The alternator checked out OK. The last flight I flew I left both the
fuel pumps on
the whole flight. Usually, I only use both when on take off and landing.
Maybe the
current draw was too much for the 40 amp alternator. The guy at the
alternator shop
said that at and above 2/3 the rated current, the voltage starts
to drop off. Hmm. I have two of the fuel pumps that Tracy sells, I
don't know what the current draw on them is, a dynon D10- 1 amp
aproximately, Xcom radio- . 5 amp, Terra transponder- .75 amps,
EC2 and EM2- ? amps, 4 LS1 coils- ? amps and two 18 AH saturated
mat batteries. Maybe time to do a current check on the batteries
and trade one out for a new one. I have a new one, the old ones
are coming up to two years old. I have them on a float charger
anytime I'm not running the engine. Any thoughts?
Brian Trubee
You need an ammeter.
Paul Lamar
Brian,
In my opnion you do not need a ammeter as only more
weight! The voltmeter will tell you what state your battery is, you
do not really need to know what the alternator is putting out. If
the voltage is going down and the alt is OK then you alt is not up
to the job! as dale? said put a clamp-on the alternator output and
turn EVERYTHING on and watch the voltmeter and if the draw is more
than say 30 amps get a bigger alternator or ditch some of the load.
John Burey . Get realistic John. The weight is
ounces. You cannot have too much information. An ammeter gives an
instant early warning of what can happen. If suddenly the ammeter
shows a discharge the EFI and electronic ignition engine is going
to stop sooner or later. You can then turn off non essential
electric devices to give you more time to land. You will instantly
know if you have solved the problem. You can't just pull over to
the side of road and stop.
Paul Lamar
I generally don't like to wire an amp meter in the instrument panel
as it would require either a 8 or 6 AWG gauge wire for a maximum
curare of 40a or 50a, respectively .
A good alternative is to wire in a low voltage warning light in addition
to the
voltage meter.
Joel
Another alternative is have a red warning light come on when there
is discharge condition.
Paul Lamar
Use an induction coil ammeter with the coil around the main
battery wire. Simple, just needs to be calibrated.
Kevin Alderman
Paul is correct with the idiot light. Use a LED red. Takes up
almost no space in the panel and is highly visible when there is a
problem. Check the voltage the LED is designed for and install a
dropping resistor in series if required. A lower resistance will let
it be brighter. Small wire from alternator light terminal to the LED,
which saves weight. Note my previous post with Bosch fuel pump
amps. Could be between 5A and
15.5A. If yours are in the 15A range times two is 30 plus the panel
and don't forget lights. You could be at the 40A output. You need to
try a clamp-on amp meter for test to verify. Even if you measure the
pump amps times 2.
Dale Davies
WTF if weight is an issue empty the change in ya wallet, take a pee
before flying, Do your checks, look at your gauges, then fly. you
know better mate, c'mon. Knowledge is power.
Graeme Riley
Let me join in here. Our club planes have had a couple of instances
where the alternator gave up the ghost, and the ammeter indicated a
discharge, but the pilot and instructor pilot did not notice the
little needle moving the wrong way with no other indication -- until
the radio's started to drop out.
On the other hand, I have a 'low voltage' light (big flashing
yellow) that comes on if the voltage on the bus drops below 13.5
volts, so if the alternator drops out, I get an 'immediate' and hard
to ignore indication to start checking things. Has happened once,
and was able to return to hanger to check out the failed alternator.
I like the light to get your attention -- if installing an ammeter,
still have the light, because most ammeters are small and
inconspicuous and easy to miss on a scan.
Bill Schertz
KIS Cruiser #4045
N343BS
Phase one testing Completed
I am about to start the wiring harness of my Wheeler- and I plan to
include
more instrumentation than my certified plane had. But selectively
more. I took apart the Viking partly to re-use some of the parts,
avionics, etc. part to see exactly what I had paid those IAs to do
over the years that I legally couldn't do. I was surprised at what I
found- wires that had insulation missing due to cracking off and age,
cables that were over half worn, pulley wheels that the bushings
had fallen completely out of, and the list goes on. I all but gave
away my Continental IO 520 because I couldn't economically overhaul
it because of 2 ADs, but I could repair it and fly it after removing
a tablespoon of metal from the oil. No thanks.
After owning the Viking for almost 3 years and 250 hours of flying, the
inadequacy of the electrical system and the engine monitoring system
were the 2 biggest headaches for me. With that knowledge, my Wheeler
will be constructed to include some of the certified requirements,
and some that are OK in experimental but not OK in Certified.
I have mechanical oil pressure, oil temp and water temp gauges. I
will also have an electronic data logging system that I can review
on the ground. The data logging system will record engine parameters,
as well as G loads, acceleration, atmospheric pressures, temps,
etc. That part is easy. Part of this system will be an LED like my
truck has- it says CHECK GAUGES. simple. If something is outside of
the limits, I get a light and it tells me to look at the panel. I
much prefer this to the alternative of suddenly seeing steam and
then all of the coolant is gone, or my alternator quit an hour ago
and now my engine dies from no spark or electronic ignition.
Normally, alternator failure wont kill the engine, but add a dead
battery and it will in our case. So, knowing that the alternator
just went on vacation is a flight safety issue. Likewise,
overheating or oil pressure loss is a show stopper, and I want to
know this ASAP as well.
A warning light that tells us that something bad has happened or is about
to happen is good insurance. A distraction, maybe. But so is losing
an engine on final because of a dead battery, or during climbout due
to overheating.
My opinion on the battery issue is this- if your engine is totally
electronic or electric(i.e. no mechanical ignition system) then I would
install a battery that will last for a few hours if the alternator goes
dead. My choice is the AGM Optima batteries that are sold at auto parts
stores- plenty of CCA, good reserve time, and weight of 34 lbs. Non
spillable, and will still make power with a hole in it. For $189.00,
again, cheap insurance.
Kevin Alderman
Kevin,
The mechanical gauge for oil and water temps is OK as they are still sealed
from the process. The mechanical oil pressure is a different kettle of
fish.
If the oil line to the gauge or the bourdon tube in it leaks in flight you
will probably have at best a mess to clean up when you get on the ground.
Us
an electric oil pressure gauge. Just make sure the sensor wire can not
vibrate
and break or wear through. Electrical wiring comes in different grades. The
stuff you buy at the local auto parts store is most likely the cheap stuff.
The better and then the best still has the same copper conductor which
will be
the same diameter for the gauge used. Where it differs is in the insulation
quality and temperature rating. Go for the best quality. It costs more, but
like the Fram ad said years ago: "pay me now or pay me later".
Dale Davies
Thanks Dale.
As I said, I learned a good bit from taking apart my Viking- I am using all
new aircraft wire. Its lighter, and better all around than wire from Home
Depot. And unfortunately more expensive. Fortunately, there isn't a great
deal of it.
As far as the oil pressure- I am doing it like the Viking- there is an AN
fitting through the firewall that the lines connect to- one from inside and
one from outside. The line from the engine is SS braided and terminates at
the FW, and we pick up from that with a piece of 1/8 aluminum tube on the
inside for a solid rigid connection to the gauge. The chance for leakage is
only if the gauge dies. I have good gauges, so I am optimistic that the
gauge will be OK.
Based on my research on experimental crashes, my plane criteria is simple-
1. KISS- Keep It Simple Stupid.
2. Aircraft wire exclusively and solder or crimp with heat shrink tubing at
every connection.
3. All fuel tubing is to be aluminum tubing except for the very few areas
that a flexible connection is needed.
4. All pitot static system lines are aluminum tube, except for the few
areas that a flexible connection is needed.
I have the benefit of a whole plane here that flew for 43 years to use
parts from, and use for reference. I think I have spent half as much time
lately inside and around the Viking trying to learn what not to do as well
as what to do. While I think some things on the Viking were overkill, there
is no disputing what flew for 43 years without many problems.
All suggestions are welcome- I want to fly for a long long time.
Kevin Alderman
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