Steve,
You are correct that there is a
commonality. So far everything is on the endurance buss. Also I have
disassembled the forest of tabs and am cleaning it up and will do the same for
the battery connections. The wires coming to the forest of tabs looks
like a rats nest, so I am going to at least dress it up a little. I have previously
replaced both the power and ground wires to the transponder. I may replace
the ground wires to the other “victims” when I dress up the ground
wires.
I have never seen any voltage fluctuations
incoming to the transponder when it craps out. At first, I thought it was
getting hot and shutting down, but if it does get hot, it is supposed to just
reduce the frequency of response to interrogations. I pulled it out and
took it to a radio shop. They put it on their bench for two days and it
never shut down.
It is something in my plane but I haven’t
found it yet.
My annual is due in Jan. I will
replace the Aeroquip fuel hose then. Looks like I will not be doing much
flying in between.
B2
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Steven W. Boese
Sent: Saturday, December 08, 2012
10:09 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Engine
Ground changed from Aeroquip hose
Bill,
You are correct that my battery is in the
cockpit. Since you have multiple devices that are having problems
simultaneously, it might be good to check things that are common to all of
them. The likelihood of loosing several ground or supply
connections at the same time seems remote. In other words, check the
connection of the forest of tabs to the battery ground before
worrying about the individual tabs.. Also, since you have two
batteries, it seems unlikely that the problem would be happening within
both of them at the same time. Are the batteries connected to the
positive side of the system through separate contactors? If so,
are both contactors closed when the problem occurs? If both batteries
are connected through one contactor, that could be a common
point of failure.
Steve
From: Rotary
motors in aircraft [flyrotary@lancaironline.net] on behalf of
Bill Bradburry [bbradburry@bellsouth.net]
Sent: Saturday, December 08, 2012
6:06 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Engine Ground
changed from Aeroquip hose
Steve,
My two batteries are mounted on the engine
side of the firewall. I presume yours is mounted in the cockpit? I
had not considered a loose connection inside the battery. I plan to clean
up all the connections outside the battery.
I have had a VOM connected to the supply
side of the transponder when it went off and I did not see any fluctuation in
the voltage when that happened. Several folks have suggested that I have
a grounding issue so I am cleaning all of them up. I previously replaced
both the power and ground wires to the transponder but that had no affect.
I am not certain how to check each ground
wire going to the forest of tabs. Anybody have a suggestion?
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Steven W. Boese
Sent: Saturday, December 08, 2012
4:52 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Aeroquip
hose
Bill,
From your description, your ground
architecture sounds very similar to mine. I have the forest
of tabs bolted to the firewall with a brass bolt. On the cabin side,
the battery ground is connected to this bolt. Everything else grounds to
the forest of tabs. On the engine side of the firewall, the engine ground
is connected from the front (in the car) cover to that brass
bolt. My arrangement has not had any electrical problems that I am
aware of.
I also have a stainless wire braid covered fuel
line from the firewall bulkhead fitting to the fuel rail on the engine. I
have seen no damage to it. The fact that your wire braid on the fuel line
has been burnt suggests that it might have intermittently served as the
engine ground at one time or another. The braid must not have conducted a
large current for very long or it would been destroyed completely. I
can't think of a worse place to have an uncontrolled resistance heater than on
that fuel line. Verifying the integrity of the ground from the engine to
the airframe and from the battery to the airframe certainly seems like
a worthwhile endeavor.
Depending on the details of the alternator
installation, an intermittent connection inside the battery also might be a
possibility although this would not explain the damage to the fuel line braid.
FWIW
RV6A, 1986 13B NA, RD1A, EC2