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kenryan
Joined: 20 Oct 2009
Posts: 426
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 Posted: Wed Oct 05, 2016 11:58 am Post subject: rotax generator without battery |
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I am designing my electrical system for the Rotax 914 which requires two electrical fuel pumps. My plan is to run the main pump (and nothing else) off the generator, and the auxiliary pump off the bus, which will be connected to a battery and the external 40 amp alternator.
According to the Rotax 914 Installation Manual, the minimum idle rpm is 1400, and at 1400 engine rpm the generator produces only 2a/13.5v (+/- 5%). The pumps are Walbro GSL395.
Is there any danger that this might be setting up a problem that would damage either the regulator-rectifier or the fuel pump?
Also, what would be the best way to insure that the auxiliary pump (if activated) would automatically stop in the event of a crash?
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nuckolls.bob(at)aeroelect
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| Posted: Wed Oct 05, 2016 1:07 pm Post subject: rotax generator without battery |
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At 02:54 PM 10/5/2016, you wrote:
| Quote: | I am designing my electrical system for the Rotax 914 which requires two electrical fuel pumps. My plan is to run the main pump (and nothing else) off the generator, and the auxiliary pump off the bus, which will be connected to a battery and the external 40 amp alternator.
According to the Rotax 914 Installation Manual, the minimum idle rpm is 1400, and at 1400 engine rpm the generator produces only 2a/13.5v (+/- 5%). The pumps are Walbro GSL395.
Is there any danger that this might be setting up a problem that would damage either the regulator-rectifier or the fuel pump?
|
No
| Quote: | | Also, what would be the best way to insure that the auxiliary pump (if activated) would automatically stop in the event of a crash? |
This is usually managed with the master switch . . .
Bob . . .
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Wed Oct 05, 2016 1:50 pm Post subject: rotax generator without battery |
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Thanks Bob.Â
What would the effect be on the pump if it was getting less than ideal amps/volts? Would it simply lower the performance of the pump?Â
Regarding automatic shut off of the pump, the master switch is hardly "automatic." The scenario would be one of a crash with injuries. We would want the electric fuel pump to shut down when the engine shuts down so that it does not continue to pump fuel, possibly into a ruptured fuel system.
Ken
On Wed, Oct 5, 2016 at 1:05 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 02:54 PM 10/5/2016, you wrote:
| Quote: | I am designing my electrical system for the Rotax 914 which requires two electrical fuel pumps. My plan is to run the main pump (and nothing else) off the generator, and the auxiliary pump off the bus, which will be connected to a battery and the external 40 amp alternator.
According to the Rotax 914 Installation Manual, the minimum idle rpm is 1400, and at 1400 engine rpm the generator produces only 2a/13.5v (+/- 5%). The pumps are Walbro GSL395.
Is there any danger that this might be setting up a problem that would damage either the regulator-rectifier or the fuel pump?
|
 No
| Quote: | | Also, what would be the best way to insure that the auxiliary pump (if activated) would automatically stop in the event of a crash? |
 This is usually managed with the master switch . . .
 Bob . . .
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alec(at)alecmyers.com
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| Posted: Wed Oct 05, 2016 2:40 pm Post subject: rotax generator without battery |
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There are about a zillion certified aircraft out there with electric fuel pumps that are engaged and energised specifically for takeoff and landing. So you may be trying to solve a problem that isn't judged to arise very often; particularly if you factor in the small but real possibility of whatever automatic fuel pump shutoff mechanism you design engaging at the wrong moment (shortly after takeoff, say) and causing the very accident you are hoping to avoid.
For an expectedly rough landing in the event of a forced approach onto rough terrain, the fuel and electrical systems should all be purged and isolated well in advance of touchdown, as Bob suggests, by use of the master switch and fuel shutoff.
On Oct 5, 2016, at 5:48 PM, Ken Ryan <keninalaska(at)gmail.com (keninalaska(at)gmail.com)> wrote:
| Quote: | Thanks Bob.
What would the effect be on the pump if it was getting less than ideal amps/volts? Would it simply lower the performance of the pump?
Regarding automatic shut off of the pump, the master switch is hardly "automatic." The scenario would be one of a crash with injuries. We would want the electric fuel pump to shut down when the engine shuts down so that it does not continue to pump fuel, possibly into a ruptured fuel system.
Ken
On Wed, Oct 5, 2016 at 1:05 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 02:54 PM 10/5/2016, you wrote:
| Quote: | I am designing my electrical system for the Rotax 914 which requires two electrical fuel pumps. My plan is to run the main pump (and nothing else) off the generator, and the auxiliary pump off the bus, which will be connected to a battery and the external 40 amp alternator.
According to the Rotax 914 Installation Manual, the minimum idle rpm is 1400, and at 1400 engine rpm the generator produces only 2a/13.5v (+/- 5%). The pumps are Walbro GSL395.
Is there any danger that this might be setting up a problem that would damage either the regulator-rectifier or the fuel pump?
|
No
| Quote: | | Also, what would be the best way to insure that the auxiliary pump (if activated) would automatically stop in the event of a crash? |
This is usually managed with the master switch . . .
Bob . . .
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Wed Oct 05, 2016 2:58 pm Post subject: rotax generator without battery |
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That may be true, but the Rotax 912iS and the UL Power engines do shut off fuel pumps when the engine stops as do all modern automobiles. Again, I am not concerned with a forced landing where there is time to prepare. I am concerned with a crash, such as flipping the aircraft due to soft or rough terrain, or a million other things that could conceivably happen (and do happen). In such an instance, I would prefer not to have a high pressure fuel pump doing its job.Â
On Wed, Oct 5, 2016 at 2:35 PM, Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)> wrote:
| Quote: |
There are about a zillion certified aircraft out there with electric fuel pumps that are engaged and energised specifically for takeoff and landing. So you may be trying to solve a problem that isn't judged to arise very often; particularly if you factor in the small but real possibility of whatever automatic fuel pump shutoff mechanism you design engaging at the wrong moment (shortly after takeoff, say) and causing the very accident you are hoping to avoid.
For an expectedly rough landing in the event of a forced approach onto rough terrain, the fuel and electrical systems should all be purged and isolated well in advance of touchdown, as Bob suggests, by use of the master switch and fuel shutoff.
On Oct 5, 2016, at 5:48 PM, Ken Ryan <keninalaska(at)gmail.com (keninalaska(at)gmail.com)> wrote:
| Quote: | Thanks Bob.Â
What would the effect be on the pump if it was getting less than ideal amps/volts? Would it simply lower the performance of the pump?Â
Regarding automatic shut off of the pump, the master switch is hardly "automatic." The scenario would be one of a crash with injuries. We would want the electric fuel pump to shut down when the engine shuts down so that it does not continue to pump fuel, possibly into a ruptured fuel system.
Ken
On Wed, Oct 5, 2016 at 1:05 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 02:54 PM 10/5/2016, you wrote:
| Quote: | I am designing my electrical system for the Rotax 914 which requires two electrical fuel pumps. My plan is to run the main pump (and nothing else) off the generator, and the auxiliary pump off the bus, which will be connected to a battery and the external 40 amp alternator.
According to the Rotax 914 Installation Manual, the minimum idle rpm is 1400, and at 1400 engine rpm the generator produces only 2a/13.5v (+/- 5%). The pumps are Walbro GSL395.
Is there any danger that this might be setting up a problem that would damage either the regulator-rectifier or the fuel pump?
|
 No
| Quote: | | Also, what would be the best way to insure that the auxiliary pump (if activated) would automatically stop in the event of a crash? |
 This is usually managed with the master switch . . .
 Bob . . .
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alec(at)alecmyers.com
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| Posted: Wed Oct 05, 2016 3:13 pm Post subject: rotax generator without battery |
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Perhaps more practice at landing...?
On Oct 5, 2016, at 6:56 PM, Ken Ryan <keninalaska(at)gmail.com (keninalaska(at)gmail.com)> wrote:
| Quote: | That may be true, but the Rotax 912iS and the UL Power engines do shut off fuel pumps when the engine stops as do all modern automobiles. Again, I am not concerned with a forced landing where there is time to prepare. I am concerned with a crash, such as flipping the aircraft due to soft or rough terrain, or a million other things that could conceivably happen (and do happen). In such an instance, I would prefer not to have a high pressure fuel pump doing its job.
On Wed, Oct 5, 2016 at 2:35 PM, Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)> wrote:
| Quote: |
There are about a zillion certified aircraft out there with electric fuel pumps that are engaged and energised specifically for takeoff and landing. So you may be trying to solve a problem that isn't judged to arise very often; particularly if you factor in the small but real possibility of whatever automatic fuel pump shutoff mechanism you design engaging at the wrong moment (shortly after takeoff, say) and causing the very accident you are hoping to avoid.
For an expectedly rough landing in the event of a forced approach onto rough terrain, the fuel and electrical systems should all be purged and isolated well in advance of touchdown, as Bob suggests, by use of the master switch and fuel shutoff.
On Oct 5, 2016, at 5:48 PM, Ken Ryan <keninalaska(at)gmail.com (keninalaska(at)gmail.com)> wrote:
| Quote: | Thanks Bob.
What would the effect be on the pump if it was getting less than ideal amps/volts? Would it simply lower the performance of the pump?
Regarding automatic shut off of the pump, the master switch is hardly "automatic." The scenario would be one of a crash with injuries. We would want the electric fuel pump to shut down when the engine shuts down so that it does not continue to pump fuel, possibly into a ruptured fuel system.
Ken
On Wed, Oct 5, 2016 at 1:05 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 02:54 PM 10/5/2016, you wrote:
| Quote: | I am designing my electrical system for the Rotax 914 which requires two electrical fuel pumps. My plan is to run the main pump (and nothing else) off the generator, and the auxiliary pump off the bus, which will be connected to a battery and the external 40 amp alternator.
According to the Rotax 914 Installation Manual, the minimum idle rpm is 1400, and at 1400 engine rpm the generator produces only 2a/13.5v (+/- 5%). The pumps are Walbro GSL395.
Is there any danger that this might be setting up a problem that would damage either the regulator-rectifier or the fuel pump?
|
No
| Quote: | | Also, what would be the best way to insure that the auxiliary pump (if activated) would automatically stop in the event of a crash? |
This is usually managed with the master switch . . .
Bob . . .
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user9253
Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan
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| Posted: Wed Oct 05, 2016 4:42 pm Post subject: Re: rotax generator without battery |
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How about putting an oil pressure switch in series with the electric fuel pump? And maybe a momentary push button switch in parallel with the oil pressure switch to allow for checking pump operation with the engine not running.
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Wed Oct 05, 2016 5:08 pm Post subject: rotax generator without battery |
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Joe, how would I accomplish the engine start? The primary fuel pump needs the generator and the auxiliary needs oil pressure. Is that what the push button is for?
Sent from my Android. Sorry Steve.
On Oct 5, 2016 4:50 PM, "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)> wrote: | Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
How about putting an oil pressure switch in series with the electric fuel pump? And maybe a momentary push button switch in parallel with the oil pressure switch to allow for checking pump operation with the engine not running.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=460989#460989
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ashleysc(at)broadstripe.n
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| Posted: Wed Oct 05, 2016 5:39 pm Post subject: rotax generator without battery |
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Hi Ken;
Are the crankshaft and alternator pulleys the same size, or is the alternator a spline drive unit? Otherwise, the alternator usually runs faster than the engine.
Cheers! Stu.
From: "Ken Ryan" <keninalaska(at)gmail.com>
To: aeroelectric-list(at)matronics.com
Sent: Wednesday, October 5, 2016 12:54:16 PM
Subject: rotax generator without battery
I am designing my electrical system for the Rotax 914 which requires two electrical fuel pumps. My plan is to run the main pump (and nothing else) off the generator, and the auxiliary pump off the bus, which will be connected to a battery and the external 40 amp alternator.
According to the Rotax 914 Installation Manual, the minimum idle rpm is 1400, and at 1400 engine rpm the generator produces only 2a/13.5v (+/- 5%). The pumps are Walbro GSL395.
Is there any danger that this might be setting up a problem that would damage either the regulator-rectifier or the fuel pump?
Also, what would be the best way to insure that the auxiliary pump (if activated) would automatically stop in the event of a crash?
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gilles.thesee(at)free.fr
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| Posted: Wed Oct 05, 2016 10:12 pm Post subject: rotax generator without battery |
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Le 06/10/2016 à 02:42, user9253 a écrit :
| Quote: | | Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com> (fransew(at)gmail.com)
How about putting an oil pressure switch in series with the electric fuel pump? And maybe a momentary push button switch in parallel with the oil pressure switch to allow for checking pump operation with the engine not running.
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Hi all,
Just a few thoughts
he Rotax 914 uses two electric fuel pumps. If no fuel is pumped into the carbs, the engine stops.
Some builders wire the main fuel pump with a pilot operated switch, which opens the door to unexpected pilot induced engine shutoffs.
Those things happen.
Wiring the main pump in series with an oil pressure switch is making the engine dependent on this switch for continued operation.
No problem for checking pump operation : the pumps are clearly audible from the cockpit.
Please note that we are talking about a Rotax engine here, the PM alternator rotor is keyed on the crankshaft at the rear of the engine.
In our project, we wired the main fuel pump direct from an auxiliary contact on the ignition keyswitch. The fuel pump runs any time the ignition is "on".
FWIW
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
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rampil
Joined: 04 May 2007
Posts: 870
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| Posted: Thu Oct 06, 2016 2:03 am Post subject: Re: rotax generator without battery |
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If your aux alternator is running off the spline takeoff in the back of
the gearbox, it is never turning at engine RPM and so will never
produce its max rated output of "40" amps. I don't see why you
are planning to just throw away the 15-16 amps from the engine's
alternator.
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user9253
Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan
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| Posted: Thu Oct 06, 2016 3:56 am Post subject: Re: rotax generator without battery |
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Yes, I suggested a momentary push button switch to bypass the oil pressure switch. A guarded maintained switch could be used instead.
Another option is to automatically energize the fuel pump whenever the starter is energized.
| Quote: | | Joe, how would I accomplish the engine start? The primary fuel pump needs the generator and the auxiliary needs oil pressure. Is that what the push button is for? |
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nuckolls.bob(at)aeroelect
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| Posted: Thu Oct 06, 2016 4:54 am Post subject: rotax generator without battery |
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At 04:48 PM 10/5/2016, you wrote:
| Quote: | Thanks Bob.Â
What would the effect be on the pump if it was getting less than ideal amps/volts? Would it simply lower the performance of the pump?Â
|
If you're talking about and electric,
"thump-thump" pump, you just about cannot
hurt these with any sort of electrical abuse
short of severe over voltage. Pioneered by
Bendix in the 60's, the motor that drives
the pump is simply a solenoid (originally
energized through a set of contacts no unlike
a switch relay) that compresses a spring which
in turn forces fuel out of the pump. As the
fuel flowed out under spring force, a pair
of check valves allowed fuel to be sucked in
behind the piston. When it reached end of
travel, contacts would close, solenoid would
pull the piston back thus re-compressing the
spring.
Modern versions are all solid state. In
the example you see here
http://tinyurl.com/hxwckfr
Figure 10 shows our old friend the 555 timer
used to periodically compress the spring with
a string of short pulses . . . energy applied
irrespective of flow rate through the pump.
This configuration offers an exceedingly
simple, robust design with very long service
life (the contacts would wear out on the
original Bendix design and were not repairable).
| Quote: | | Regarding automatic shut off of the pump, the master switch is hardly "automatic." The scenario would be one of a crash with injuries. We would want the electric fuel pump to shut down when the engine shuts down so that it does not continue to pump fuel, possibly into a ruptured fuel system. |
Electric fuel pumps have been used on aircraft
in various forms almost since day-one. The
POWER source for that device along with all
other electrically driven components offers
a potential ignition source for spilled fuel.
Hence the legacy requirement for crew accessible
control of all electrical sources in the form
of alternator/generator and battery switches.
The idea is that a pilot generally knows when
an off-field landing is imminent and will
shut off those energy sources before the
crash.
This 'new' push by Rotax to dedicate the
built-in PM alternator to running just one
fuel pump is a puzzlement . . .
In he past, this 18A alternator powered
entire airplanes . . . thousands of them. Now
see a suggestion that this capable source be
partitioned off to run one of the smallest
energy-demands in airplane . . . a thump-thump
pump.
Adding a 40A external alternator to the 912/914
engine offers a great opportunity to craft
a Z-13/8 style system in the airplane . . . except
it's a Z-13/18 with about twice the stand-by
power of the original Z-13/8.
This two-layered electrical system is about as
robust with respect to failure modes as you can
get. One pump would run from the battery bus,
the second from the e-bus . . . or main bus . . .
it wouldn't much matter with that large a stand-
by energy source.
This thing Rotax recommends for dedicating an
18A alternator to running just one pump is,
in my not so humble opinion, just silly.
Bob . . .
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nuckolls.bob(at)aeroelect
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| Posted: Thu Oct 06, 2016 5:03 am Post subject: rotax generator without battery |
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At 05:56 PM 10/5/2016, you wrote:
| Quote: | | That may be true, but the Rotax 912iS and the UL Power engines do shut off fuel pumps when the engine stops as do all modern automobiles. Again, I am not concerned with a forced landing where there is time to prepare. I am concerned with a crash, such as flipping the aircraft due to soft or rough terrain, or a million other things that could conceivably happen (and do happen). In such an instance, I would prefer not to have a high pressure fuel pump doing its job. |
You say "high-pressure" . . . is this no longer
the solenoid driven spring style pump I described
earlier? Is the 912/914 now fuel-injected?
In any case, you can achieve the automatic shut
off in the same way that cars have for decades.
My truck uses an oil pressure switch to keep
the pump running with a bypass relay energized
by the starter switch to get fuel pressure while
cranking. Your 'bypass' could be a simple diode
off the starter engagement line that feeds power
directly to the pump while cranking.
Bob . . .
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user9253
Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan
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| Posted: Thu Oct 06, 2016 5:33 am Post subject: Re: rotax generator without battery |
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The Rotax 912 (with carburetor) has an engine driven fuel pump, so the engine is not electrically dependent. The Rotax 914iS fuel injected engine is electrically dependent with two high pressure fuel pumps. It seems that the Rotax engineers (and lawyers) do not trust aircraft electrical systems to be fail safe. Thus they have dedicated the flywheel dynamo to powering only a fuel pump.
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gilles.thesee(at)free.fr
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| Posted: Thu Oct 06, 2016 6:00 am Post subject: rotax generator without battery |
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Le 06/10/2016 à 14:53, Robert L. Nuckolls, III a écrit :
| Quote: |
If you're talking about and electric,
"thump-thump" pump, |
Hi Bob and all,
Just to say that the Rotax 914 pumps are the rotary vane type from Pierburg, like some German cars.
http://contrails.free.fr/engine_pierburg_en.php
FWIW,
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Thu Oct 06, 2016 7:42 am Post subject: rotax generator without battery |
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Bob, the 914 engine is not fuel injected, but it is turbocharged and there is a fuel pressure regulator that maintains a constant fuel pressure over air pressure produced by the turbo. From what I can tell, it works the same as injection in that a lot of fuel is pumped to the regulator, but most of that is returned to the tank. I have no idea what a thump-thump pump is, but I believe the Rotax pumps are the same type as used in fuel injected automobiles.
Ira, the 40 amp aux is belt driven.
On Thu, Oct 6, 2016 at 5:59 AM, GTH <gilles.thesee(at)free.fr (gilles.thesee(at)free.fr)> wrote:
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nuckolls.bob(at)aeroelect
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| Posted: Thu Oct 06, 2016 7:56 am Post subject: rotax generator without battery |
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At 08:59 AM 10/6/2016, you wrote:
| Quote: | Le 06/10/2016 à 14:53, Robert L. Nuckolls, III a écrit :
| Quote: |
If you're talking about and electric,
"thump-thump" pump, |
Hi Bob and all,
Just to say that the Rotax 914 pumps are the rotary vane type from Pierburg, like some German cars.
http://contrails.free.fr/engine_pierburg_en.php |
Thanks. Okay, on the order of 30psi max. Do we
know what the cracking pressure is for the
fuel return line?
The specs call for not more than 4.3A which
would be at static pressure rating. This
will be reduced in approximate proportion
to the fuel control system pressure relief
settings.
It would be a valuable knowledge-nugget to contribute
to the library if someone made a real-time
measurement of fuel pump current in this system,
--> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>
The Rotax 912 (with carburetor) has an engine driven fuel pump, so the engine is not electrically dependent. The Rotax 914iS fuel injected engine is electrically dependent with two high pressure fuel pumps. It seems that the Rotax engineers (and lawyers) do not trust aircraft electrical systems to be fail safe. Thus they have dedicated the flywheel dynamo to powering only a fuel pump.
Hmmmm . . . I wonder from whence their
discomforts are derived? A study of the aviation
accident reports shows that loss of electrical
power is almost never a contributing factor
in loss of engine . . . and it's an easy task
to craft a failure tolerant system that
insures sources of energy vital to engine
operation.
Z-13/8 evolved out of decades of experience
and observation of aircraft operations in
both TC and OBAM aviation venues. I would
really appreciate it if anyone associated
with Rotax or any other institution could
show by considered FMEA how any aircraft
fitted with Z-13/x is likely to suffer engine
failure due to any single failure within
the system.
Some cultures find comfort in staffing
committees of individuals paid to worry.
All too often, work product of such
committees fails the common sense approach
to failure effects analysis.
I observe that common sense is inversely
proportional to the bureaucratization
of the institution. My last stint in
TC aviation offered me an inside observation
of the merger of Beech/Hawker/Cessna into
one big Textron operation. The very
FIRST field failure problem I was asked
to assist with had a STONE simple, two
week solution made possible by the merger
of the two inventories of qualified
products . . . a foaming at the mouth
field failure on one brand was easily
mittigated by replacement of a decades
old, field proven part from the other
brand. The last meeting I attended before
my consulting contract ran out left me
with a feeling of satisfaction of having
identified a short path to an elegant
solution.
To my dismay, nearly a year later I was
told that there were 'problems' with the
solution having nothing to do with form,
fit, function and everything to do with
differences of opinion from a parade of
bureaucrats with 'worries' and regulatory
barriers . . . I shudder to think of dozens
of customers with million dollar airplanes;
the foam around their mouths getting dried out,
crusty and flaking off. I don't know
they get an airplane built anymore.
Walter, Clyde, Olive Ann, Hedrick,
et. als. would be horrified to see what
we've done to their airplane companies.
My gut feeling is that Rotax is/has
become similarly afflicted with bureaucratic
worriers lacking foundation in physics
and practical experience. This is a
disease that is horribly taxing on one's
ability to offer good value with
un-impeachable confidence. In some instances
it is terminal.
In any case, I'm still unconvinced that the
dedication of a rather capable energy source
to the operation of a single, low energy
task for which a back-up already exists
is a solution seriously lacking elegance.
Bob . . .
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nuckolls.bob(at)aeroelect
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| Posted: Thu Oct 06, 2016 12:46 pm Post subject: rotax generator without battery |
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At 10:39 AM 10/6/2016, you wrote:
| Quote: | | Bob, the 914 engine is not fuel injected, but it is turbocharged and there is a fuel pressure regulator that maintains a constant fuel pressure over air pressure produced by the turbo. |
Do you know what the pressure setting is?
Bob . . .
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gilles.thesee(at)free.fr
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| Posted: Thu Oct 06, 2016 1:00 pm Post subject: rotax generator without battery |
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Le 06/10/2016 à 22:42, Robert L. Nuckolls, III a écrit :
| Quote: | At 10:39 AM 10/6/2016, you wrote:
| Quote: | | Bob, the 914 engine is not fuel injected, but it is turbocharged and there is a fuel pressure regulator that maintains a constant fuel pressure over air pressure produced by the turbo. |
Do you know what the pressure setting is?
|
Airbox pressure + 0.25 bar (+- 0.10 bar)
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
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