Original Posted By: jay@hsmpk12a-s2.Eng.Sun.COM (Janine Sunlin)
How many of us running automotive ignition systems daily, for distances of what?100,000 miles or more have ever had our engines quit because of ignition failure? The dual plugs positioned as they are in Aircooled aircraft engines do enhance the combustion process a little bit. (the slight drop as you do a mag check testifies to this) The failure rate of the Magneto however is fairly high! mostly due to the capacitors points and primary wiring. The automotive electronic ignition systems are very reliable and their hotter spark insures that the plug will not foul even with poor mixtures at startup. The only mod we should make is to remove the vacuum advance. (we run our engines in a narrow load range) and to provide a retard system if we hand start the engine. The saving grace in favour of mags is the complete lack of need for any other electrical system. The addition of plug holes and dual ignition in an engine not designed for it is very difficult and I would expect that you will get more reliability by making sure your ignition wiring is as well installed as possible. John Mc________________________________________________________________________________
Pietenpol-List: Re: chevy Poplar Piet/dual plugs
Pietenpol-List: Re: chevy Poplar Piet/dual plugs
Original Posted By: "Larry L. Neal"
Hi JohnWhen I talked to Larry Harrison he said he used the standard distributorwith the coil etc, all contained in the cap.,just hook up some 12 volts toit and go. Now if this is out in the wind and rain and weather howwaterproof can it be. How waterproof can I make it? This gives me someconcern. Any thoughts?Cheers Steve Yahn>How many of us running automotive ignition systems daily, for >distances of what?100,000 miles or more have ever had our engines >quit because of ignition failure? The dual plugs positioned as they >are in Aircooled aircraft engines do enhance the combustion process a >little bit. (the slight drop as you do a mag check testifies to >this) The failure rate of the Magneto however is fairly high! mostly >due to the capacitors points and primary wiring. The automotive >electronic ignition systems are very reliable and their hotter spark >insures that the plug will not foul even with poor mixtures at >startup. The only mod we should make is to remove the vacuum advance. >(we run our engines in a narrow load range) and to provide a retard >system if we hand start the engine. The saving grace in favour of >mags is the complete lack of need for any other electrical system. >The addition of plug holes and dual ignition in an engine not >designed for it is very difficult and I would expect that you will >get more reliability by making sure your ignition wiring is as well >installed as possible.> John Mc>>________________________________________________________________________________
Hi JohnWhen I talked to Larry Harrison he said he used the standard distributorwith the coil etc, all contained in the cap.,just hook up some 12 volts toit and go. Now if this is out in the wind and rain and weather howwaterproof can it be. How waterproof can I make it? This gives me someconcern. Any thoughts?Cheers Steve Yahn>How many of us running automotive ignition systems daily, for >distances of what?100,000 miles or more have ever had our engines >quit because of ignition failure? The dual plugs positioned as they >are in Aircooled aircraft engines do enhance the combustion process a >little bit. (the slight drop as you do a mag check testifies to >this) The failure rate of the Magneto however is fairly high! mostly >due to the capacitors points and primary wiring. The automotive >electronic ignition systems are very reliable and their hotter spark >insures that the plug will not foul even with poor mixtures at >startup. The only mod we should make is to remove the vacuum advance. >(we run our engines in a narrow load range) and to provide a retard >system if we hand start the engine. The saving grace in favour of >mags is the complete lack of need for any other electrical system. >The addition of plug holes and dual ignition in an engine not >designed for it is very difficult and I would expect that you will >get more reliability by making sure your ignition wiring is as well >installed as possible.> John Mc>>________________________________________________________________________________
Pietenpol-List: Re: chevy Poplar Piet/dual plugs
Original Posted By: stephen
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Pietenpol-List: Re: chevy Poplar Piet/dual plugs
Original Posted By: LanhamOS
You can get a limited degree of dual ignition by usinga "coil splitter", basically a high voltage diode assembly,which lets you run two independent batteries, point sets,and coils, which would feed the single distributor and plug set. It gives redundancy to the most failure proneparts of the system.Only one system is on at a time. The ignition switchwould be set to left OR right. It's a popular setup with the "V6 STOL" crowd...The coil splitter is available at speed shops.johnk ________________________________________________________________________________
You can get a limited degree of dual ignition by usinga "coil splitter", basically a high voltage diode assembly,which lets you run two independent batteries, point sets,and coils, which would feed the single distributor and plug set. It gives redundancy to the most failure proneparts of the system.Only one system is on at a time. The ignition switchwould be set to left OR right. It's a popular setup with the "V6 STOL" crowd...The coil splitter is available at speed shops.johnk ________________________________________________________________________________
Pietenpol-List: Re: chevy Poplar Piet/dual plugs
Original Posted By: ADonJr
John,Good post! and I mostly agree. What we are talking about is ourtolerance for failure.I'm primarily a sailplane pilot and fly in central Texas farmlands, if Ilose my engine (or fail to find lift in my 1-26) no big deal. I'll landout and make some friends who never sat in an airplane before.Hook that same motor up to power my kid's heart lung machine and I'mimmediately in favor of triply redundant systems. Forget two mags, Iwant three plugs, MSD for each and real-time computer monitoring. Oh,did I mention oil sample spectrum analysis?Commercial, GA and Experimental, or more properly "Advanced DesignAircraft" should all take into account the proper model for systemsfailure tolerance while holding to the required mission specification.In other words, your Piet won't worry about one plug per piston, hasn'tfor 60 years. But if you can't afford to buy into thetriple-redundant-mentality, don't fly where you can't land.LarryMcNarry, John wrote:> How many of us running automotive ignition systems daily, for> distances of what?100,000 miles or more have ever had our engines> quit because of ignition failure? The dual plugs positioned as they> are in Aircooled aircraft engines do enhance the combustion process a> little bit. (the slight drop as you do a mag check testifies to> this) The failure rate of the Magneto however is fairly high! mostly> due to the capacitors points and primary wiring. The automotive> electronic ignition systems are very reliable and their hotter spark> insures that the plug will not foul even with poor mixtures at> startup. The only mod we should make is to remove the vacuum advance.> (we run our engines in a narrow load range) and to provide a retard> system if we hand start the engine. The saving grace in favour of> mags is the complete lack of need for any other electrical system.> The addition of plug holes and dual ignition in an engine not> designed for it is very difficult and I would expect that you will> get more reliability by making sure your ignition wiring is as well> installed as possible.> John Mc________________________________________________________________________________
John,Good post! and I mostly agree. What we are talking about is ourtolerance for failure.I'm primarily a sailplane pilot and fly in central Texas farmlands, if Ilose my engine (or fail to find lift in my 1-26) no big deal. I'll landout and make some friends who never sat in an airplane before.Hook that same motor up to power my kid's heart lung machine and I'mimmediately in favor of triply redundant systems. Forget two mags, Iwant three plugs, MSD for each and real-time computer monitoring. Oh,did I mention oil sample spectrum analysis?Commercial, GA and Experimental, or more properly "Advanced DesignAircraft" should all take into account the proper model for systemsfailure tolerance while holding to the required mission specification.In other words, your Piet won't worry about one plug per piston, hasn'tfor 60 years. But if you can't afford to buy into thetriple-redundant-mentality, don't fly where you can't land.LarryMcNarry, John wrote:> How many of us running automotive ignition systems daily, for> distances of what?100,000 miles or more have ever had our engines> quit because of ignition failure? The dual plugs positioned as they> are in Aircooled aircraft engines do enhance the combustion process a> little bit. (the slight drop as you do a mag check testifies to> this) The failure rate of the Magneto however is fairly high! mostly> due to the capacitors points and primary wiring. The automotive> electronic ignition systems are very reliable and their hotter spark> insures that the plug will not foul even with poor mixtures at> startup. The only mod we should make is to remove the vacuum advance.> (we run our engines in a narrow load range) and to provide a retard> system if we hand start the engine. The saving grace in favour of> mags is the complete lack of need for any other electrical system.> The addition of plug holes and dual ignition in an engine not> designed for it is very difficult and I would expect that you will> get more reliability by making sure your ignition wiring is as well> installed as possible.> John Mc________________________________________________________________________________
Pietenpol-List: Re: chevy Poplar Piet/dual plugs
Original Posted By: baileys(at)ktis.net (Robert M. Bailey)
Subject: Pietenpol-List: Re: chevy Poplar Piet/dual plugs> For JKahn.. do you have access to a Tiger Moth.. A great ship. Theyhave>one hanging in the lobby of the Helena Montana airport.. Dr. O Lanham>________________________________________________________________________________
Subject: Pietenpol-List: Re: chevy Poplar Piet/dual plugs> For JKahn.. do you have access to a Tiger Moth.. A great ship. Theyhave>one hanging in the lobby of the Helena Montana airport.. Dr. O Lanham>________________________________________________________________________________
Pietenpol-List: Re: chevy Poplar Piet/dual plugs
Original Posted By: Graham Hansen
For JKahn.. do you have access to a Tiger Moth.. A great ship. They haveone hanging in the lobby of the Helena Montana airport.. Dr. O Lanham________________________________________________________________________________
For JKahn.. do you have access to a Tiger Moth.. A great ship. They haveone hanging in the lobby of the Helena Montana airport.. Dr. O Lanham________________________________________________________________________________
Pietenpol-List: Re: chevy Poplar Piet/dual plugs
Original Posted By: Michael D Cuy
> >For JKahn.. do you have access to a Tiger Moth.. A great ship. They have> one hanging in the lobby of the Helena Montana airport.. Dr. O Lanham>Nope.. There's a few around here though. My late dad learned to fly in one inthe RCAF in '43.________________________________________________________________________________
> >For JKahn.. do you have access to a Tiger Moth.. A great ship. They have> one hanging in the lobby of the Helena Montana airport.. Dr. O Lanham>Nope.. There's a few around here though. My late dad learned to fly in one inthe RCAF in '43.________________________________________________________________________________