---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 04/28/10: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:42 AM - Re: Sil Pad For Schottky Diode (Robert L. Nuckolls, III) 2. 07:22 AM - Hour-meter switch from 3-phase tach generator (Robert L. Nuckolls, III) 3. 07:24 AM - One or Two batteries with Single Alternator for Electric Airplane (Kevin Sheely) 4. 09:12 AM - Re: stopping engine (Kenneth Johnson) 5. 09:21 AM - Re: Big load on BAT BUS (jonlaury) 6. 09:42 AM - Re: stopping engine (Mike Fontenot) 7. 10:11 AM - Re: stopping engine (Bill Bradburry) 8. 10:54 AM - Re: stopping engine (Bill Bradburry) 9. 11:09 AM - Re: stopping engine (Matt Prather) 10. 07:49 PM - Electrical diagram (marchudson) 11. 08:12 PM - Re: stopping engine (Bill Schertz) 12. 08:36 PM - Re: One or Two batteries with Single Alternator for Electric Airplane (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:42:47 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Sil Pad For Schottky Diode At 08:39 PM 4/27/2010, you wrote: >Bob, >I bought a Schottky Diode from you roughly one year ago. I >installed it today and was unable to get the device mounted so that >there was no conductivity between the load screw and the mounting >plate. I did not use excessive force on the screw and the holes are >all clean. I think the Sil Pad got damaged in the install. Can I >buy another one from you ? Shoot me your address and I'll send you one. Bob . . . //// (o o) ===========o00o=(_)=o00o======== < Go ahead, make my day . . . > < show me where I'm wrong. > ================================ ________________________________ Message 2 _____________________________________ Time: 07:22:13 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Hour-meter switch from 3-phase tach generator Some weeks back we had a discussion about how to switch a Hobbs meter on and off based on activity at the 3-phase tach generator. I thought we'd 'wrapped up' that discussion but I found a drawing under a stack of stuff that apparently didn't get posted. For those interested in such things, see: http://aeroelectric.com/Pictures/Schematics/Hour-Meter_from_3-Phase_Tach.pdf The opto-couplers can be anything with an open collector, transistor output. Bob . . . //// (o o) ===========o00o=(_)=o00o======== < Go ahead, make my day . . . > < show me where I'm wrong. > ================================ ________________________________ Message 3 _____________________________________ Time: 07:24:03 AM PST US From: Kevin Sheely Subject: AeroElectric-List: One or Two batteries with Single Alternator for Electric Airplane Bob,=0A=0AWhich architecture should I be using for a VFR, day/night, single engine dual LSE ignition, single B&C 30 amp alternator and single MGL EFIS , radio, transponder, intercom?=0A=0AMy emergency power draw would be 6.7 a mps (cruise-is 12.34 amps). I could use a single battery but would like t o have a second smaller 5-7 amp battery as a backup for the EFIS and-one of the LSE ignitions.=0A=0ARegards,=0AKevin ________________________________ Message 4 _____________________________________ Time: 09:12:57 AM PST US From: Kenneth Johnson Subject: Re: AeroElectric-List: stopping engine Hi All,=0AI would like to thank all who responded.=C2- =0A=0AIt would see m the best reason to stop an engine with fuel starvation would be to preven t possible danger from the prop.=C2- If a prop was repositioned, fuel in a cylinder might ignite, which in turn would turn the prop and that might h urt someone.=C2- In an automobile, if dieseling=C2-occurs, no is hurt. =C2- The car is in "Park" or "Neutral."=0A=0AI have a Mazda rotary engine I will be using for my airplane.=C2- Eventhough this is not a piston eng ine, the threat of danger from the prop with fuel left in the burn chamber still exists.=C2- For safety reasons, fuel starvation would be the best w ay to stop the engine.=C2- Turning off the ignition will stop current to the spark plugs, coils,=C2-and will turn off the high pressure fuel pump. =C2- However, it would seem that turning off the fuel pump before turning off the ignition would be a safer way to eliminate fuel from the burn cham bers.=0A=0ABy using a valve on my fuel rail, I could stop fuel.=C2- Howev er, the fuel pump would still be working and could be damaged.=C2- Again, it would seem that switching off the fuel pump=C2-before the ignition=C2 -might be the best solution.=C2- =0A=0AIf anyone has a better solution, please post.=0A=0AThanks,=0A=0AKen Johnson=C2-=C2-=0A=0A=0A=0A=0A_____ ___________________________=0AFrom: Matt Prather =0ATo: aeroelectric-list@matronics.com=0ASent: Tue, April 27, 2010 1:54:43 PM=0ASu bject: RE: AeroElectric-List: stopping engine=0A=0A--> AeroElectric-List me ssage posted by: "Matt Prather" =0A=0AI think it's worth while to be precise (reduce ambiguity) in matters such=0Aas this.=0A=0AI be lieve many (most?) light airplane POH's specify that engine shutdown=0Ais a ccomplished by moving the mixture control to idle-cutoff (ICO).=0AUsually t his causes the engine to stop running fairly rapidly - in a=0Amatter of a c ouple of seconds.=C2- Selecting rich mixture and hitting the=0Astarter us ually allows the engine to restart very quickly/easily.=0A=0ACertainly many airplanes still have Stromberg carbs (or similar) which=0Adon't have a mix ture control effective enough to cause "idle-cutoff".=C2- I=0Ahave ridden with pilots of such airplanes who only use the magneto=0Aswitches to stop the engine.=C2- One benefit of this procedure is that you=0Acheck to see if you have a "hot mag" on each flight.=C2- If the engine stops=0Adead, y ou can be somewhat certain that the p-lead circuit is in working=0Aconditio n.=0A=0AMost (all?) light airplanes also have at least one fuel control val ve=0A(selector), which can also be used to stop the flow of fuel to the eng ine.=0AOn the carbureted engines that I have operated, closing this fuel va lve=0Adoes eventually stop the engine, though depending on how low the thro ttle=0Asetting is, it might take a few minutes for the float bowl in the ca rb to=0Aget low enough to cause the engine to lean-out and die.=C2- Usual ly when I=0Apull up to a parking spot, I don't feel like waiting for the ca rb to=0Aempty, so I never do this.=0A=0AIf the fuel valve was turned off, o n carbureted airplanes with gravity=0Afeed fuel, turning on the fuel valve and waiting a few moments will refill=0Athe carb float bowl, at which point the engine may be restarted.=C2- For an=0Aairplane with pump driven fuel , turning on the electric pump will allow=0Arestarting much faster/sooner t han if only the engine driven pump is used.=0ATurning on the electric pump is often in the engine start procedure.=0A=0AIn an airplane that depends on a high pressure electric pump, I'm not sure=0Ait makes sense to "turn off the fuel," if that implies closing some kind=0Aof fuel valve.=C2- It migh t make more sense to turn off the electric pump(s).=0A=0AMy impression of a utomotive fuel injection is that turning the key off=0Astops power to both the ignition and the fuel pump(s).=C2- This leaves=0Aburnable mixture in the cylinders and intake manifold.=C2- In an airplane,=0Athis method of s topping the engine increases the risk of unexpected prop=0Amotion.=C2- Tu rning the key to run causes the fuel pump(s) to run until the=0Aspecified s ystem pressure is reached, at which point the pump(s) turn off.=0A=0AOne ot her thing I have noticed is that some electronic ignition systems=0Amay fir e the spark plugs one time when the system is energized.=C2- This will=0A likely cause the prop to turn if there is a burnable mixture in the=0Acylin ders.=C2- In fact, my Varieze has such a system.=C2- A number of times I=0Ahave actually had the engine start spontaneously because of this effect -=0Aprime with accelerator pump, walk the prop to pull fuel into the=0Acyl inders, turn on the ignition, and away it goes.=C2- So, magnetos aren't =0Athe only things that will fire unexpectedly.=C2- In fact, a mag withou t an=0Aimpulse couple isn't likely going to spark on its own..=0A=0ASo to g et back to the original question,=C2- I agree that stopping the fuel=0Ade livery in some way is generally a good idea.=C2- I think turning off the =0Apumps while leaving the ignition firing is the best bet, as that should =0Adump fuel system pressure, and yield the least burnable mixture in the =0Acylinders.=0A=0AWith all that said, everyone working around aircraft sho uld be very=0Acareful of the propeller, whatever method is used to stop the engine. =0APilots need to be vigilant to not allow anyone to haphazardly m ove the=0Aprop or stand in the prop arc.=0A=0A=0ARegards,=0A=0AMatt-=0A=0A> In an Aviation carb=99ed or injected engine, the shutoff method is t he=0A> same- turn off the fuel. The reason for this is to prevent a fuel/ai r=0A> mixture being left in a cylinder. If a P lead wire is broken and the =0A> propeller is turned, it could fire and injure someone. From your=0A> q uestion I assume you=99re installing an auto engine.=0A>=0A> Auto eng ines kill the spark. Some might also kill the pressure in the=0A> fuel rail . You=99re going to have to blas=C3=A9 your own trail here.=0A>=0A> B ruce=0A> www.Glasair.org=0A> -----Original Message-----=0A> From: owner-aer oelectric-list-server@matronics.com=0A> [mailto:owner-aeroelectric-list-ser ver@matronics.com] On Behalf Of=0A> Kenneth Johnson=0A> Sent: Tuesday, Apri l 27, 2010 12:45 PM=0A> To: aeroelectric-list@matronics.com=0A> Subject: Ae roElectric-List: stopping engine=0A>=0A> Aircraft Electrical Gurus,=0A> Thi s subject has been presented briefly recently, but I was looking for=0A> th e opinion of several.=C2- This may have an electrical solution of not.=0A > The question is: "What is the best way to stop your aircraft engine?=0A> =0A> In the recent past, at this site I have seen recommended a switch to t he=0A> fuel pump.=C2- Turn off the fuel pump and eventually the engine st ops.=0A>=0A> I rent Cessna 172 and the prefered way to stop the engine is t o minimize=0A> both the throttle and richness knobs by pulling them out.=C2 - Technically,=0A> what exactly does this do?=C2- Could I place a simpl e ball valve on my fuel=0A> rail and phsically close it?=C2- Is this what I do on the Cessna 172?=C2- The=0A> Cessna fuel is fed throught a carbur etor and my engine is fuel injected.=0A> Does that make a difference?=0A> =0A> On the automobile engine, when we turn off the engine, are we just=0A> closing the switch that provides current to the spark plugs, or is=0A> som ething else involved?=C2- Is this what should be done for the aircraft=0A > engine?=0A>=0A> Thanks for your advice.=0A>=0A> Ken Johnson=0A>=0A>=0A> -======================== =C2- =C2- =C2- =C2- =C2- =C2- =C2- =C2- =C2- =C2- -Matt =============0A=0A=0A ________________________________ Message 5 _____________________________________ Time: 09:21:03 AM PST US Subject: AeroElectric-List: Re: Big load on BAT BUS From: "jonlaury" klehman(at)albedo.net wrote: > There are details that aren't mentioned but I would be cautious with > this. ..snip... > > To understand where I am coming from, understand that the so called > "redundant" electronic engine systems that I've examined do not come > close to true redundancy. Most do not have dual injectors and most share > a single feed to the injectors. > > Ken > > Ken, Thanks for your observations and I'm sorry for the delayed response. My ISP has been down for awhile. It's not often that we have rain and low temps in April in Central Calif and the wireless system antenna on a 6500' peak took a load of ice and collapsed. My EFI system is the quasi-redundant type that you referred to. A single ECU, injectors, TPS, etc. I inquired about "dualing" up the system but they said that they had tried that and that the result, because of the additional complexities, was a far less reliable system than the single system. SDS has accumulated 15,000+ flight hours, over 12,000,000 ground ops hours and bench top set up that has been firing away, 24/7, for years, all without a single equipment failure that was not caused by customer wiring/installation errors. MTBF far exceeds that of any reciprocating engine. I decided that the track record that Simple Digital Systems has accumulated gave me sufficient confidence to run the single system. BUT... as long as I had multiple sources of power (2 alts, 1 bat), I wanted to hedge my bets by connecting my single EFI to all 3, via Z-13. The Z-32 contactor add-on will be the third power source after losing two alternators. John Read this topic online here: http://forums.matronics.com/viewtopic.php?p=296048#296048 ________________________________ Message 6 _____________________________________ Time: 09:42:06 AM PST US Subject: Re: AeroElectric-List: stopping engine From: Mike Fontenot I have a GEO engine, EFI is the EC2 system, with 2 fuel pumps going into a single line, then to the fuel rail. In that line is a 3 way valve that I ca n use to bypass the rail and spill back into the fuel tank. Turning off the engine by starving the fuel, yet keeping the pumps running smoothly works quite well. On Wed, Apr 28, 2010 at 10:11 AM, Kenneth Johnson wr ote: > Hi All, > I would like to thank all who responded. > > It would seem the best reason to stop an engine with fuel starvation woul d > be to prevent possible danger from the prop. If a prop was repositioned, > fuel in a cylinder might ignite, which in turn would turn the prop and th at > might hurt someone. In an automobile, if dieseling occurs, no is hurt. The > car is in "Park" or "Neutral." > > I have a Mazda rotary engine I will be using for my airplane. Eventhough > this is not a piston engine, the threat of danger from the prop with fuel > left in the burn chamber still exists. For safety reasons, fuel starvati on > would be the best way to stop the engine. Turning off the ignition will > stop current to the spark plugs, coils, and will turn off the high pressu re > fuel pump. However, it would seem that turning off the fuel pump before > turning off the ignition would be a safer way to eliminate fuel from the > burn chambers. > > By using a valve on my fuel rail, I could stop fuel. However, the fuel > pump would still be working and could be damaged. Again, it would seem t hat > switching off the fuel pump before the ignition might be the best solutio n. > > > If anyone has a better solution, please post. > > Thanks, > > Ken Johnson > > ------------------------------ > *From:* Matt Prather > *To:* aeroelectric-list@matronics.com > *Sent:* Tue, April 27, 2010 1:54:43 PM > *Subject:* RE: AeroElectric-List: stopping engine > t > > > > I think it's worthwhile to be precise (reduce ambiguity) in matters such > as this. > > I believe many (most?) light airplane POH's specify that engine shutdown > is accomplished by moving the mixture control to idle-cutoff (ICO). > Usually this causes the engine to stop running fairly rapidly - in a > matter of a couple of seconds. Selecting rich mixture and hitting the > starter usually allows the engine to restart very quickly/easily. > > Certainly many airplanes still have Stromberg carbs (or similar) which > don't have a mixture control effective enough to cause "idle-cutoff". I > have ridden with pilots of such airplanes who only use the magneto > switches to stop the engine. One benefit of this procedure is that you > check to see if you have a "hot mag" on each flight. If the engine stops > dead, you can be somewhat certain that the p-lead circuit is in working > condition. > > Most (all?) light airplanes also have at least one fuel control valve > (selector), which can also be used to stop the flow of fuel to the engine .. > On the carbureted engines that I have operated, closing this fuel valve > does eventually stop the engine, though depending on how low the throttle > setting is, it might take a few minutes for the float bowl in the carb to > get low enough to cause the engine to lean-out and die. Usually when I > pull up to a parking spot, I don't feel like waiting for the carb to > empty, so I never do this. > > If the fuel valve was turned off, on carbureted airplanes with gravity > feed fuel, turning on the fuel valve and waiting a few moments will refil l > the carb float bowl, at which point the engine may be restarted. For an > airplane with pump driven fuel, turning on the electric pump will allow > restarting much faster/sooner than if only the engine driven pump is used .. > Turning on the electric pump is often in the engine start procedure. > > In an airplane that depends on a high pressure electric pump, I'm not sur e > it makes sense to "turn off the fuel," if that implies closing some kind > of fuel valve. It might make more sense to turn off the electric pump(s) .. > > My impression of automotive fuel injection is that turning the key off > stops power to both the ignition and the fuel pump(s). This leaves > burnable mixture in the cylinders and intake manifold. In an airplane, > this method of stopping the engine increases the risk of unexpected prop > motion. Turning the key to run causes the fuel pump(s) to run until the > specified system pressure is reached, at which point the pump(s) turn off .. > > One other thing I have noticed is that some electronic ignition systems > may fire the spark plugs one time when the system is energized. This wil l > likely cause the prop to turn if there is a burnable mixture in the > cylinders. In fact, my Varieze has such a system. A number of times I > have actually had the engine start spontaneously because of this effect - > prime with accelerator pump, walk the prop to pull fuel into the > cylinders, turn on the ignition, and away it goes. So, magnetos aren't > the only things that will fire unexpectedly. In fact, a mag without an > impulse couple isn't likely going to spark on its own.. > > So to get back to the original question, I agree that stopping the fuel > delivery in some way is generally a good idea. I think turning off the > pumps while leaving the ignition firing is the best bet, as that should > dump fuel system pressure, and yield the least burnable mixture in the > cylinders. > > With all that said, everyone working around aircraft should be very > careful of the propeller, whatever method is used to stop the engine. > Pilots need to be vigilant to not allow anyone to haphazardly move the > prop or stand in the prop arc. > > > Regards, > > Matt- > > > In an Aviation carb=92ed or injected engine, the shutoff method is the > > same- turn off the fuel. The reason for this is to prevent a fuel/air > > mixture being left in a cylinder. If a P lead wire is broken and the > > propeller is turned, it could fire and injure someone. From your > > question I assume you=92re installing an auto engine. > > > > Auto engines kill the spark. Some might also kill the pressure in the > > fuel rail. You=92re going to have to blas=E9 your own trail here. > > > > Bruce > > www.Glasair.org > > -----Original Message----- > > From: owner-aeroelectric-list-server@matronics.com > > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > > Kenneth Johnson > > Sent: Tuesday, April 27, 2010 12:45 PM > > To: aeroelectric-list@matronics.com > > Subject: AeroElectric-List: stopping engine > > > > Aircraft Electrical Gurus, > > This subject has been presented briefly recently, but I was looking for > > the opinion of several. This may have an electrical solution of not. > > The question is: "What is the best way to stop your aircraft engine? > > > > In the recent past, at this site I have seen recommended a switch to th e > > fuel pump. Turn off the fuel pump and eventually the engine stops. > > > > I rent Cessna 172 and the prefered way to stop the engine is to minimiz e > > both the throttle and richness knobs by pulling them out. Technically, > > what exactly does this do? Could I place a simple ball valve on my fue l > > rail and phsically close it? Is this what I do on the Cessna 172? The > > Cessna fuel is fed throught a carburetor and my engine is fuel injected .. > > Does that make a difference? > > > > On the automobile engine, when we turn off the engine, are we just > > closing the switch that provides current to the spark plugs, or is > > something else involved? Is this what should be done for the aircraft > > engine? > > > > Thanks for your advice. > > > > Ken Johnson > > > > > > > > > > > * > =========== =========== =========== =========== > * > > -- Mike ====== Mike Fontenot Apex Consulting & Services LLC Lakewood, Colorado 303 / 731-6645 mikef AT apexconsultingservices DOT com ====== ________________________________ Message 7 _____________________________________ Time: 10:11:22 AM PST US From: "Bill Bradburry" Subject: RE: AeroElectric-List: stopping engine Ken, You didn=92t say if you have fuel injection or a carb on your Mazda rotary, but if you have FI, you can shut off the injectors and the engine will immediately stop due to fuel starvation. No fuel will be left in the rotor faces. The fuel regulator will then immediately open up to keep the fuel pressure at your set point, so the fuel pumps will not be adversely affected. In fact, this is the condition you will have the regulator and pumps in when you set the fuel pressure. This is the way it is designed to work so no damage will ensue. After the engine stops you can leisurely shut everything else down. There will be no fuel in the rotors so there will be no danger if you want to move the prop for whatever reason. If you have a carb, well, you are on your own.. :>) Bill B _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Kenneth Johnson Sent: Wednesday, April 28, 2010 12:11 PM Subject: Re: AeroElectric-List: stopping engine Hi All, I would like to thank all who responded. It would seem the best reason to stop an engine with fuel starvation would be to prevent possible danger from the prop. If a prop was repositioned, fuel in a cylinder might ignite, which in turn would turn the prop and that might hurt someone. In an automobile, if dieseling occurs, no is hurt. The car is in "Park" or "Neutral." I have a Mazda rotary engine I will be using for my airplane. Eventhough this is not a piston engine, the threat of danger from the prop with fuel left in the burn chamber still exists. For safety reasons, fuel starvation would be the best way to stop the engine. Turning off the ignition will stop current to the spark plugs, coils, and will turn off the high pressure fuel pump. However, it would seem that turning off the fuel pump before turning off the ignition would be a safer way to eliminate fuel from the burn chambers. By using a valve on my fuel rail, I could stop fuel. However, the fuel pump would still be working and could be damaged. Again, it would seem that switching off the fuel pump before the ignition might be the best solution. If anyone has a better solution, please post. Thanks, Ken Johnson _____ From: Matt Prather Sent: Tue, April 27, 2010 1:54:43 PM Subject: RE: AeroElectric-List: stopping engine I think it's worthwhile to be precise (reduce ambiguity) in matters such as this. I believe many (most?) light airplane POH's specify that engine shutdown is accomplished by moving the mixture control to idle-cutoff (ICO). Usually this causes the engine to stop running fairly rapidly - in a matter of a couple of seconds. Selecting rich mixture and hitting the starter usually allows the engine to restart very quickly/easily. Certainly many airplanes still have Stromberg carbs (or similar) which don't have a mixture control effective enough to cause "idle-cutoff". I have ridden with pilots of such airplanes who only use the magneto switches to stop the engine. One benefit of this procedure is that you check to see if you have a "hot mag" on each flight. If the engine stops dead, you can be somewhat certain that the p-lead circuit is in working condition. Most (all?) light airplanes also have at least one fuel control valve (selector), which can also be used to stop the flow of fuel to the engine. On the carbureted engines that I have operated, closing this fuel valve does eventually stop the engine, though depending on how low the throttle setting is, it might take a few minutes for the float bowl in the carb to get low enough to cause the engine to lean-out and die. Usually when I pull up to a parking spot, I don't feel like waiting for the carb to empty, so I never do this. If the fuel valve was turned off, on carbureted airplanes with gravity feed fuel, turning on the fuel valve and waiting a few moments will refill the carb float bowl, at which point the engine may be restarted. For an airplane with pump driven fuel, turning on the electric pump will allow restarting much faster/sooner than if only the engine driven pump is used. Turning on the electric pump is often in the engine start procedure. In an airplane that depends on a high pressure electric pump, I'm not sure it makes sense to "turn off the fuel," if that implies closing some kind of fuel valve. It might make more sense to turn off the electric pump(s). My impression of automotive fuel injection is that turning the key off stops power to both the ignition and the fuel pump(s). This leaves burnable mixture in the cylinders and intake manifold. In an airplane, this method of stopping the engine increases the risk of unexpected prop motion. Turning the key to run causes the fuel pump(s) to run until the specified system pressure is reached, at which point the pump(s) turn off. One other thing I have noticed is that some electronic ignition systems may fire the spark plugs one time when the system is energized. This will likely cause the prop to turn if there is a burnable mixture in the cylinders. In fact, my Varieze has such a system. A number of times I have actually had the engine start spontaneously because of this effect - prime with accelerator pump, walk the prop to pull fuel into the cylinders, turn on the ignition, and away it goes. So, magnetos aren't the only things that will fire unexpectedly. In fact, a mag without an impulse couple isn't likely going to spark on its own.. So to get back to the original question, I agree that stopping the fuel delivery in some way is generally a good idea. I think turning off the pumps while leaving the ignition firing is the best bet, as that should dump fuel system pressure, and yield the least burnable mixture in the cylinders. With all that said, everyone working around aircraft should be very careful of the propeller, whatever method is used to stop the engine. Pilots need to be vigilant to not allow anyone to haphazardly move the prop or stand in the prop arc. Regards, Matt- > In an Aviation carb=92ed or injected engine, the shutoff method is the > same- turn off the fuel. The reason for this is to prevent a fuel/air > mixture being left in a cylinder. If a P lead wire is broken and the > propeller is turned, it could fire and injure someone. From your > question I assume you=92re installing an auto engine. > > Auto engines kill the spark. Some might also kill the pressure in the > fuel rail. You=92re going to have to blas=E9 your own trail here. > > Bruce > www.Glasair.org > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > Kenneth Johnson > Sent: Tuesday, April 27, 2010 12:45 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: stopping engine > > Aircraft Electrical Gurus, > This subject has been presented briefly recently, but I was looking for > the opinion of several. This may have an electrical solution of not. > The question is: "What is the best way to stop your aircraft engine? > > In the recent past, at this site I have seen recommended a switch to the > fuel pump. Turn off the fuel pump and eventually the engine stops. > > I rent Cessna 172 and the prefered way to stop the engine is to minimize > both the throttle and richness knobs by pulling them out. Technically, > what exactly does this do? Could I place a simple ball valve on my fuel > rail and phsically close it? Is this what I do on the Cessna 172? The > Cessna fuel is fed throught a carburetor and my engine is fuel injected. > Does that make a difference? > > On the automobile engine, when we turn off the engine, are we just > closing the switch that provides current to the spark plugs, or is > something else involved? Is this what should be done for the aircraft > engine? > > Thanks for your advice. > > Ken Johnson > > > Subject: RE: AeroElectric-List: stopping engine Ken, If you are building a Mazda rotary for your plane you should really look into the rotary forum. There is a tremendous amount of knowledge available there. Come join us! http://mail.lancaironline.net:81/lists/flyrotary/List.html How to subscribe is at the lower right corner. Bill B _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Kenneth Johnson Sent: Wednesday, April 28, 2010 12:11 PM Subject: Re: AeroElectric-List: stopping engine Hi All, I would like to thank all who responded. It would seem the best reason to stop an engine with fuel starvation would be to prevent possible danger from the prop. If a prop was repositioned, fuel in a cylinder might ignite, which in turn would turn the prop and that might hurt someone. In an automobile, if dieseling occurs, no is hurt. The car is in "Park" or "Neutral." I have a Mazda rotary engine I will be using for my airplane. Eventhough this is not a piston engine, the threat of danger from the prop with fuel left in the burn chamber still exists. For safety reasons, fuel starvation would be the best way to stop the engine. Turning off the ignition will stop current to the spark plugs, coils, and will turn off the high pressure fuel pump. However, it would seem that turning off the fuel pump before turning off the ignition would be a safer way to eliminate fuel from the burn chambers. By using a valve on my fuel rail, I could stop fuel. However, the fuel pump would still be working and could be damaged. Again, it would seem that switching off the fuel pump before the ignition might be the best solution. If anyone has a better solution, please post. Thanks, Ken Johnson _____ From: Matt Prather Sent: Tue, April 27, 2010 1:54:43 PM Subject: RE: AeroElectric-List: stopping engine I think it's worthwhile to be precise (reduce ambiguity) in matters such as this. I believe many (most?) light airplane POH's specify that engine shutdown is accomplished by moving the mixture control to idle-cutoff (ICO). Usually this causes the engine to stop running fairly rapidly - in a matter of a couple of seconds. Selecting rich mixture and hitting the starter usually allows the engine to restart very quickly/easily. Certainly many airplanes still have Stromberg carbs (or similar) which don't have a mixture control effective enough to cause "idle-cutoff". I have ridden with pilots of such airplanes who only use the magneto switches to stop the engine. One benefit of this procedure is that you check to see if you have a "hot mag" on each flight. If the engine stops dead, you can be somewhat certain that the p-lead circuit is in working condition. Most (all?) light airplanes also have at least one fuel control valve (selector), which can also be used to stop the flow of fuel to the engine. On the carbureted engines that I have operated, closing this fuel valve does eventually stop the engine, though depending on how low the throttle setting is, it might take a few minutes for the float bowl in the carb to get low enough to cause the engine to lean-out and die. Usually when I pull up to a parking spot, I don't feel like waiting for the carb to empty, so I never do this. If the fuel valve was turned off, on carbureted airplanes with gravity feed fuel, turning on the fuel valve and waiting a few moments will refill the carb float bowl, at which point the engine may be restarted. For an airplane with pump driven fuel, turning on the electric pump will allow restarting much faster/sooner than if only the engine driven pump is used. Turning on the electric pump is often in the engine start procedure. In an airplane that depends on a high pressure electric pump, I'm not sure it makes sense to "turn off the fuel," if that implies closing some kind of fuel valve. It might make more sense to turn off the electric pump(s). My impression of automotive fuel injection is that turning the key off stops power to both the ignition and the fuel pump(s). This leaves burnable mixture in the cylinders and intake manifold. In an airplane, this method of stopping the engine increases the risk of unexpected prop motion. Turning the key to run causes the fuel pump(s) to run until the specified system pressure is reached, at which point the pump(s) turn off. One other thing I have noticed is that some electronic ignition systems may fire the spark plugs one time when the system is energized. This will likely cause the prop to turn if there is a burnable mixture in the cylinders. In fact, my Varieze has such a system. A number of times I have actually had the engine start spontaneously because of this effect - prime with accelerator pump, walk the prop to pull fuel into the cylinders, turn on the ignition, and away it goes. So, magnetos aren't the only things that will fire unexpectedly. In fact, a mag without an impulse couple isn't likely going to spark on its own.. So to get back to the original question, I agree that stopping the fuel delivery in some way is generally a good idea. I think turning off the pumps while leaving the ignition firing is the best bet, as that should dump fuel system pressure, and yield the least burnable mixture in the cylinders. With all that said, everyone working around aircraft should be very careful of the propeller, whatever method is used to stop the engine. Pilots need to be vigilant to not allow anyone to haphazardly move the prop or stand in the prop arc. Regards, Matt- > In an Aviation carb=92ed or injected engine, the shutoff method is the > same- turn off the fuel. The reason for this is to prevent a fuel/air > mixture being left in a cylinder. If a P lead wire is broken and the > propeller is turned, it could fire and injure someone. From your > question I assume you=92re installing an auto engine. > > Auto engines kill the spark. Some might also kill the pressure in the > fuel rail. You=92re going to have to blas=E9 your own trail here. > > Bruce > www.Glasair.org > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > Kenneth Johnson > Sent: Tuesday, April 27, 2010 12:45 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: stopping engine > > Aircraft Electrical Gurus, > This subject has been presented briefly recently, but I was looking for > the opinion of several. This may have an electrical solution of not. > The question is: "What is the best way to stop your aircraft engine? > > In the recent past, at this site I have seen recommended a switch to the > fuel pump. Turn off the fuel pump and eventually the engine stops. > > I rent Cessna 172 and the prefered way to stop the engine is to minimize > both the throttle and richness knobs by pulling them out. Technically, > what exactly does this do? Could I place a simple ball valve on my fuel > rail and phsically close it? Is this what I do on the Cessna 172? The > Cessna fuel is fed throught a carburetor and my engine is fuel injected. > Does that make a difference? > > On the automobile engine, when we turn off the engine, are we just > closing the switch that provides current to the spark plugs, or is > something else involved? Is this what should be done for the aircraft > engine? > > Thanks for your advice. > > Ken Johnson > > > Bill, My only concern about this (and it's probably a remote concern) is that if you have a leaking injector, it may dribble fuel into the engine after shutdown. Otherwise, this is very much analogous to pulling the mixture to ICO on an aircraft carb or mechanical injection. Matt- > Ken, > > You didnt say if you have fuel injection or a carb on your Mazda rotary, > but if you have FI, you can shut off the injectors and the engine will > immediately stop due to fuel starvation. No fuel will be left in the > rotor > faces. The fuel regulator will then immediately open up to keep the fuel > pressure at your set point, so the fuel pumps will not be adversely > affected. In fact, this is the condition you will have the regulator and > pumps in when you set the fuel pressure. This is the way it is designed > to > work so no damage will ensue. After the engine stops you can leisurely > shut > everything else down. There will be no fuel in the rotors so there will > be > no danger if you want to move the prop for whatever reason. > > If you have a carb, well, you are on your own.. :>) > > > Bill B > > > _____ > > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Kenneth > Johnson > Sent: Wednesday, April 28, 2010 12:11 PM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: stopping engine > > > Hi All, > > I would like to thank all who responded. > > > It would seem the best reason to stop an engine with fuel starvation would > be to prevent possible danger from the prop. If a prop was repositioned, > fuel in a cylinder might ignite, which in turn would turn the prop and > that > might hurt someone. In an automobile, if dieseling occurs, no is hurt. > The > car is in "Park" or "Neutral." > > > I have a Mazda rotary engine I will be using for my airplane. Eventhough > this is not a piston engine, the threat of danger from the prop with fuel > left in the burn chamber still exists. For safety reasons, fuel > starvation > would be the best way to stop the engine. Turning off the ignition will > stop current to the spark plugs, coils, and will turn off the high > pressure > fuel pump. However, it would seem that turning off the fuel pump before > turning off the ignition would be a safer way to eliminate fuel from the > burn chambers. > > > By using a valve on my fuel rail, I could stop fuel. However, the fuel > pump > would still be working and could be damaged. Again, it would seem that > switching off the fuel pump before the ignition might be the best > solution. > > > If anyone has a better solution, please post. > > > Thanks, > > > Ken Johnson > > > _____ > > From: Matt Prather > To: aeroelectric-list@matronics.com > Sent: Tue, April 27, 2010 1:54:43 PM > Subject: RE: AeroElectric-List: stopping engine > > > > I think it's worthwhile to be precise (reduce ambiguity) in matters such > as this. > > I believe many (most?) light airplane POH's specify that engine shutdown > is accomplished by moving the mixture control to idle-cutoff (ICO). > Usually this causes the engine to stop running fairly rapidly - in a > matter of a couple of seconds. Selecting rich mixture and hitting the > starter usually allows the engine to restart very quickly/easily. > > Certainly many airplanes still have Stromberg carbs (or similar) which > don't have a mixture control effective enough to cause "idle-cutoff". I > have ridden with pilots of such airplanes who only use the magneto > switches to stop the engine. One benefit of this procedure is that you > check to see if you have a "hot mag" on each flight. If the engine stops > dead, you can be somewhat certain that the p-lead circuit is in working > condition. > > Most (all?) light airplanes also have at least one fuel control valve > (selector), which can also be used to stop the flow of fuel to the engine. > On the carbureted engines that I have operated, closing this fuel valve > does eventually stop the engine, though depending on how low the throttle > setting is, it might take a few minutes for the float bowl in the carb to > get low enough to cause the engine to lean-out and die. Usually when I > pull up to a parking spot, I don't feel like waiting for the carb to > empty, so I never do this. > > If the fuel valve was turned off, on carbureted airplanes with gravity > feed fuel, turning on the fuel valve and waiting a few moments will refill > the carb float bowl, at which point the engine may be restarted. For an > airplane with pump driven fuel, turning on the electric pump will allow > restarting much faster/sooner than if only the engine driven pump is used. > Turning on the electric pump is often in the engine start procedure. > > In an airplane that depends on a high pressure electric pump, I'm not sure > it makes sense to "turn off the fuel," if that implies closing some kind > of fuel valve. It might make more sense to turn off the electric pump(s). > > My impression of automotive fuel injection is that turning the key off > stops power to both the ignition and the fuel pump(s). This leaves > burnable mixture in the cylinders and intake manifold. In an airplane, > this method of stopping the engine increases the risk of unexpected prop > motion. Turning the key to run causes the fuel pump(s) to run until the > specified system pressure is reached, at which point the pump(s) turn off. > > One other thing I have noticed is that some electronic ignition systems > may fire the spark plugs one time when the system is energized. This will > likely cause the prop to turn if there is a burnable mixture in the > cylinders. In fact, my Varieze has such a system. A number of times I > have actually had the engine start spontaneously because of this effect - > prime with accelerator pump, walk the prop to pull fuel into the > cylinders, turn on the ignition, and away it goes. So, magnetos aren't > the only things that will fire unexpectedly. In fact, a mag without an > impulse couple isn't likely going to spark on its own.. > > So to get back to the original question, I agree that stopping the fuel > delivery in some way is generally a good idea. I think turning off the > pumps while leaving the ignition firing is the best bet, as that should > dump fuel system pressure, and yield the least burnable mixture in the > cylinders. > > With all that said, everyone working around aircraft should be very > careful of the propeller, whatever method is used to stop the engine. > Pilots need to be vigilant to not allow anyone to haphazardly move the > prop or stand in the prop arc. > > > Regards, > > Matt- > >> In an Aviation carbed or injected engine, the shutoff method is the >> same- turn off the fuel. The reason for this is to prevent a fuel/air >> mixture being left in a cylinder. If a P lead wire is broken and the >> propeller is turned, it could fire and injure someone. From your >> question I assume youre installing an auto engine. >> >> Auto engines kill the spark. Some might also kill the pressure in the >> fuel rail. Youre going to have to blas your own trail here. >> >> Bruce >> www.Glasair.org >> -----Original Message----- >> From: owner-aeroelectric-list-server@matronics.com >> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of >> Kenneth Johnson >> Sent: Tuesday, April 27, 2010 12:45 PM >> To: aeroelectric-list@matronics.com >> Subject: AeroElectric-List: stopping engine >> >> Aircraft Electrical Gurus, >> This subject has been presented briefly recently, but I was looking for >> the opinion of several. This may have an electrical solution of not. >> The question is: "What is the best way to stop your aircraft engine? >> >> In the recent past, at this site I have seen recommended a switch to the >> fuel pump. Turn off the fuel pump and eventually the engine stops. >> >> I rent Cessna 172 and the prefered way to stop the engine is to minimize >> both the throttle and richness knobs by pulling them out. Technically, >> what exactly does this do? Could I place a simple ball valve on my fuel >> rail and phsically close it? Is this what I do on the Cessna 172? The >> Cessna fuel is fed throught a carburetor and my engine is fuel injected. >> Does that make a difference? >> >> On the automobile engine, when we turn off the engine, are we just >> closing the switch that provides current to the spark plugs, or is >> something else involved? Is this what should be done for the aircraft >> engine? >> >> Thanks for your advice. >> >> Ken Johnson >> >> >> >> > ________________________________ Message 10 ____________________________________ Time: 07:49:30 PM PST US Subject: AeroElectric-List: Electrical diagram From: "marchudson" Was wondering if you guys could have a look at this diagram and tell me what you think. It is a variation of Z-11. A couple of things about the design. Aircraft will be flown IMC. Two EFIS panels with internal battery backup. The alternator is a Plane Power with internal regulator and crowbar over voltage protection. I talked to the engineers at Plane Power and they told me that that alternator would function just fine if the battery were hypothetically removed from the aircraft while it was running, hence no off-batt-gen switch. The start enable switch will be guarded and is an added safety item to the push button start. I have tried to consider as many failure modes as possible but am not nearly as savvy as many on this forum. Thanks in advance for inputs. Marc Read this topic online here: http://forums.matronics.com/viewtopic.php?p=296088#296088 Attachments: http://forums.matronics.com//files/elec_schematic11_667.jpg ________________________________ Message 11 ____________________________________ Time: 08:12:54 PM PST US From: "Bill Schertz" Subject: Re: AeroElectric-List: stopping engine I have Mazda Rotary with EC-2 and electric fuel pump. shut down consists of shutting off the fuel pump, engine dies quickly, and there is no residual pressure in the lines to leak past the injectors and cause flooding or richness on the start. Bill Schertz KIS Cruiser #4045 N343BS Phase I testing From: Bill Bradburry Sent: Wednesday, April 28, 2010 12:09 PM Subject: RE: AeroElectric-List: stopping engine Ken, You didn't say if you have fuel injection or a carb on your Mazda rotary, but if you have FI, you can shut off the injectors and the engine will immediately stop due to fuel starvation. No fuel will be left in the rotor faces. The fuel regulator will then immediately open up to keep the fuel pressure at your set point, so the fuel pumps will not be adversely affected. In fact, this is the condition you will have the regulator and pumps in when you set the fuel pressure. This is the way it is designed to work so no damage will ensue. After the engine stops you can leisurely shut everything else down. There will be no fuel in the rotors so there will be no danger if you want to move the prop for whatever reason. If you have a carb, well, you are on your own.. :>) Bill B ------------------------------------------------------------------------- ------- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Kenneth Johnson Sent: Wednesday, April 28, 2010 12:11 PM Subject: Re: AeroElectric-List: stopping engine Hi All, I would like to thank all who responded. It would seem the best reason to stop an engine with fuel starvation would be to prevent possible danger from the prop. If a prop was repositioned, fuel in a cylinder might ignite, which in turn would turn the prop and that might hurt someone. In an automobile, if dieseling occurs, no is hurt. The car is in "Park" or "Neutral." I have a Mazda rotary engine I will be using for my airplane. Eventhough this is not a piston engine, the threat of danger from the prop with fuel left in the burn chamber still exists. For safety reasons, fuel starvation would be the best way to stop the engine. Turning off the ignition will stop current to the spark plugs, coils, and will turn off the high pressure fuel pump. However, it would seem that turning off the fuel pump before turning off the ignition would be a safer way to eliminate fuel from the burn chambers. By using a valve on my fuel rail, I could stop fuel. However, the fuel pump would still be working and could be damaged. Again, it would seem that switching off the fuel pump before the ignition might be the best solution. If anyone has a better solution, please post. Thanks, Ken Johnson ------------------------------------------------------------------------- ------- From: Matt Prather Sent: Tue, April 27, 2010 1:54:43 PM Subject: RE: AeroElectric-List: stopping engine I think it's worthwhile to be precise (reduce ambiguity) in matters such as this. I believe many (most?) light airplane POH's specify that engine shutdown is accomplished by moving the mixture control to idle-cutoff (ICO). Usually this causes the engine to stop running fairly rapidly - in a matter of a couple of seconds. Selecting rich mixture and hitting the starter usually allows the engine to restart very quickly/easily. Certainly many airplanes still have Stromberg carbs (or similar) which don't have a mixture control effective enough to cause "idle-cutoff". I have ridden with pilots of such airplanes who only use the magneto switches to stop the engine. One benefit of this procedure is that you check to see if you have a "hot mag" on each flight. If the engine stops dead, you can be somewhat certain that the p-lead circuit is in working condition. Most (all?) light airplanes also have at least one fuel control valve (selector), which can also be used to stop the flow of fuel to the engine. On the carbureted engines that I have operated, closing this fuel valve does eventually stop the engine, though depending on how low the throttle setting is, it might take a few minutes for the float bowl in the carb to get low enough to cause the engine to lean-out and die. Usually when I pull up to a parking spot, I don't feel like waiting for the carb to empty, so I never do this. If the fuel valve was turned off, on carbureted airplanes with gravity feed fuel, turning on the fuel valve and waiting a few moments will refill the carb float bowl, at which point the engine may be restarted. For an airplane with pump driven fuel, turning on the electric pump will allow restarting much faster/sooner than if only the engine driven pump is used. Turning on the electric pump is often in the engine start procedure. In an airplane that depends on a high pressure electric pump, I'm not sure it makes sense to "turn off the fuel," if that implies closing some kind of fuel valve. It might make more sense to turn off the electric pump(s). My impression of automotive fuel injection is that turning the key off stops power to both the ignition and the fuel pump(s). This leaves burnable mixture in the cylinders and intake manifold. In an airplane, this method of stopping the engine increases the risk of unexpected prop motion. Turning the key to run causes the fuel pump(s) to run until the specified system pressure is reached, at which point the pump(s) turn off. One other thing I have noticed is that some electronic ignition systems may fire the spark plugs one time when the system is energized. This will likely cause the prop to turn if there is a burnable mixture in the cylinders. In fact, my Varieze has such a system. A number of times I have actually had the engine start spontaneously because of this effect - prime with accelerator pump, walk the prop to pull fuel into the cylinders, turn on the ignition, and away it goes. So, magnetos aren't the only things that will fire unexpectedly. In fact, a mag without an impulse couple isn't likely going to spark on its own.. So to get back to the original question, I agree that stopping the fuel delivery in some way is generally a good idea. I think turning off the pumps while leaving the ignition firing is the best bet, as that should dump fuel system pressure, and yield the least burnable mixture in the cylinders. With all that said, everyone working around aircraft should be very careful of the propeller, whatever method is used to stop the engine. Pilots need to be vigilant to not allow anyone to haphazardly move the prop or stand in the prop arc. Regards, Matt- > In an Aviation carb'ed or injected engine, the shutoff method is the > same- turn off the fuel. The reason for this is to prevent a fuel/air > mixture being left in a cylinder. If a P lead wire is broken and the > propeller is turned, it could fire and injure someone. From your > question I assume you're installing an auto engine. > > Auto engines kill the spark. Some might also kill the pressure in the > fuel rail. You're going to have to blas=E9 your own trail here. > > Bruce > www.Glasair.org > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > Kenneth Johnson > Sent: Tuesday, April 27, 2010 12:45 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: stopping engine > > Aircraft Electrical Gurus, > This subject has been presented briefly recently, but I was looking for > the opinion of several. This may have an electrical solution of not. > The question is: "What is the best way to stop your aircraft engine? > > In the recent past, at this site I have seen recommended a switch to the > fuel pump. Turn off the fuel pump and eventually the engine stops. > > I rent Cessna 172 and the prefered way to stop the engine is to minimize > both the throttle and richness knobs by pulling them out. Technically, > what exactly does this do? Could I place a simple ball valve on my fuel > rail and phsically close it? Is this what I do on the Cessna 172? The > Cessna fuel is fed throught a carburetor and my engine is fuel injected. > Does that make a difference? > > On the automobile engine, when we turn off the engine, are we just > closing the switch that provides current to the spark plugs, or is > something else involved? Is this what should be done for the aircraft > engine? > > Thanks for your advice. > > Ken Johnson > > > Subject: Re: AeroElectric-List: One or Two batteries with Single Alternator for Electric Airplane At 08:50 AM 4/28/2010, you wrote: >Bob, > >Which architecture should I be using for a VFR, day/night, single >engine dual LSE ignition, single B&C 30 amp alternator and single >MGL EFIS, radio, transponder, intercom? > >My emergency power draw would be 6.7 amps (cruise is 12.34 amps). I >could use a single battery but would like to have a second smaller >5-7 amp battery as a backup for the EFIS and one of the LSE ignitions. Consider Z-13/8 with one 17 a.h. battery. Does B&C offer a 30A alternator? LSE recommends two batteries for two ignitions. It's a higher cost of ownership and heavier system but it will perform as advertised. Bob . . . //// (o o) ===========o00o=(_)=o00o======== < Go ahead, make my day . . . > < show me where I'm wrong. > ================================ ------------------------------------------------------------------------------------- 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.