Today's Message Index:
----------------------
1. 04:42 AM - Re: Rotax 912 UL alternator drop-out (Damien Graham)
2. 05:33 AM - Re: Rotax 912 UL alternator drop-out (FLYaDIVE)
3. 05:45 AM - Re: 914 Alternator Options (h&jeuropa)
4. 07:07 AM - Re: Rotax 912 UL alternator drop-out (Roger Lee)
5. 08:13 AM - Re: Re: 914 Alternator Options (rparigor@suffolk.lib.ny.us)
6. 12:47 PM - Re: 914 Alternator Options (h&jeuropa)
7. 01:56 PM - Re: Re: 914 Alternator Options (rparigor@suffolk.lib.ny.us)
8. 02:08 PM - Re: Rotax 912 UL alternator drop-out (Richard Girard)
9. 02:58 PM - Rotax part 966726 ignition modules (Richard Girard)
10. 06:04 PM - Re: Rotax 912 UL alternator drop-out (John Cox)
Message 1
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| Subject: | Re: Rotax 912 UL alternator drop-out |
Hey, read this.
Regards,
Damien
Sent from my iPad
On Aug 9, 2013, at 12:42 AM, Paul Kuntz <paul.r.kuntz@gmail.com> wrote:
> I have a homebuilt Pipistrel Sinus with a Rotax 912 UL that I flew to Oshk
osh and back last week. The panel has a dual Dynon Skyview display with two-
axis autopilot, plus radio and transponder. The total electrical load with e
verything running is 7 to 8 amps. Occasionally it can go to 10 amps if I'm c
harging cell phone and iPad en route. I'm pretty confident that I have the e
lectrical system wired so that the ammeter is measuring the total electrical
load.
>
> The alternator dropped out once on the outbound trip, but came back after r
emoving the iPad charging load. The symptom was a voltage drop from 13.8 vo
lts to 12.5 volts. On preflight the voltage may read that high for a minute
or so on a freshly-charged battery, but it quickly drops to 12.2 or 12.1 vo
lts. In flight, the voltage would drop to 12.5 volts and stay there for sev
eral minutes. I would think that if the alternator had failed, I'd see the v
oltage drop to the same 12.1 volts that I see on preflight, and keep droppin
g slowly. I can't see why it would drop to 12.5 volts and stay there, unles
s the voltage regulator is failing in a way that I'm not familiar with.
>
> The alternator dropped out (same symptoms) a few times on the trip back, b
ut by reducing the load to 3 amps (one Skyview display, radio and transponde
r), it stayed on line except for awhile when it seemed that the mid-day sun s
hining on the dashboard was adding extra heat behind the panel. That time w
e brought it back by directing cool air from a fresh air vent forward toward
the spot where the voltage regulator is mounted inside the cabin on the bac
k side of the firewall.
>
> So the problem seems to be heat-related. Does this make sense? The Rotax
alternator is supposed to be rated for 18 amps, and able to handle a steady
load of 14 amps easily. Does the Ducati regulator have a thermal self-prot
ect cutout? Do I perhaps have a regulator that is ready to fail completely,
or should I just put an avionics cooling fan behind the panel to get the ai
r moving?Any other ideas?
>
> Regards,
> Paul Kuntz
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
>
Message 2
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| Subject: | Re: Rotax 912 UL alternator drop-out |
Hi Paul:
Sounds like you have a gorgeous plane.
For a standard and 99.976% of the different types of batteries to charge
you MUST keep the charge voltage between 13.8 to 14.2 VDC. Over 14.2 you
start to overheat the battery. Under 13.8 the voltage is not there to
remove the oxides for the battery plates.
One thing you mentioned perked my ears up - Dual axis autopilot... Now,
that is probably the highest single current draw in your plane. Were you
in A/P? Did you hit and air bumps? When an A/P has to recover from an air
pump the instantaneous current draw goes up sharply. The power is or
should be drawn from the battery followed by the replenishment by the
charging system. Now, from my reading Rotax has the worst charging system
next to Banlon sock rubbing on a wool carpet. But, I would check things
such as you mentioned - COOLING - It may be easier to install a small air
scoop with a hose or fans (caution- fans have their own current draw) to
blow air directly onto the ACU. This is done in quite a few planes where
forced air is blown directly onto the radio stack. The other thing I would
check is wire gauge size. First off it should be 'Teflon' wire and it is
always better to go UP in size. IF the alternator output is rated at 18
Amps the wire size should be no smaller than a 10 AWG and I would use 8
AWG. This is one case where bigger is better. And weight for such a short
run is not an issue. That takes care of the charging requirements. You
will have to address the wire sizes for the other electronic equipment.
Keep in mind Teflon wires allow you to use smaller gauge sizes. But,
HEAT, forces you to use larger gauge sizes.
>From my Rotax readings - I would say Rotax is not supplying the advertized
18 Amps and it is not in a smooth DC waveform output.
Power Reduction Sequence:
Least needed First -
Cell Phone ;-)
iPad ;-)
LIGHTS
A/P
Second Comm Radio
Second Nav/GPS
The only reasion I mention this is because an IPad under charge would be
only about 1 Amp for a dead battery. A cell phone under charge - 0.1 Amp
(100 mA). The other items sure can have high draw.
Another thought - How warm/hot is the firewall? IF the firewall is
warm/hot or if there is dead air under the dash, you may benefit by placing
the ACU on stanchions or placing it on a heat sink. A TRICK that I did on
my plane: I covered the glareshield with black speaker carpet. This
created a heat shield for radio stack by creating a low heat
transfer barrier, aluminum and thin leatherette passes the sun's rays/heat
very easily. It also added some class to the plane.
Good luck,
*Barry*
On Fri, Aug 9, 2013 at 12:42 AM, Paul Kuntz <paul.r.kuntz@gmail.com> wrote:
> I have a homebuilt Pipistrel Sinus with a Rotax 912 UL that I flew to
> Oshkosh and back last week. The panel has a dual Dynon Skyview display with
> two-axis autopilot, plus radio and transponder. The total electrical load
> with everything running is 7 to 8 amps. Occasionally it can go to 10 amps
> if I'm charging cell phone and iPad en route. I'm pretty confident that I
> have the electrical system wired so that the ammeter is measuring the total
> electrical load.
>
> The alternator dropped out once on the outbound trip, but came back after
> removing the iPad charging load. The symptom was a voltage drop from 13.8
> volts to 12.5 volts. On preflight the voltage may read that high for a
> minute or so on a freshly-charged battery, but it quickly drops to 12.2 or
> 12.1 volts. In flight, the voltage would drop to 12.5 volts and stay there
> for several minutes. I would think that if the alternator had failed, I'd
> see the voltage drop to the same 12.1 volts that I see on preflight, and
> keep dropping slowly. I can't see why it would drop to 12.5 volts and stay
> there, unless the voltage regulator is failing in a way that I'm not
> familiar with.
>
> The alternator dropped out (same symptoms) a few times on the trip back,
> but by reducing the load to 3 amps (one Skyview display, radio and
> transponder), it stayed on line except for awhile when it seemed that the
> mid-day sun shining on the dashboard was adding extra heat behind the
> panel. That time we brought it back by directing cool air from a fresh air
> vent forward toward the spot where the voltage regulator is mounted inside
> the cabin on the back side of the firewall.
>
> So the problem seems to be heat-related. Does this make sense? The Rotax
> alternator is supposed to be rated for 18 amps, and able to handle a steady
> load of 14 amps easily. Does the Ducati regulator have a thermal
> self-protect cutout? Do I perhaps have a regulator that is ready to fail
> completely, or should I just put an avionics cooling fan behind the panel
> to get the air moving?Any other ideas?
>
> Regards,
> Paul Kuntz
>
> *
>
> *
>
>
Message 3
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| Subject: | Re: 914 Alternator Options |
Jerry
Our 914 Europa has dual GRT EFIS, GRT EIS, GNS430, GMA340 & GTX327. Also AeroLED
pos & strobes. 914 so TCU & fuel pumps. Typically we see about 8-10 amps
load. The Rotax alt handles this with ease. There is a simple mod for the Ducatti
regulator to address it's potential failure but if you make sure it is cool,
it works fine at 10 amps.
We originally had a B&C 60 amp alt driven off the rear of the engine. There is
a photo earlier in this thread. The coupling failed after 250 hours and we decided
to try just the Rotax alt. So far another 250 hours and no problems.
We did replace the original Whelan lights with AeroLED when we swapped. The Whelans
draw a lot of current.
I'd suggest try just the Rotax alt. You can always add a B&C pad mount.
If you take off the blanking plate you may discover you have a vac pump drive already.
If not, it is easy to add, only requires removal of the gearbox. Lockwood
shows a retrofit package for $750. You can do it yourself or send out the
gearbox.
Hope this helps.
Jim Butcher
N241BW
475 hours and loving it!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=406298#406298
Message 4
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| Subject: | Re: Rotax 912 UL alternator drop-out |
Your system can handle 16 amp continuous load. With this jumping around like this
my first pick for the problem is a poor ground. Most of the time on the LSA
I work on I find loose grounds. They may be hand tight, but wrench loose. Put
a wrench on all your grounds. I have found that this solves 80% of the electrical
issues on LSA especially where composite aircraft are concerned. Depending
on where you live corrosion can be a factor too. You may want to do a real time
amp check too. It is possible you may be pulling a little too much. Also check
for a loose wire on a connection. It may be ready to pull out or hanging
by a strand.
Rotax advertises 20A, but max is 18 intermittent and continuous is 16 amps.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center - Heavy Maint. Rated
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=406311#406311
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| Subject: | Re: 914 Alternator Options |
Hi Jim
"There is a simple mod for the Ducatti regulator to address it's
potential failure"
Can you provide any more information on this mod?
Thx.
Ron Parigoris
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| Subject: | Re: 914 Alternator Options |
Ron,
Supposedly the failure occurs when the regulator gets hot. If you look at a schematic
of the regulator, it is a bridge rectifier with two SCR and two diodes.
Supposedly, the diodes are poorly mounted from a thermal point of view and
that is what fails. The solution is to put two external diodes in parallel with
the originals. This can be done by connecting them between the yellow wires
and R. I'm away from my data but I found a bridge to do this. A bridge is
better than diodes because it provides a mounting surface that is not at R voltage.
I have not incorporated this but have the parts and will do this Fall.
I can email you the PN of the bridge later if you wish.
Jim
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=406365#406365
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| Subject: | Re: 914 Alternator Options |
Hi Jim
Yes please E-Mail info.
I plan on adding a diode in series with the sense wire to raise the
voltage of the regulator. 14.2 to 14.4 is what Odyssey is happy seeing,
Ducati is set way low.
Ron P.
"h&jeuropa"
> <butcher43@att.net>
>
> Ron,
>
> Supposedly the failure occurs when the regulator gets hot. If you
look at
> a schematic of the regulator, it is a bridge rectifier with two SCR
and
> two diodes. Supposedly, the diodes are poorly mounted from a
thermal
> point of view and that is what fails. The solution is to put two
external
> diodes in parallel with the originals. This can be done by
connecting
> them between the yellow wires and R. I'm away from my data but I
found a
> bridge to do this. A bridge is better than diodes because it
provides a
> mounting surface that is not at R voltage.
>
> I have not incorporated this but have the parts and will do this
Fall.
>
> I can email you the PN of the bridge later if you wish.
>
> Jim
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=406365#406365
>
>
>
>
>
>
>
>
>
>
>
Message 8
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| Subject: | Re: Rotax 912 UL alternator drop-out |
Barry, Teflon may be a wonder product and a by product of the Manhattan
Program to develop the "Bomb", but it will not carry electricity. I have a
block in the shop that I tested with a VOM. It had infinite resistance and
a power supply connected across it showed zero voltage coming through the
block.
Perhaps you were referring to the insulation used on COPPER wire? If that
is the case WIRE size is WIRE size and the ability of the WIRE to allow
electrons to do what they do, flow, cloud, or kill Schroedinger's cat, does
not depend one whit on the insulation on the WIRE. The gage of WIRE is what
determines its ability to handle amperage. Too much amperage passed though
a too small wire makes what is known as a fusible link, perhaps not by
design or intent, but certainly in practice. The insulation may make it
possible to carry slightly more amperage without the INSULATION melting and
the INSULATION type may allow for great weight savings, say Tefzel vs. PVC
but again it's the COPPER WIRE that does the job and there are hundreds of
thousands of aircraft and millions of automobiles that have rubber
encapsulated cotton braid, PVC, Tefzel and other insulations that are
flying and rolling in perfect safety. The important thing is to use the
correct gage of WIRE for the circuit capacity and craft it to eliminate
places that might cause the insulation to be penetrated and short the wire
to ground.
Last, Teflon wire insulation has a problem and that is that it is soft.
Things like nylon ties or even waxed cotton wire lacing will cause it to
extrude out from under the tie and create a short. For that reason alone I
would not recommend its use in an aircraft.
Rick Girard
do not archive
On Fri, Aug 9, 2013 at 7:32 AM, FLYaDIVE <flyadive@gmail.com> wrote:
> Hi Paul:
>
> Sounds like you have a gorgeous plane.
> For a standard and 99.976% of the different types of batteries to charge
> you MUST keep the charge voltage between 13.8 to 14.2 VDC. Over 14.2 you
> start to overheat the battery. Under 13.8 the voltage is not there to
> remove the oxides for the battery plates.
> One thing you mentioned perked my ears up - Dual axis autopilot... Now,
> that is probably the highest single current draw in your plane. Were you
> in A/P? Did you hit and air bumps? When an A/P has to recover from an air
> pump the instantaneous current draw goes up sharply. The power is or
> should be drawn from the battery followed by the replenishment by the
> charging system. Now, from my reading Rotax has the worst charging system
> next to Banlon sock rubbing on a wool carpet. But, I would check things
> such as you mentioned - COOLING - It may be easier to install a small air
> scoop with a hose or fans (caution- fans have their own current draw) to
> blow air directly onto the ACU. This is done in quite a few planes where
> forced air is blown directly onto the radio stack. The other thing I would
> check is wire gauge size. First off it should be 'Teflon' wire and it is
> always better to go UP in size. IF the alternator output is rated at 18
> Amps the wire size should be no smaller than a 10 AWG and I would use 8
> AWG. This is one case where bigger is better. And weight for such a short
> run is not an issue. That takes care of the charging requirements. You
> will have to address the wire sizes for the other electronic equipment.
> Keep in mind Teflon wires allow you to use smaller gauge sizes. But,
> HEAT, forces you to use larger gauge sizes.
> From my Rotax readings - I would say Rotax is not supplying the advertized
> 18 Amps and it is not in a smooth DC waveform output.
> Power Reduction Sequence:
> Least needed First -
> Cell Phone ;-)
> iPad ;-)
> LIGHTS
> A/P
> Second Comm Radio
> Second Nav/GPS
>
> The only reasion I mention this is because an IPad under charge would be
> only about 1 Amp for a dead battery. A cell phone under charge - 0.1 Amp
> (100 mA). The other items sure can have high draw.
>
> Another thought - How warm/hot is the firewall? IF the firewall is
> warm/hot or if there is dead air under the dash, you may benefit by placing
> the ACU on stanchions or placing it on a heat sink. A TRICK that I did on
> my plane: I covered the glareshield with black speaker carpet. This
> created a heat shield for radio stack by creating a low heat
> transfer barrier, aluminum and thin leatherette passes the sun's rays/heat
> very easily. It also added some class to the plane.
>
> Good luck,
>
> *Barry*
> On Fri, Aug 9, 2013 at 12:42 AM, Paul Kuntz <paul.r.kuntz@gmail.com>wrote:
>
>> I have a homebuilt Pipistrel Sinus with a Rotax 912 UL that I flew to
>> Oshkosh and back last week. The panel has a dual Dynon Skyview display with
>> two-axis autopilot, plus radio and transponder. The total electrical load
>> with everything running is 7 to 8 amps. Occasionally it can go to 10 amps
>> if I'm charging cell phone and iPad en route. I'm pretty confident that I
>> have the electrical system wired so that the ammeter is measuring the total
>> electrical load.
>>
>> The alternator dropped out once on the outbound trip, but came back after
>> removing the iPad charging load. The symptom was a voltage drop from 13.8
>> volts to 12.5 volts. On preflight the voltage may read that high for a
>> minute or so on a freshly-charged battery, but it quickly drops to 12.2 or
>> 12.1 volts. In flight, the voltage would drop to 12.5 volts and stay there
>> for several minutes. I would think that if the alternator had failed, I'd
>> see the voltage drop to the same 12.1 volts that I see on preflight, and
>> keep dropping slowly. I can't see why it would drop to 12.5 volts and stay
>> there, unless the voltage regulator is failing in a way that I'm not
>> familiar with.
>>
>> The alternator dropped out (same symptoms) a few times on the trip back,
>> but by reducing the load to 3 amps (one Skyview display, radio and
>> transponder), it stayed on line except for awhile when it seemed that the
>> mid-day sun shining on the dashboard was adding extra heat behind the
>> panel. That time we brought it back by directing cool air from a fresh air
>> vent forward toward the spot where the voltage regulator is mounted inside
>> the cabin on the back side of the firewall.
>>
>> So the problem seems to be heat-related. Does this make sense? The
>> Rotax alternator is supposed to be rated for 18 amps, and able to handle a
>> steady load of 14 amps easily. Does the Ducati regulator have a thermal
>> self-protect cutout? Do I perhaps have a regulator that is ready to fail
>> completely, or should I just put an avionics cooling fan behind the panel
>> to get the air moving?Any other ideas?
>>
>> Regards,
>> Paul Kuntz
>>
>> *
>>
>> ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List
>> tp://forums.matronics.com
>> _blank">http://www.matronics.com/contribution
>> *
>>
>>
> *
>
> *
>
>
--
Zulu Delta
Mk IIIC
Thanks, Homer GBYM
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- Groucho Marx
Message 9
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| Subject: | Rotax part 966726 ignition modules |
I recently had a hair-puller-outer problem with a 912 ULS that would not
start.
Since both carbs leaked fuel out the overflow tubes and they had not been
rebuilt ever, I did that. In studying the aircraft's fuel system and
studying the Rotax manual I found the fuel system had no return line.
Having not crafted a fuel system for a 912 before, and finding the
schematic in the IPC clear as mud, I contacted Roger Lee off list for some
advice. Like many on this list I've learned a lot from Roger and having him
take the time, while on vacation mind you, to give me the part numbers to
order is a testimony to his character, but that's an aside to this story.
All plumbed up, no joy on getting the engine to fire. Did all the
diagnostics and it boiled down to the ignition modules.
Fortunately, there is a message on the Rotax.com forum about ignition
modules that would not fire below a certain rpm and advised sending them to
Lockwood to be tested. Last Monday I called Lockwood, they emailed a work
order and I forwarded it to my customer so he could mail them out for
testing.
In talking to Aaron, he said this was a known problem. Some 966726 modules
go south and will not fire until some elevated rpm not reachable with a
starter. With their test system Lockwood can spin them up and determine the
point where firing begins. They have found that once they do fire, the
modules sometimes return to the correct firing rpm for awhile but when
allowed to set for a day or two will redevelop the defect.
Bottom line of this missive is that if you have a problem with engine
starting and you have done all the trouble shooting to make sure that an
ignition is not inadvertently grounded out at the switch or the wiring, it
may be worth your time to send them to Lockwood for testing.
I don't know if L.E.A.F. or CPS can do this test, the fellow who sent the
message used Lockwood so I did too.
There's an upside to this story. The new modules, p/n 966727 have the
capabilities of the 'Soft Start Module" built in. Rotax, aware of the
problem with the old moduels has a special price for the new modules, $913,
that is less than half the cost of the old modules and if you order them
from Lockwood they waive the cost of testing the old modules so you save a
further $50, too.
Rick Girard
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- Groucho Marx
Message 10
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| Subject: | Re: Rotax 912 UL alternator drop-out |
Richard, I enjoyed reading your above post but I would also love to hear a
reference to support your position on plastic zip ties and waxed cord. I
am an EAA Tech Advisor and A/P with I/A for a major airline along with
being ROTAX trained. Those products are used throughout the aircraft I
service. I make my livelihood dealing as an Avionics Tech chasing Chafes,
Shorts, Opens and errant electrons. I am always open for refreshing
ideals. Flush cut wire cutters, wire spoons, a strong light source might
also be on your hit list. What do you recommend?
I do support the position that zip ties should not be used on engine mounts
but that subject digresses from Tefzel Mil-Spec wire and your presentation
that zip ties and cordage should not be used. We use black coated cordage
aft of the firewall and white coated cordage within the higher heat regimes
of forward of the firewall. Chafing, routing and security of wires is an
important build skill.
I look forward to the reference that drove your conclusion.
John Cox
On Fri, Aug 9, 2013 at 2:08 PM, Richard Girard <aslsa.rng@gmail.com> wrote:
> Barry, Teflon may be a wonder product and a by product of the Manhattan
> Program to develop the "Bomb", but it will not carry electricity. I have a
> block in the shop that I tested with a VOM. It had infinite resistance and
> a power supply connected across it showed zero voltage coming through the
> block.
> Perhaps you were referring to the insulation used on COPPER wire? If that
> is the case WIRE size is WIRE size and the ability of the WIRE to allow
> electrons to do what they do, flow, cloud, or kill Schroedinger's cat, does
> not depend one whit on the insulation on the WIRE. The gage of WIRE is what
> determines its ability to handle amperage. Too much amperage passed though
> a too small wire makes what is known as a fusible link, perhaps not by
> design or intent, but certainly in practice. The insulation may make it
> possible to carry slightly more amperage without the INSULATION melting and
> the INSULATION type may allow for great weight savings, say Tefzel vs. PVC
> but again it's the COPPER WIRE that does the job and there are hundreds of
> thousands of aircraft and millions of automobiles that have rubber
> encapsulated cotton braid, PVC, Tefzel and other insulations that are
> flying and rolling in perfect safety. The important thing is to use the
> correct gage of WIRE for the circuit capacity and craft it to eliminate
> places that might cause the insulation to be penetrated and short the wire
> to ground.
> Last, Teflon wire insulation has a problem and that is that it is soft.
> Things like nylon ties or even waxed cotton wire lacing will cause it to
> extrude out from under the tie and create a short. For that reason alone I
> would not recommend its use in an aircraft.
>
> Rick Girard
> do not archive
>
>
> On Fri, Aug 9, 2013 at 7:32 AM, FLYaDIVE <flyadive@gmail.com> wrote:
>
>> Hi Paul:
>>
>> Sounds like you have a gorgeous plane.
>> For a standard and 99.976% of the different types of batteries to charge
>> you MUST keep the charge voltage between 13.8 to 14.2 VDC. Over 14.2 you
>> start to overheat the battery. Under 13.8 the voltage is not there to
>> remove the oxides for the battery plates.
>> One thing you mentioned perked my ears up - Dual axis autopilot... Now,
>> that is probably the highest single current draw in your plane. Were you
>> in A/P? Did you hit and air bumps? When an A/P has to recover from an air
>> pump the instantaneous current draw goes up sharply. The power is or
>> should be drawn from the battery followed by the replenishment by the
>> charging system. Now, from my reading Rotax has the worst charging system
>> next to Banlon sock rubbing on a wool carpet. But, I would check things
>> such as you mentioned - COOLING - It may be easier to install a small air
>> scoop with a hose or fans (caution- fans have their own current draw) to
>> blow air directly onto the ACU. This is done in quite a few planes where
>> forced air is blown directly onto the radio stack. The other thing I would
>> check is wire gauge size. First off it should be 'Teflon' wire and it is
>> always better to go UP in size. IF the alternator output is rated at 18
>> Amps the wire size should be no smaller than a 10 AWG and I would use 8
>> AWG. This is one case where bigger is better. And weight for such a short
>> run is not an issue. That takes care of the charging requirements. You
>> will have to address the wire sizes for the other electronic equipment.
>> Keep in mind Teflon wires allow you to use smaller gauge sizes. But,
>> HEAT, forces you to use larger gauge sizes.
>> From my Rotax readings - I would say Rotax is not supplying the
>> advertized 18 Amps and it is not in a smooth DC waveform output.
>> Power Reduction Sequence:
>> Least needed First -
>> Cell Phone ;-)
>> iPad ;-)
>> LIGHTS
>> A/P
>> Second Comm Radio
>> Second Nav/GPS
>>
>> The only reasion I mention this is because an IPad under charge would be
>> only about 1 Amp for a dead battery. A cell phone under charge - 0.1 Amp
>> (100 mA). The other items sure can have high draw.
>>
>> Another thought - How warm/hot is the firewall? IF the firewall is
>> warm/hot or if there is dead air under the dash, you may benefit by placing
>> the ACU on stanchions or placing it on a heat sink. A TRICK that I did on
>> my plane: I covered the glareshield with black speaker carpet. This
>> created a heat shield for radio stack by creating a low heat
>> transfer barrier, aluminum and thin leatherette passes the sun's rays/heat
>> very easily. It also added some class to the plane.
>>
>> Good luck,
>>
>> *Barry*
>> On Fri, Aug 9, 2013 at 12:42 AM, Paul Kuntz <paul.r.kuntz@gmail.com>wrote:
>>
>>> I have a homebuilt Pipistrel Sinus with a Rotax 912 UL that I flew to
>>> Oshkosh and back last week. The panel has a dual Dynon Skyview display with
>>> two-axis autopilot, plus radio and transponder. The total electrical load
>>> with everything running is 7 to 8 amps. Occasionally it can go to 10 amps
>>> if I'm charging cell phone and iPad en route. I'm pretty confident that I
>>> have the electrical system wired so that the ammeter is measuring the total
>>> electrical load.
>>>
>>> The alternator dropped out once on the outbound trip, but came back
>>> after removing the iPad charging load. The symptom was a voltage drop from
>>> 13.8 volts to 12.5 volts. On preflight the voltage may read that high for
>>> a minute or so on a freshly-charged battery, but it quickly drops to 12.2
>>> or 12.1 volts. In flight, the voltage would drop to 12.5 volts and stay
>>> there for several minutes. I would think that if the alternator had
>>> failed, I'd see the voltage drop to the same 12.1 volts that I see on
>>> preflight, and keep dropping slowly. I can't see why it would drop to 12.5
>>> volts and stay there, unless the voltage regulator is failing in a way that
>>> I'm not familiar with.
>>>
>>> The alternator dropped out (same symptoms) a few times on the trip back,
>>> but by reducing the load to 3 amps (one Skyview display, radio and
>>> transponder), it stayed on line except for awhile when it seemed that the
>>> mid-day sun shining on the dashboard was adding extra heat behind the
>>> panel. That time we brought it back by directing cool air from a fresh air
>>> vent forward toward the spot where the voltage regulator is mounted inside
>>> the cabin on the back side of the firewall.
>>>
>>> So the problem seems to be heat-related. Does this make sense? The
>>> Rotax alternator is supposed to be rated for 18 amps, and able to handle a
>>> steady load of 14 amps easily. Does the Ducati regulator have a thermal
>>> self-protect cutout? Do I perhaps have a regulator that is ready to fail
>>> completely, or should I just put an avionics cooling fan behind the panel
>>> to get the air moving?Any other ideas?
>>>
>>> Regards,
>>> Paul Kuntz
>>>
>>> *
>>>
>>> ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List
>>> tp://forums.matronics.com
>>> _blank">http://www.matronics.com/contribution
>>> *
>>>
>>>
>> *
>>
>> ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List
>> tp://forums.matronics.com
>> _blank">http://www.matronics.com/contribution
>> *
>>
>>
>
>
> --
> Zulu Delta
> Mk IIIC
> Thanks, Homer GBYM
>
> It isn't necessary to have relatives in Kansas City in order to be unhappy.
> - Groucho Marx
>
> *
>
> *
>
>
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