop it spreading.
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Happily, the aircraft wire that most of us use, has insulation, that will just melt off a red hot wire. And if other components of the panel aren't too prone, to easily igniting, you'll have a good chance of no farther damage.
I actually tested this out (not by choice)............before the plane ever flew. I had installed a heavy duty relay, intended to cut power from the alternator B-lead, in cause of a runaway alternator. This particular circuit, was later scrapped by the designer. What I didn't know, is that the relay contained several diodes, that were supposed to be removed for this application. As I sat in the cockpit, and turned on the power.........there was a big puff of smoke, followed by hot melting insulation falling on my trousers, just above the knees. I actually had a direct short, to the main ground wire, which is a #4, as I remember. It was bundled with many others, but the others were not effected. This is aircraft wire, with the white insulation. I no longer know the particulars, & name of insulation. The wire itself, was nearly melted through.
Note: I suppose we could conduct a flame test on Van's instruments, to see how well the support combustion, or not.
L.Adamson
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08-12-2012, 10:14 PM
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Join Date: Mar 2007
Location: Sonoma County
Posts: 3,821
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Quote:
Originally Posted by Captain Avgas
Allan, Vans cheap chinese steam guages are notoriously shonky. You might have been a bit lucky that things did not get worse.
If you haven't got one, I highly recommend a small Halon fire extinguisher for the cockpit. A quick squirt up behind the panel in flight if required could stop a very small electrical fire from rapidly growing into a catastrophe. Once a flame has developed, cutting power will invariably not stop it spreading.
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There you go Allen...... we need a source for an honest priced small (one hand) Halon extinguisher.
You can do this........................ 
__________________
VAF #897 Warren Moretti
2019 =VAF= Dues PAID
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08-12-2012, 10:16 PM
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Join Date: Dec 2011
Location: Meridian ID, Aspen CO, Okemos MI
Posts: 2,645
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Allen, you have to do a cool video showing how to use it - then I will buy!
__________________
rockwoodrv9a
Williamston MI
O-320 D2A
Awaiting DAR Inspection
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08-12-2012, 10:47 PM
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Join Date: Nov 2005
Posts: 1,256
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__________________
Steve "Flying Scotsman"
Santa Clarita, CA
PP-ASEL, ASES, Instrument Airplane
RV-7A N660WS flying!
#8,000
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