Electrical Wiring Continued
The new Rotorway Talon
models have a completely new electrical system and this discussion
does not apply to them.
Below is a photo of the
fuel pump inertia switch bracket that shows where the alternator
wire rubbed and then shorted out. The wire in the photo has been
soldered together and shrink wrap was later applied. Then the
entire wire bundle was re-routed and properly secured- see the
photos below. This short took out all of the components at altitude
and resulted in a full down autorotation for real. This was caused
by the builder improperly routing and protecting his wiring harness
and a potential problem with the overhead wiring if a short circuit
occurs.
If the alternator wire
is allowed to short out the power supply fuses in the overhead
panel can all blow shutting off power to the engine systems.
In the below photo I
was flying with a student when the engine on his Rotorway 162F
quit and the FADEC display went blank. The wire bundle had run
along the frame and when the improperly constructed fuel tank
strap slid down the frame the bracket cut into the alternator
wire and the wire shorted. We were able to auto to the ground
safely with no damage and you can see how the wiring is now properly
supported and stood off the frame while being protected by plastic
spiral wrap.
Look closely at the bottom
of the fuel tank bracket where it is sitting on the frame. You
can see the carbon still there from where it cut into the wiring
harness and shorted out all of the engine support systems causing
a complete engine failure. The photo was taken after we had re-routed
the wires, protected the bundle in spiral wrap, and used soft
plastic hose as stand-off supports.
The photo below I am
holding the wire where the rear Fuel tank bracket cut into the
alternator wire bundle and caused the short.
In the photo below you
can see where we put the fuel tank back into it's proper position
as discussed in the fuel tank strap section of Hints and Tips.
We have also re-routed all wiring away from anything that can
cause a short, protected it with plastic spiral wrap, and made
soft plastic hose stand-offs to support the bundle off the frame.
The photo below shows
how we re-routed the repaired wire bundle and supported it. It
is also protected by plastic spiral wrap. Notice the rubber protector
for the wires as they enter the over head panel box. The sharp
edges of the fiberglass hole will cut right though any unprotected
wiring.
On my own early Rotorway Exec 152 I installed an oil
cooler with a cooling fan and a switch to activate it.
Above the switch is a small green light that indicated
that the fan was on. All indicator lights except the red
warning lights might benefit from being on a dimmer for
night flying. Every switch had it's own circuit breaker.
Notice I even had an alternator warning and oil pressure
warning light, good things to have. Warning lights get
your attention should a failure occur. Your helicopter
might benefit from an ALTERNATOR WARNING
LIGHT. If the alternator fails or the water pump
belt breaks you need the warning to allow sufficient time
to safely reach the ground before the engine quits. If
it illuminates, enter an auto, monitor your engine condition,
and if you have the power, initiate a power recovery at
the bottom of the auto.
I have copied an advertisement for a nice alternator
warning light below.
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The add reads:
"The
Very Best “13 Volt Idiot Light” Since Hector
was a Pup!
US$39.95 This is the cheapest insurance you can buy. Don't
fly without proper warning lights. How much is your ship
and your life worth???
They call these “Idiot Lights”. An “Idiot”
is defined as an epithet that can be directed at anyone
but you. So do this for your friends—they really need
it.
Since your alternator and battery voltage is about 14.5
volts when the alternator is working, a Low Voltage circuit
trips at 13 volts to tell you that your alternator has failed—and
from that point you’re going to be losing electrical
energy—so you’d better start making plans if
you need the electrical power. The FADEC computers cut out
at somewhere over 10 volts so you need a warning indicator
http://www.periheliondesign.com/moreproducts.htm"
This light will also tell you if your water pump/alternator
belt breaks. If it illuminates you can look at both your
voltage gauge and your water temp gauge to determine the
cause as you locate an emergency landing spot on the ground.
If it is a belt break, the water temp will begin to rise
and an emergency descent will be necessary to save your
engine. An alternator warning light is a super investment
and should be on every Rotorway helicopter.
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Note
that the new Rotorway Talon uses an electric water pump
so it no longer requires the water pump belt. |
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If you
want your Helicopter battery to last CLICK
HERE |
If you would like to learn how
to make a simple wire standoff CLICK
HERE |