Today's Message Index:
----------------------
1. 12:17 AM - Re: Something is stealing my electricity (RoyFollman)
2. 03:25 PM - Re: Hacman Gen 3 Mixture Control (captaincooper)
3. 04:51 PM - Re: Is there any reason to have a separate battery and alt switc (budyerly@msn.com)
4. 05:48 PM - Re: Re: Is there any reason to have a separate battery and alt switc (William Daniell)
5. 06:13 PM - Re: Re: Is there any reason to have a separate battery and alt switc (Gilles Thesee)
6. 06:23 PM - Re: Re: Is there any reason to have a separate battery and alt switc (Gilles Thesee)
7. 07:22 PM - Re: Re: Is there any reason to have a separate battery and alt switc (William Daniell)
8. 11:21 PM - Re: Perspex sliding direct view panels (RoyFollman)
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Subject: | Re: Something is stealing my electricity |
Yeah, your logic is working well, so youre right. I think you should get it fixed
somewhere. Those indicators are not supposed to be like that. Something is
clearly going wrong. Ive had a similar problem, but I got it quickly fixed with
the help from the guys at Ongill Electric (https://ongill.com/). I recommend
you take it to a place like that, where professionals can repair it and you wont
have to pay much. Or just change it, maybe that will be easier to do rather
than looking for a place where to fix it. Good luck with that.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496291#496291
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Subject: | Re: Hacman Gen 3 Mixture Control |
Remi Guerner wrote:
> "if you have any info available which you would be
> prepared to share on your leaning system Remi, I would very much
> appreciate same please. "
>
>
> Hello Kingsley,
> First I want to say that I am not the inventor off the principle of creating
a vacuum in the float bowl using an electric pump to lean the Bing carbs. This
leaning device was designed about 20 years ago by Michel Colomban, designer of
the Cri-Cri and MC100 on which the well known DynAero MCR series were based.
He designed his own pump to create the vacuum. The vacuum is adjusted through
a potentiometer and the mixture ratio is measured using an O2/ lambda probe.
Attached are some original Colomban's drawings (in French, sorry)
> My system uses an electric fuel pump (Pierburg E1F p/n 7.21440.51.0) to create
the vacuum. The vacuum side of the pump is connected to the two carb bowl vents
and the pressure side is connected to the airbox, through a combination of
polyurethane and silicone tubing, nylon tees and straight junctions. See attached
pictures. The vacuum is adjusted using a potentiometer and some electronics
to control the pump voltage. The actual voltage at the pump is being measured
during testing.
> Initial testing showed that the pump was way too powerful and I had to add a
by-pass around it which incorporates a calibrated .8 mm restrictor, to reduce
the effective vacuum. In order to calibrate the system on the bench, I measured
the vacuum using a U shaped clear tubing filled with water. (btw I remember
Colomban saying he was using red wine to better visualize the level). With the
by-pass, the system provides the following vacuum levels: 3 volts at the pump
mm H2O. 4V=30mm, 5.5V=40mm, up to 13V=220mm.
>
> Testing on the aircraft (912ULS + Airmaster prop):
> On the ground (altitude 2000ft): at 2700 RPM, progressively increasing the voltage
at the pump, RPM increases and when reaching 4 volts the RPM peaks at 2900,
then goes down and starts to run rough above 4V.
> at 4000 RPM, progressively increasing the voltage, when reaching 4 volts the
RPM decreases and engine starts to run rough.
> In flight at 10000ft, full throttle, 5000 RPM, propeller in Manual mode to freeze
the pitch, when reaching 4 volts the RPM decreases to 4900 and engine starts
to run rough.
>
> Interpretation of the results: the vacuum necessary to lean the mixture on a
Rotax 912ULS at 10000ft is 30mm H2O approx.
> Leaning on the ground at high idle increases the power, which means the idle
mixture was way too rich.
> Leaning at 10000ft does not increases the power at all. That means that, without
leaning, the mixture is not rich enough to prevent the engine to deliver full
power as it is with legacy aircraft engines. I suppose leaning would slightly
reduce fuel flow of the Rotax at this altitude but I had no means of measuring
the gain accurately and also no means of being sure I was not damaging the
engine. That is why I stopped the experiment at this point.
> Concerns regarding the pump: it is designed to pump fuel not air. In normal use
I suppose the fuel cools and lubricates the pump. Pumping air, even at reduced
voltage, the pump could be damaged. An alternative would be to use a ventilator.
I found some ventilators which are able to provide the required static
vacuum but I think there is a risk of overheating because there would be used
at zero flow, which is not what there are designed for. Some endurance testing
would be required to find out.
>
> Compared to the Hacman, the electric leaning system has a few advantages: there
is no modification of the carbs. It is fail safe: if the pump stops working
your are back to the normal configuration where Carb bowl pressure equals air
box pressure. In case of a problem, just switch it off.
>
> Now why is the high altitude behaviour of the Rotax so different from the legacy
aircraft engines? On Lycoming and Continental engines carburettors there is
a power enrichment device (improperly called "economizer" by Marvel Schebler)
which provides a lot richer mixture when the throttle nears the full forward
position. This is necessary to better cool the cylinders heads to prevent detonation
at full sea level power. At 10000ft, full throttle will give only about
55-65% power, depending on the prop, so the power enrichment is not necessary
anymore. Then the power enrichment and the effect of air density combine to
provide an extremely overrich mixture. At full rich at 10000ft, those engines
will run rough and the spark plugs may foul if you do not lean. When leaning appropriately,
you will see a very significant increase of power.
>
> On the 912 and 912S, the figures provided by ROTAX in the Owner Manual show that
the specific fuel consumption at full sea level power is the same as at cruise
power. So obviously there is no power enrichment system. (there is one on
the 914 but that is another story). The Rotax water cooled cylinder heads temp
are a lot lower than those of the air cooled legacy engines and that makes
detonation a lot less likely, therefore a richer mixture at full throttle is unnecessary.
So at 10000 ft ,the 912 is running slightly too rich due to the reduced
density but not to the point of limiting the available power. Flying at
16000 ft over the top of the Mont Blanc, the Rotax runs flawlessly. An appropriate
leaning device would for sure provide some fuel saving at high altitude
but more testing would be necessary to find out how much.
>
> The attached photos show the pump installed on top of the starboard foot well,
the connection to the carbs and airbox (blue and black tubing), the by-pass
(blue tubing connected to two tees), the controller and voltmeter on the passenger
seat.
> Remi
Im very interested in your tests. Im thinking of installing a vacuum pump to achieve
same results. Im not sure what 30mm H20 is in psi?
--------
Coop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496296#496296
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Subject: | Re: Is there any reason to have a separate battery and alt |
switc
Will and other builders,
It seems like the department of redundant redundancy to have a separate alternator
and master switch. For many it is a matter of "That's the way we've always
done it!" .
The Rotax manual actually implies a switch breaker not just a fuse/circuit breaker
(aka Off Load Fuse Switch). The Europa manual shows a switch or solenoid
of course as does Bob Knuckles in Aeroelectric Connections (aircraft electrical
bible).
Rational for a Rotax: In the event of a battery problem, the battery has a switch
we use to control power to and from the alternator and bus via a master contactor
"kerchunk" solenoid or relay. Others have used a manual marine battery
switch or as I call them "Igor Switches" which can be very heavy. Batteries
normally do not give problems today, but if overcharged, they can. If a cell
shorts, one may detect nasty odors, high amps, and isolating the battery helps
shorten the problem by isolating the battery from the charging and aircraft
bus system. In the event of a imminent crash landing, one should consider isolating
the battery from the electrical system and cockpit as a spark prevention
measure since we occupy the same space as the fuel tank.
The Alternator system has had a switch for three reasons in my opinion. To eliminate
the chance of an overcharging alternator which can damage avionics and
over-charge a battery. Or in the event of a battery problem or master solenoid
failure the alternator will still allow electrical power without the battery.
Or the need to disconnect the alternator due to electrical fires/forced landing
situation as above to kill all power. Hence, there is a separate alternator
switch to kill any spark in our fuel filled cockpit from that electrical source
even forward of the firewall. Normally we separate the alternator from the
bus via the C or control voltage bus feed switch or a 30 amp solenoid/relay
controlled by a DC switch.
Why control the C or control voltage from the bus through a switch is, if the C
wire is open, the regulator is shut down. Typically most in the US wired the
alternator in this way. I have a 914 so my R,Band C wires go to a relay, on
the firewall controlled by the cockpit alternator switch to simply remove the
alternator power from the charge circuit on the firewall. (The alternator output
goes through the firewall plug to the 914 Aux Boost Pump in the panel still,
so I can't really kill all power in the panel. UGH!) In the event of a runaway
Ducati regulator, a C wire of higher voltage from the bus, signals the regulator
to decrease the voltage normally. Although highly unlikely in a B&C type
alternator this can happen (but I haven't seen it ever). Kill the C voltage
and you kill the faulty regulator output if the regulator is working. That
said, Duati regulators don't tend to over volt and a crowbar or any type of over
volt protection is not necessary either. However, if using a power management
system for your bus, the bus will never run at full alternator output voltage
going to the bus, therefore, a C wire off one of these PTC controlled bus
outputs will input a C voltage that is lower (nominally a half a volt) than the
actual output from the regulator and the regulator will be forced to charge
at a higher rate. Not bad for a LiFe type battery or even some AGM types, but
could be harder on the poor Ducati in my opinion. In a low amp draw aircraft
a little overcharge (14.5 volts) helps some of the AGM and LiFe batteries charge
better. (Note, supposedly there are two instances of the Schicke GR6 with
LiFe has had a steady "voltage creep" issue in the Remos and Pipistrel climbing
to 15 volts, but not the Ducati). Today's avionics can take up to 30 volts
without worry, it's the battery that normally can't. So I'm not a fan of crowbars
or experimenting with alternators without switch protection and extensive
testing. Another topic of contention we won't go to.
With a 914, wired via the Rotax manual, one can isolate the battery in the event
of a short or smoking panel and with the battery off, the alternator will supply
power through the aux boost pump switch preventing a flame out. For those
with the 912 series, this is not a problem.
The Ducati type voltage regulator normally fails in a safe mode (dead) preventing
a potential sparking mess on your firewall from the AC current being supplied
by the engine stator. So very safe from runaway problems.
For a simple 912 with the battery located forward of the firewall, in a protective
battery box, AND the regulator is wired to the same contactor as the alternator
output (R,B and C connected together) the system would be safe for most
automotive thinking types. One switch, ON or OFF forward of the firewall like
a auto. This system is car like as you in the cockpit have no control over the
electrical system. It is either ON or OFF. Backup batteries in avionics keep
power alive so one must plan how to shut that off quickly in an emergency
also. Another topic we won't go in to.
Normally a split master switch from suppliers has tabs to make the two switches
work in unison. Those of us who are control freaks, cut these tabs and create
a true split master/alternator.
My vote is do a split master in any aircraft so one has modest control over the
electrical system. Especially if the battery is in the baggage bay or essential
power is necessary in the event of a master contactor failure or battery issue.
I can run both battery and alternator or one or the other to isolate a
problem in foreseeable emergencies.
Best Regards,
Bud Yerly
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496297#496297
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Subject: | Re: Is there any reason to have a separate battery and |
alt switc
Thanks for your wisdom Bud
(Hope youre well)
I was under the impression that you weren't supposed to run the alt without
batt although it is ok to run the bat without the alt. Is this incorrect?
Will
William Daniell
+1 786 878 0246
On Tue, May 12, 2020, 19:55 budyerly@msn.com <budyerly@msn.com> wrote:
>
> Will and other builders,
> It seems like the department of redundant redundancy to have a separate
> alternator and master switch. For many it is a matter of "That's the way
> we've always done it!" .
>
> The Rotax manual actually implies a switch breaker not just a fuse/circuit
> breaker (aka Off Load Fuse Switch). The Europa manual shows a switch or
> solenoid of course as does Bob Knuckles in Aeroelectric Connections
> (aircraft electrical bible).
>
> Rational for a Rotax: In the event of a battery problem, the battery has
> a switch we use to control power to and from the alternator and bus via a
> master contactor "kerchunk" solenoid or relay. Others have used a manual
> marine battery switch or as I call them "Igor Switches" which can be very
> heavy. Batteries normally do not give problems today, but if overcharged,
> they can. If a cell shorts, one may detect nasty odors, high amps, and
> isolating the battery helps shorten the problem by isolating the battery
> from the charging and aircraft bus system. In the event of a imminent
> crash landing, one should consider isolating the battery from the
> electrical system and cockpit as a spark prevention measure since we occupy
> the same space as the fuel tank.
>
> The Alternator system has had a switch for three reasons in my opinion.
> To eliminate the chance of an overcharging alternator which can damage
> avionics and over-charge a battery. Or in the event of a battery problem
> or master solenoid failure the alternator will still allow electrical power
> without the battery. Or the need to disconnect the alternator due to
> electrical fires/forced landing situation as above to kill all power.
> Hence, there is a separate alternator switch to kill any spark in our fuel
> filled cockpit from that electrical source even forward of the firewall.
> Normally we separate the alternator from the bus via the C or control
> voltage bus feed switch or a 30 amp solenoid/relay controlled by a DC
> switch.
>
> Why control the C or control voltage from the bus through a switch is, if
> the C wire is open, the regulator is shut down. Typically most in the US
> wired the alternator in this way. I have a 914 so my R,Band C wires go to
> a relay, on the firewall controlled by the cockpit alternator switch to
> simply remove the alternator power from the charge circuit on the firewall.
> (The alternator output goes through the firewall plug to the 914 Aux Boost
> Pump in the panel still, so I can't really kill all power in the panel.
> UGH!) In the event of a runaway Ducati regulator, a C wire of higher
> voltage from the bus, signals the regulator to decrease the voltage
> normally. Although highly unlikely in a B&C type alternator this can
> happen (but I haven't seen it ever). Kill the C voltage and you kill the
> faulty regulator output if the regulator is working. That said, Duati
> regulators don't tend to over volt and a crowbar or any type of over volt
> protection is not necessary either. However!
> , if using a power management system for your bus, the bus will never run
> at full alternator output voltage going to the bus, therefore, a C wire off
> one of these PTC controlled bus outputs will input a C voltage that is
> lower (nominally a half a volt) than the actual output from the regulator
> and the regulator will be forced to charge at a higher rate. Not bad for a
> LiFe type battery or even some AGM types, but could be harder on the poor
> Ducati in my opinion. In a low amp draw aircraft a little overcharge (14.5
> volts) helps some of the AGM and LiFe batteries charge better. (Note,
> supposedly there are two instances of the Schicke GR6 with LiFe has had a
> steady "voltage creep" issue in the Remos and Pipistrel climbing to 15
> volts, but not the Ducati). Today's avionics can take up to 30 volts
> without worry, it's the battery that normally can't. So I'm not a fan of
> crowbars or experimenting with alternators without switch protection and
> extensive testing. Another topic o!
> f contention we won't go to.
>
> With a 914, wired via the Rotax manual, one can isolate the battery in the
> event of a short or smoking panel and with the battery off, the alternator
> will supply power through the aux boost pump switch preventing a flame
> out. For those with the 912 series, this is not a problem.
>
> The Ducati type voltage regulator normally fails in a safe mode (dead)
> preventing a potential sparking mess on your firewall from the AC current
> being supplied by the engine stator. So very safe from runaway problems.
>
> For a simple 912 with the battery located forward of the firewall, in a
> protective battery box, AND the regulator is wired to the same contactor as
> the alternator output (R,B and C connected together) the system would be
> safe for most automotive thinking types. One switch, ON or OFF forward of
> the firewall like a auto. This system is car like as you in the cockpit
> have no control over the electrical system. It is either ON or OFF.
> Backup batteries in avionics keep power alive so one must plan how to shut
> that off quickly in an emergency also. Another topic we won't go in to.
>
> Normally a split master switch from suppliers has tabs to make the two
> switches work in unison. Those of us who are control freaks, cut these
> tabs and create a true split master/alternator.
>
> My vote is do a split master in any aircraft so one has modest control
> over the electrical system. Especially if the battery is in the baggage
> bay or essential power is necessary in the event of a master contactor
> failure or battery issue. I can run both battery and alternator or one or
> the other to isolate a problem in foreseeable emergencies.
>
> Best Regards,
> Bud Yerly
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=496297#496297
>
>
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Subject: | Re: Is there any reason to have a separate battery and |
alt switc
Le 13/05/2020 01:48, budyerly@msn.com a crit:
> That said, Duati regulators don't tend to over volt and a crowbar or any type
of over volt protection is not necessary either.
[...]
>
> The Ducati type voltage regulator normally fails in a safe mode (dead) preventing
a potential sparking mess....
>
>
Bud and all,
Not to interfere, but I'm taking the liberty of asking whether actually
real data do exist to support the above statements. Or are they just
opinions ?
What if a regulator "fails abnormally", or a sense or control wire gets
severed ? The alternator voltage can climb to 100V peak in millseconds
if something goes wrong.
As in the past some builders reported different modes of failures for
their Ducati voltage regulator, I was wondering...
An overvoltage protection is no big deal, I would advise to better play
safe.
BTW, just in case; some electro wizard homebuilders here might find
information on the Rotax/Ducati alternator here :
http://contrails.free.fr/elec_alt_rotax_en.php
Our study of the Rotax/Ducati voltage regulator will soon be fully
translated.
Any hard data to complement these webpages will be warmly welcomed.
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
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Subject: | Re: Is there any reason to have a separate battery and |
alt switc
Le 13/05/2020 02:46, William Daniell a crit:
>
> /I was under the impression that you weren't supposed to run the alt
> without batt although it is ok to run the bat without the alt. Is
> this incorrect?/
Will,
Your impression is correct.
Some people say that the famous "Rotax" capacitor could replace the
battery, but during our experiments on the voltage regulator, we found
that in certain cases, it would not start - or continue - supplying
power without having first a battery connected.
So with an electrically dependent engine, the Rotax suggested circuit is
to be taken with a grain of salt.
I'll translate the detailed study within the next few weeks.
It would be interesting to ask those questions on the Aeroelectric List,
where we meet builders of many horizons interested - and some very
knowledgeable - in electricity.
FWIW,
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
Message 7
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Subject: | Re: Is there any reason to have a separate battery and |
alt switc
Giles
Thank you.
So i will follow the z16 recommendation having a switch for off , bat and
alt-bat.
Fortunately my 912 turbo will run at low boost on just the mechanical pump
so i am not electrically dependant.
On another note what is the max possible amps produced by the rotax alt?
Will
William Daniell
+1 786 878 0246
On Tue, May 12, 2020, 21:26 Gilles Thesee <gilles@elixir-aircraft.com>
wrote:
> Le 13/05/2020 =C3- 02:46, William Daniell a =C3=A9crit :
>
>
> *I was under the impression that you weren't supposed to run the alt
> without batt although it is ok to run the bat without the alt. Is this
> incorrect?*
>
>
> Will,
>
> Your impression is correct.
> Some people say that the famous "Rotax" capacitor could replace the
> battery, but during our experiments on the voltage regulator, we found th
at
> in certain cases, it would not start - or continue - supplying power
> without having first a battery connected.
> So with an electrically dependent engine, the Rotax suggested circuit is
> to be taken with a grain of salt.
>
> I'll translate the detailed study within the next few weeks.
>
> It would be interesting to ask those questions on the Aeroelectric List,
> where we meet builders of many horizons interested - and some very
> knowledgeable - in electricity.
>
> FWIW,
>
> --
> Best regards,
> Gilles
> http://contrails.free.fr
> http://lapierre.skunkworks.free.fr
>
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Subject: | Re: Perspex sliding direct view panels |
Yeah, your logic is working well, so youre right. I think you should get it fixed
somewhere. Those indicators are not supposed to be like that. Something is
clearly going wrong. Ive had a similar problem, but I got it quickly fixed with
the help from the guys at Ongill Electric (https://ongill.com/). I recommend
you take it to a place like that, where professionals can repair it and you wont
have to pay much. Or just change it, maybe that will be easier to do rather
than looking for a place where to fix it. Good luck with that.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496305#496305
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