---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 10/05/16: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:34 AM - Re: Poisonous Battery Vapors? (Robert L. Nuckolls, III) 2. 12:58 PM - rotax generator without battery (Ken Ryan) 3. 02:07 PM - Re: rotax generator without battery (Robert L. Nuckolls, III) 4. 02:44 PM - Re: Poisonous Battery Vapors? (user9253) 5. 02:50 PM - Re: rotax generator without battery (Ken Ryan) 6. 03:40 PM - Re: rotax generator without battery (Alec Myers) 7. 03:58 PM - Re: rotax generator without battery (Ken Ryan) 8. 04:13 PM - Re: rotax generator without battery (Alec Myers) 9. 05:44 PM - Re: rotax generator without battery (user9253) 10. 06:08 PM - Re: Re: rotax generator without battery (Ken Ryan) 11. 06:10 PM - Re: Re: Poisonous Battery Vapors? (David Lloyd) 12. 06:39 PM - Re: rotax generator without battery (ashleysc@broadstripe.net) 13. 11:12 PM - Re: Re: rotax generator without battery (GTH) ________________________________ Message 1 _____________________________________ Time: 09:34:33 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Poisonous Battery Vapors? At 09:20 PM 10/4/2016, you wrote: > >Can lead acid batteries give off Hydrogen sulfide? If so, is it >safe to have batteries located within an aircraft cabin? A mother >and daughter might have been killed by battery vapors. >http://www.orlandosentinel.com/news/breaking-news/os-latifa-lincoln-dead-hydrogen-sulfide-20161004-story.html > >-------- It would be interesting to see the final report on any analysis generated by the hypothesis. A term search for "hydrogen sulfide" on batteryuniversity.com yielded three hits. http://tinyurl.com/hv6n6bt . . . it seems 'possible' that products of battery distress could include h2s . . . Our machines are usually fitted with ov protection. The quantity of liquid in the AGM battery is very limited. I suspect that demonstrations designed to produce H2S from a SVLA battery would be rather bizarre . . . unlikely to ever happen in vehicles . . . even less in airplanes. Bob . . . ________________________________ Message 2 _____________________________________ Time: 12:58:08 PM PST US From: Ken Ryan Subject: AeroElectric-List: 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? ________________________________ Message 3 _____________________________________ Time: 02:07:35 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: rotax generator without battery At 02:54 PM 10/5/2016, you wrote: >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 >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 . . . ________________________________ Message 4 _____________________________________ Time: 02:44:58 PM PST US Subject: AeroElectric-List: Re: Poisonous Battery Vapors? From: "user9253" Bob, Below is a quote from http://batteryuniversity.com/learn/article/health_concerns that you referenced. The danger of hydrogen sulfide is that the sense of smell acclimates to the gas and can not smell it anymore. That explains why the woman in the news article did not stop driving before she was incapacitated. > Over-charging a lead acid battery can produce hydrogen sulfide. The gas is colorless, very poisonous, flammable and has the odor of rotten eggs. Hydrogen sulfide also occurs naturally during the breakdown of organic matter in swamps and sewers; it is present in volcanic gases, natural gas and some well waters. Being heavier than air, the gas accumulates at the bottom of poorly ventilated spaces. Although noticeable at first, the sense of smell deadens the sensation with time and potential victims may be unaware of its presence. > As a simple guideline, hydrogen sulfide becomes harmful to human life if the odor is noticeable. Turn off the charger, vent the facility and stay outside until the odor disappears. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=460981#460981 ________________________________ Message 5 _____________________________________ Time: 02:50:39 PM PST US From: Ken Ryan Subject: Re: AeroElectric-List: rotax generator without battery 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@aeroelectric.com> wrote: > At 02:54 PM 10/5/2016, you wrote: > > 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 > > 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 . . . > ________________________________ Message 6 _____________________________________ Time: 03:40:07 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: rotax generator without battery There are about a zillion certified aircraft out there with electric fuel pu mps that are engaged and energised specifically for takeoff and landing. So y ou may be trying to solve a problem that isn't judged to arise very often; p articularly if you factor in the small but real possibility of whatever auto matic fuel pump shutoff mechanism you design engaging at the wrong moment (s hortly after takeoff, say) and causing the very accident you are hoping to a void. 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 w ell in advance of touchdown, as Bob suggests, by use of the master switch an d fuel shutoff. > On Oct 5, 2016, at 5:48 PM, Ken Ryan wrote: > > Thanks Bob. > > What would the effect be on the pump if it was getting less than ideal amp s/volts? Would it simply lower the performance of the pump? > > Regarding automatic shut off of the pump, the master switch is hardly "aut omatic." The scenario would be one of a crash with injuries. We would want t he electric fuel pump to shut down when the engine shuts down so that it doe s 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 wrote: >> At 02:54 PM 10/5/2016, you wrote: >>> 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) o ff the generator, and the auxiliary pump off the bus, which will be connecte d to a battery and the external 40 amp alternator. >>> >>> According to the Rotax 914 Installation Manual, the minimum idle rpm is 1 400, and at 1400 engine rpm the generator produces only 2a/13.5v (+/- 5%). T he pumps are Walbro GSL395. >>> >>> Is there any danger that this might be setting up a problem that would d amage either the regulator-rectifier or the fuel pump? >> >> No >> >>> Also, what would be the best way to insure that the auxiliary pump (if a ctivated) would automatically stop in the event of a crash? >> >> This is usually managed with the master switch . . . >> >> Bob . . . >> > ________________________________ Message 7 _____________________________________ Time: 03:58:54 PM PST US From: Ken Ryan Subject: Re: AeroElectric-List: rotax generator without battery 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 wrote: > 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 wrote: > > 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@aeroelectric.com> wrote: > >> At 02:54 PM 10/5/2016, you wrote: >> >> 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 >> >> 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 . . . >> > > ________________________________ Message 8 _____________________________________ Time: 04:13:37 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: rotax generator without battery Perhaps more practice at landing...? > On Oct 5, 2016, at 6:56 PM, Ken Ryan wrote: > > 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 n ot concerned with a forced landing where there is time to prepare. I am conc erned with a crash, such as flipping the aircraft due to soft or rough terra in, 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 d oing its job. > > >> On Wed, Oct 5, 2016 at 2:35 PM, Alec Myers wrote: >> There are about a zillion certified aircraft out there with electric fuel pumps that are engaged and energised specifically for takeoff and landing. S o 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 a utomatic fuel pump shutoff mechanism you design engaging at the wrong moment (shortly after takeoff, say) and causing the very accident you are hoping t o avoid. >> >> For an expectedly rough landing in the event of a forced approach onto ro ugh terrain, the fuel and electrical systems should all be purged and isolat ed well in advance of touchdown, as Bob suggests, by use of the master switc h and fuel shutoff. >> >> >> >>> On Oct 5, 2016, at 5:48 PM, Ken Ryan wrote: >>> >>> Thanks Bob. >>> >>> What would the effect be on the pump if it was getting less than ideal a mps/volts? Would it simply lower the performance of the pump? >>> >>> Regarding automatic shut off of the pump, the master switch is hardly "a utomatic." 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 d oes 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 wrote: >>>> At 02:54 PM 10/5/2016, you wrote: >>>>> I am designing my electrical system for the Rotax 914 which requires t wo 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 connec ted to a battery and the external 40 amp alternator. >>>>> >>>>> According to the Rotax 914 Installation Manual, the minimum idle rpm i s 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 >>>> >>>>> 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 . . . >>>> >>> > ________________________________ Message 9 _____________________________________ Time: 05:44:05 PM PST US Subject: AeroElectric-List: Re: rotax generator without battery From: "user9253" 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 ________________________________ Message 10 ____________________________________ Time: 06:08:57 PM PST US From: Ken Ryan Subject: Re: AeroElectric-List: Re: rotax generator without battery 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" wrote: 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 ________________________________ Message 11 ____________________________________ Time: 06:10:36 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: Re: Poisonous Battery Vapors? We had this happen one time on a drive into Mexico for winter duck hunting. We drove in friends old Suburban as it was pretty much bullet proof in the Baja outback conditions. I the way down, at night, I got the distinct smell of "burning french fries. . .". That is how my nose translated the problem Turned out the regulator had failed and the battery was being charged way beyond its design max limits. Very hot and fluids coming out the vent caps, etc. It was the smell that tipped us off. Never dawned on us that the nasty discharge would be dangerous other than eating up a battery box steel. I don't recall the details now, but, we did a work around such that the battery was not being charged for the remainder of the trip. Small Mexican city got us running again as they had parts and pieces. ----- Original Message ----- From: "user9253" Sent: Wednesday, October 05, 2016 2:43 PM Subject: AeroElectric-List: Re: Poisonous Battery Vapors? > > Bob, > Below is a quote from > http://batteryuniversity.com/learn/article/health_concerns that you > referenced. > The danger of hydrogen sulfide is that the sense of smell acclimates to > the gas and can not smell it anymore. That explains why the woman in the > news article did not stop driving before she was incapacitated. > >> Over-charging a lead acid battery can produce hydrogen sulfide. The gas >> is colorless, very poisonous, flammable and has the odor of rotten eggs. >> Hydrogen sulfide also occurs naturally during the breakdown of organic >> matter in swamps and sewers; it is present in volcanic gases, natural gas >> and some well waters. Being heavier than air, the gas accumulates at the >> bottom of poorly ventilated spaces. Although noticeable at first, the >> sense of smell deadens the sensation with time and potential victims may >> be unaware of its presence. >> As a simple guideline, hydrogen sulfide becomes harmful to human life if >> the odor is noticeable. Turn off the charger, vent the facility and stay >> outside until the odor disappears. > > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=460981#460981 > > > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 12 ____________________________________ Time: 06:39:23 PM PST US From: ashleysc@broadstripe.net Subject: Re: AeroElectric-List: rotax generator without battery 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. ----- Original Message ----- From: "Ken Ryan" Sent: Wednesday, October 5, 2016 12:54:16 PM Subject: AeroElectric-List: 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? ________________________________ Message 13 ____________________________________ Time: 11:12:24 PM PST US Subject: Re: AeroElectric-List: Re: rotax generator without battery From: GTH Le 06/10/2016 02:42, user9253 a crit : > > 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. > 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 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.