Magneto
#51
Guest
Posts: n/a
Re: Magneto
On 01 Dec 2003 02:19 PM, Lon Stowell posted the following:
> Approximately 12/1/03 13:44, CRWLR uttered for posterity:
>
>> I think that if a magneto ignition was suitable for use on an
>> automobile, then we would still be using them today instead of having
>> devised a means of getting rid of them 70-some-odd years ago.
>
> Judson magnetos were still popular as a more reliable and
> higher performance replacement for the stock ignition in
> British sports cars a mere 35-40 years ago. Whether this
> is evidence of merit for the magneto or a comment on
> British electrics may be a matter of personal opinion.
As the owner of a 1959 MGA, I am inclined to believe the latter. When I
finally get around to restoring my car, the Lucas distributor will be
fitted with one of the available drop-in electronic ignition modules.
That way, it will look stock and run better.
> As soon as good high energy ignition systems from the
> manufacturers hit the streets, magnetos pretty much
> disappeared, only to be remembered by aging pilots and
> old farts.
Some of us are young farts, although a look in the mirror is starting to
show less hair than is supposed to be there. I think my '73 chev was
one of the last pickups that GM made that still used points. I
converted it to HEI about 3 years ago and it now runs better than it has
in at least 15 years, and it actually passed its first ever emmissions
inspection this past summer (that shocked the hell out of me). The gas
mileage still sucks though.
----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
> Approximately 12/1/03 13:44, CRWLR uttered for posterity:
>
>> I think that if a magneto ignition was suitable for use on an
>> automobile, then we would still be using them today instead of having
>> devised a means of getting rid of them 70-some-odd years ago.
>
> Judson magnetos were still popular as a more reliable and
> higher performance replacement for the stock ignition in
> British sports cars a mere 35-40 years ago. Whether this
> is evidence of merit for the magneto or a comment on
> British electrics may be a matter of personal opinion.
As the owner of a 1959 MGA, I am inclined to believe the latter. When I
finally get around to restoring my car, the Lucas distributor will be
fitted with one of the available drop-in electronic ignition modules.
That way, it will look stock and run better.
> As soon as good high energy ignition systems from the
> manufacturers hit the streets, magnetos pretty much
> disappeared, only to be remembered by aging pilots and
> old farts.
Some of us are young farts, although a look in the mirror is starting to
show less hair than is supposed to be there. I think my '73 chev was
one of the last pickups that GM made that still used points. I
converted it to HEI about 3 years ago and it now runs better than it has
in at least 15 years, and it actually passed its first ever emmissions
inspection this past summer (that shocked the hell out of me). The gas
mileage still sucks though.
----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
#52
Guest
Posts: n/a
Re: Magneto
On 01 Dec 2003 02:19 PM, Lon Stowell posted the following:
> Approximately 12/1/03 13:44, CRWLR uttered for posterity:
>
>> I think that if a magneto ignition was suitable for use on an
>> automobile, then we would still be using them today instead of having
>> devised a means of getting rid of them 70-some-odd years ago.
>
> Judson magnetos were still popular as a more reliable and
> higher performance replacement for the stock ignition in
> British sports cars a mere 35-40 years ago. Whether this
> is evidence of merit for the magneto or a comment on
> British electrics may be a matter of personal opinion.
As the owner of a 1959 MGA, I am inclined to believe the latter. When I
finally get around to restoring my car, the Lucas distributor will be
fitted with one of the available drop-in electronic ignition modules.
That way, it will look stock and run better.
> As soon as good high energy ignition systems from the
> manufacturers hit the streets, magnetos pretty much
> disappeared, only to be remembered by aging pilots and
> old farts.
Some of us are young farts, although a look in the mirror is starting to
show less hair than is supposed to be there. I think my '73 chev was
one of the last pickups that GM made that still used points. I
converted it to HEI about 3 years ago and it now runs better than it has
in at least 15 years, and it actually passed its first ever emmissions
inspection this past summer (that shocked the hell out of me). The gas
mileage still sucks though.
----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
> Approximately 12/1/03 13:44, CRWLR uttered for posterity:
>
>> I think that if a magneto ignition was suitable for use on an
>> automobile, then we would still be using them today instead of having
>> devised a means of getting rid of them 70-some-odd years ago.
>
> Judson magnetos were still popular as a more reliable and
> higher performance replacement for the stock ignition in
> British sports cars a mere 35-40 years ago. Whether this
> is evidence of merit for the magneto or a comment on
> British electrics may be a matter of personal opinion.
As the owner of a 1959 MGA, I am inclined to believe the latter. When I
finally get around to restoring my car, the Lucas distributor will be
fitted with one of the available drop-in electronic ignition modules.
That way, it will look stock and run better.
> As soon as good high energy ignition systems from the
> manufacturers hit the streets, magnetos pretty much
> disappeared, only to be remembered by aging pilots and
> old farts.
Some of us are young farts, although a look in the mirror is starting to
show less hair than is supposed to be there. I think my '73 chev was
one of the last pickups that GM made that still used points. I
converted it to HEI about 3 years ago and it now runs better than it has
in at least 15 years, and it actually passed its first ever emmissions
inspection this past summer (that shocked the hell out of me). The gas
mileage still sucks though.
----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
#53
Guest
Posts: n/a
Re: Magneto
A/C require a dual ignition system per the FAA. They run
independantly and one at a time - part of the pre=flight is to switch
mags and watch for an RPM drop. I was damned glad to have mag
ingintion a couple of times when the rest of the electrical system
went AWOL on me <g>.
Best use I ever saw for a suplus C-47 magneto was the one somebody
hooked up to a young female teacher's chair (which happend to be U. S.
Gov't issue metal) then gave it a good spin about the time she sat
down. Class dismissed!
On Mon, 1 Dec 2003 22:02:33 UTC "CRWLR" <beerman@yahoo.com> wrote:
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
>
>
>
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/
>
--
Will Honea <whonea@codenet.net>
independantly and one at a time - part of the pre=flight is to switch
mags and watch for an RPM drop. I was damned glad to have mag
ingintion a couple of times when the rest of the electrical system
went AWOL on me <g>.
Best use I ever saw for a suplus C-47 magneto was the one somebody
hooked up to a young female teacher's chair (which happend to be U. S.
Gov't issue metal) then gave it a good spin about the time she sat
down. Class dismissed!
On Mon, 1 Dec 2003 22:02:33 UTC "CRWLR" <beerman@yahoo.com> wrote:
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
>
>
>
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/
>
--
Will Honea <whonea@codenet.net>
#54
Guest
Posts: n/a
Re: Magneto
A/C require a dual ignition system per the FAA. They run
independantly and one at a time - part of the pre=flight is to switch
mags and watch for an RPM drop. I was damned glad to have mag
ingintion a couple of times when the rest of the electrical system
went AWOL on me <g>.
Best use I ever saw for a suplus C-47 magneto was the one somebody
hooked up to a young female teacher's chair (which happend to be U. S.
Gov't issue metal) then gave it a good spin about the time she sat
down. Class dismissed!
On Mon, 1 Dec 2003 22:02:33 UTC "CRWLR" <beerman@yahoo.com> wrote:
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
>
>
>
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/
>
--
Will Honea <whonea@codenet.net>
independantly and one at a time - part of the pre=flight is to switch
mags and watch for an RPM drop. I was damned glad to have mag
ingintion a couple of times when the rest of the electrical system
went AWOL on me <g>.
Best use I ever saw for a suplus C-47 magneto was the one somebody
hooked up to a young female teacher's chair (which happend to be U. S.
Gov't issue metal) then gave it a good spin about the time she sat
down. Class dismissed!
On Mon, 1 Dec 2003 22:02:33 UTC "CRWLR" <beerman@yahoo.com> wrote:
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
>
>
>
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/
>
--
Will Honea <whonea@codenet.net>
#55
Guest
Posts: n/a
Re: Magneto
A/C require a dual ignition system per the FAA. They run
independantly and one at a time - part of the pre=flight is to switch
mags and watch for an RPM drop. I was damned glad to have mag
ingintion a couple of times when the rest of the electrical system
went AWOL on me <g>.
Best use I ever saw for a suplus C-47 magneto was the one somebody
hooked up to a young female teacher's chair (which happend to be U. S.
Gov't issue metal) then gave it a good spin about the time she sat
down. Class dismissed!
On Mon, 1 Dec 2003 22:02:33 UTC "CRWLR" <beerman@yahoo.com> wrote:
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
>
>
>
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/
>
--
Will Honea <whonea@codenet.net>
independantly and one at a time - part of the pre=flight is to switch
mags and watch for an RPM drop. I was damned glad to have mag
ingintion a couple of times when the rest of the electrical system
went AWOL on me <g>.
Best use I ever saw for a suplus C-47 magneto was the one somebody
hooked up to a young female teacher's chair (which happend to be U. S.
Gov't issue metal) then gave it a good spin about the time she sat
down. Class dismissed!
On Mon, 1 Dec 2003 22:02:33 UTC "CRWLR" <beerman@yahoo.com> wrote:
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
>
>
>
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/
>
--
Will Honea <whonea@codenet.net>
#56
Guest
Posts: n/a
Re: Magneto
"Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
news:20031201180016322-0900@news.newsguy.com...
> On 01 Dec 2003 01:02 PM, CRWLR posted the following:
> > My lawn mower has a magneto and has no battery or alternator. The
> > magneto replaces the ignition system, not the charging system. It also
> > is a magnetic device not a points-based device as another poster
> > suggested -- perhaps the powerful magnet is the basis for the name,
> > magneto. The large magnet whirling around the pick up is what creates
> > the electrical pulse needed for the ignition, not opening and closing
> > points.
>
> That's the point. If your lawnmower had an automotive type ignition
> system, it would need a battery and alternator or generator to run. The
> magneto doesn't replace the battery or alternator for engine starting or
> running accessories, but it does eliminate the need for a charging
> system with regard to the ignition. An airplane can suffer a total
> electrical system failure (as I did one day) and the engine keeps firing
> just fine.
>
I can go along with that. The magneto is the charging system (battery and
alternator) and ignition system, all rolled into one. It that respect, it
replaces the battery and alternator.
> The magneto does use points and the timing of the points is critical to
> the operation of the mag. All the magnet does is generate electrical
> current, and the pulse is generated by the opening of the points which
> interrupts current in the primary windings of the coil. This causes the
> magnetic field which was induced in the primary windings to collapse,
> which in turn induces a high voltage current in the secondary windings.
> It is the current induced in the secondary windings of the coil which
> are sent to the plugs via the distributor. A magneto is really just a
> self-contained system which includes the generator, points, coil, and
> distributor all in one handy package. I can post a schematic if you'd
> like, since I took a test on aircraft ignition systems a few weeks ago
> and still have textbooks and stuff laying around (I'm about 6 months
> away from having my A&P mechanic's certificate).
>
The magneto systems that I have played with were very rudementry, and they
were simply an induction coil thingie that was set off by the large magnet
flying by that was embedded into a huge chunk of metal. I can see where an
aircraft might use a considerably more sophisticated system that actually
employed points and other hardware.
> > I have never seen a magneto system that uses any sort of advance. but
> > this could be acheived relatively easily. All that is needed is to
> > mount the pick up on a plate that rotates around the crank shaft. Then,
> > all that would be required is a means of moving this plate a few
> > degrees when it was desired. Like I said, I have not seen this sort of
> > thing, but it shouldn't be impossible to acheive.
>
> It isn't done simply because mags are mostly used in aircraft these days,
> which run for hours on end in the same narrow range of RPM and power
> output (the same could be said for your mower). The timing can be fixed
> at the optimal setting for these conditions, so there isn't much to be
> gained by a variable advance mechanism and it would be just one more
> thing to fail.
>
Do you have a manual control on the magneto that you can trim the timing for
optimal performance? For instance, we once had a manual choke on our
carburators that Grandpa had to play with to get the motor to even run. I
seem to remember that Grandpa's first car might have had a magneto to adjust
too. It would have been a similar sort of mechanical thingie as the choke,
but maybe it was mounted in the center of the steering wheel.
I would think that a similar sort of thing might be useful to trim the mags
for different kinds of engine operation. I understand that the plane engine
will run for hours on end at a fixed speed, but I was thinking that taxiing
at 2500 rpm might demand a different mag setting than sustained flight at
80% of capacity. I assume that crusing speed is somewhere around 80%, and
that 100% would be reserved for take off and maybe climbing steeply.
> > I think the largest
> > problem to solve in the magneto system is the length of time it takes
> > to build enough charge to give a powerful spark. I am not positive,
> > but I think part of the reason that airplanes have two magnetos is
> > that they are on half cycle duty cycle. That is, they fire alternately
> > so that they get a rest between firings. Admittedly, that is a SWAG,
> > but I thought I would throw it out anyway.
>
> That is incorrect. Both mags fire each cylinder simultaneously (two
> plugs per cylinder).
>
> > Airplanes could use two
> > just so that there is a back up system in case the primary ignitin
> > system fails. A plane, after all, has considerable safety problems
> > when the motor quits running, all that happens to a car is that it
> > rolls to the side of the road.
>
> The most often quoted reason for two mags is reliability as you mention,
> but that is followed with "oh by the way" the engine won't run right or
> make anywhere near full power on just one mag. This is because aircraft
> engines typically have huge pistons and the flame front won't propogate
> correctly without both spark plugs firing. In most cases the loss of a
> mag should allow you to limp home but if you are heavy or at a high
> density altitude that is by no means certain. It may mean that you just
> have more time to choose the crash site.
>
> > An automobile has space constraints that would prohibit the
> > application of a magneto,
>
> You should try working on an airplane sometime. 8^P
>
Doesn't the magneto add a ---- load of weight to the crankshaft? I always
thought that my lawnmower took so long to shut down was because the flywheel
(where the magneto's magnets are located) was so damn heavy. Of course, the
single jug will take a long time to stop the motor too, where a multi-jug
motor will have more opportunities to arrest the speeding flywheel with
additional compression strokes ...
#57
Guest
Posts: n/a
Re: Magneto
"Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
news:20031201180016322-0900@news.newsguy.com...
> On 01 Dec 2003 01:02 PM, CRWLR posted the following:
> > My lawn mower has a magneto and has no battery or alternator. The
> > magneto replaces the ignition system, not the charging system. It also
> > is a magnetic device not a points-based device as another poster
> > suggested -- perhaps the powerful magnet is the basis for the name,
> > magneto. The large magnet whirling around the pick up is what creates
> > the electrical pulse needed for the ignition, not opening and closing
> > points.
>
> That's the point. If your lawnmower had an automotive type ignition
> system, it would need a battery and alternator or generator to run. The
> magneto doesn't replace the battery or alternator for engine starting or
> running accessories, but it does eliminate the need for a charging
> system with regard to the ignition. An airplane can suffer a total
> electrical system failure (as I did one day) and the engine keeps firing
> just fine.
>
I can go along with that. The magneto is the charging system (battery and
alternator) and ignition system, all rolled into one. It that respect, it
replaces the battery and alternator.
> The magneto does use points and the timing of the points is critical to
> the operation of the mag. All the magnet does is generate electrical
> current, and the pulse is generated by the opening of the points which
> interrupts current in the primary windings of the coil. This causes the
> magnetic field which was induced in the primary windings to collapse,
> which in turn induces a high voltage current in the secondary windings.
> It is the current induced in the secondary windings of the coil which
> are sent to the plugs via the distributor. A magneto is really just a
> self-contained system which includes the generator, points, coil, and
> distributor all in one handy package. I can post a schematic if you'd
> like, since I took a test on aircraft ignition systems a few weeks ago
> and still have textbooks and stuff laying around (I'm about 6 months
> away from having my A&P mechanic's certificate).
>
The magneto systems that I have played with were very rudementry, and they
were simply an induction coil thingie that was set off by the large magnet
flying by that was embedded into a huge chunk of metal. I can see where an
aircraft might use a considerably more sophisticated system that actually
employed points and other hardware.
> > I have never seen a magneto system that uses any sort of advance. but
> > this could be acheived relatively easily. All that is needed is to
> > mount the pick up on a plate that rotates around the crank shaft. Then,
> > all that would be required is a means of moving this plate a few
> > degrees when it was desired. Like I said, I have not seen this sort of
> > thing, but it shouldn't be impossible to acheive.
>
> It isn't done simply because mags are mostly used in aircraft these days,
> which run for hours on end in the same narrow range of RPM and power
> output (the same could be said for your mower). The timing can be fixed
> at the optimal setting for these conditions, so there isn't much to be
> gained by a variable advance mechanism and it would be just one more
> thing to fail.
>
Do you have a manual control on the magneto that you can trim the timing for
optimal performance? For instance, we once had a manual choke on our
carburators that Grandpa had to play with to get the motor to even run. I
seem to remember that Grandpa's first car might have had a magneto to adjust
too. It would have been a similar sort of mechanical thingie as the choke,
but maybe it was mounted in the center of the steering wheel.
I would think that a similar sort of thing might be useful to trim the mags
for different kinds of engine operation. I understand that the plane engine
will run for hours on end at a fixed speed, but I was thinking that taxiing
at 2500 rpm might demand a different mag setting than sustained flight at
80% of capacity. I assume that crusing speed is somewhere around 80%, and
that 100% would be reserved for take off and maybe climbing steeply.
> > I think the largest
> > problem to solve in the magneto system is the length of time it takes
> > to build enough charge to give a powerful spark. I am not positive,
> > but I think part of the reason that airplanes have two magnetos is
> > that they are on half cycle duty cycle. That is, they fire alternately
> > so that they get a rest between firings. Admittedly, that is a SWAG,
> > but I thought I would throw it out anyway.
>
> That is incorrect. Both mags fire each cylinder simultaneously (two
> plugs per cylinder).
>
> > Airplanes could use two
> > just so that there is a back up system in case the primary ignitin
> > system fails. A plane, after all, has considerable safety problems
> > when the motor quits running, all that happens to a car is that it
> > rolls to the side of the road.
>
> The most often quoted reason for two mags is reliability as you mention,
> but that is followed with "oh by the way" the engine won't run right or
> make anywhere near full power on just one mag. This is because aircraft
> engines typically have huge pistons and the flame front won't propogate
> correctly without both spark plugs firing. In most cases the loss of a
> mag should allow you to limp home but if you are heavy or at a high
> density altitude that is by no means certain. It may mean that you just
> have more time to choose the crash site.
>
> > An automobile has space constraints that would prohibit the
> > application of a magneto,
>
> You should try working on an airplane sometime. 8^P
>
Doesn't the magneto add a ---- load of weight to the crankshaft? I always
thought that my lawnmower took so long to shut down was because the flywheel
(where the magneto's magnets are located) was so damn heavy. Of course, the
single jug will take a long time to stop the motor too, where a multi-jug
motor will have more opportunities to arrest the speeding flywheel with
additional compression strokes ...
#58
Guest
Posts: n/a
Re: Magneto
"Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
news:20031201180016322-0900@news.newsguy.com...
> On 01 Dec 2003 01:02 PM, CRWLR posted the following:
> > My lawn mower has a magneto and has no battery or alternator. The
> > magneto replaces the ignition system, not the charging system. It also
> > is a magnetic device not a points-based device as another poster
> > suggested -- perhaps the powerful magnet is the basis for the name,
> > magneto. The large magnet whirling around the pick up is what creates
> > the electrical pulse needed for the ignition, not opening and closing
> > points.
>
> That's the point. If your lawnmower had an automotive type ignition
> system, it would need a battery and alternator or generator to run. The
> magneto doesn't replace the battery or alternator for engine starting or
> running accessories, but it does eliminate the need for a charging
> system with regard to the ignition. An airplane can suffer a total
> electrical system failure (as I did one day) and the engine keeps firing
> just fine.
>
I can go along with that. The magneto is the charging system (battery and
alternator) and ignition system, all rolled into one. It that respect, it
replaces the battery and alternator.
> The magneto does use points and the timing of the points is critical to
> the operation of the mag. All the magnet does is generate electrical
> current, and the pulse is generated by the opening of the points which
> interrupts current in the primary windings of the coil. This causes the
> magnetic field which was induced in the primary windings to collapse,
> which in turn induces a high voltage current in the secondary windings.
> It is the current induced in the secondary windings of the coil which
> are sent to the plugs via the distributor. A magneto is really just a
> self-contained system which includes the generator, points, coil, and
> distributor all in one handy package. I can post a schematic if you'd
> like, since I took a test on aircraft ignition systems a few weeks ago
> and still have textbooks and stuff laying around (I'm about 6 months
> away from having my A&P mechanic's certificate).
>
The magneto systems that I have played with were very rudementry, and they
were simply an induction coil thingie that was set off by the large magnet
flying by that was embedded into a huge chunk of metal. I can see where an
aircraft might use a considerably more sophisticated system that actually
employed points and other hardware.
> > I have never seen a magneto system that uses any sort of advance. but
> > this could be acheived relatively easily. All that is needed is to
> > mount the pick up on a plate that rotates around the crank shaft. Then,
> > all that would be required is a means of moving this plate a few
> > degrees when it was desired. Like I said, I have not seen this sort of
> > thing, but it shouldn't be impossible to acheive.
>
> It isn't done simply because mags are mostly used in aircraft these days,
> which run for hours on end in the same narrow range of RPM and power
> output (the same could be said for your mower). The timing can be fixed
> at the optimal setting for these conditions, so there isn't much to be
> gained by a variable advance mechanism and it would be just one more
> thing to fail.
>
Do you have a manual control on the magneto that you can trim the timing for
optimal performance? For instance, we once had a manual choke on our
carburators that Grandpa had to play with to get the motor to even run. I
seem to remember that Grandpa's first car might have had a magneto to adjust
too. It would have been a similar sort of mechanical thingie as the choke,
but maybe it was mounted in the center of the steering wheel.
I would think that a similar sort of thing might be useful to trim the mags
for different kinds of engine operation. I understand that the plane engine
will run for hours on end at a fixed speed, but I was thinking that taxiing
at 2500 rpm might demand a different mag setting than sustained flight at
80% of capacity. I assume that crusing speed is somewhere around 80%, and
that 100% would be reserved for take off and maybe climbing steeply.
> > I think the largest
> > problem to solve in the magneto system is the length of time it takes
> > to build enough charge to give a powerful spark. I am not positive,
> > but I think part of the reason that airplanes have two magnetos is
> > that they are on half cycle duty cycle. That is, they fire alternately
> > so that they get a rest between firings. Admittedly, that is a SWAG,
> > but I thought I would throw it out anyway.
>
> That is incorrect. Both mags fire each cylinder simultaneously (two
> plugs per cylinder).
>
> > Airplanes could use two
> > just so that there is a back up system in case the primary ignitin
> > system fails. A plane, after all, has considerable safety problems
> > when the motor quits running, all that happens to a car is that it
> > rolls to the side of the road.
>
> The most often quoted reason for two mags is reliability as you mention,
> but that is followed with "oh by the way" the engine won't run right or
> make anywhere near full power on just one mag. This is because aircraft
> engines typically have huge pistons and the flame front won't propogate
> correctly without both spark plugs firing. In most cases the loss of a
> mag should allow you to limp home but if you are heavy or at a high
> density altitude that is by no means certain. It may mean that you just
> have more time to choose the crash site.
>
> > An automobile has space constraints that would prohibit the
> > application of a magneto,
>
> You should try working on an airplane sometime. 8^P
>
Doesn't the magneto add a ---- load of weight to the crankshaft? I always
thought that my lawnmower took so long to shut down was because the flywheel
(where the magneto's magnets are located) was so damn heavy. Of course, the
single jug will take a long time to stop the motor too, where a multi-jug
motor will have more opportunities to arrest the speeding flywheel with
additional compression strokes ...
#59
Guest
Posts: n/a
Re: Magneto
On small bikes, the magneto also powers up the lights and horn. The
headlight dims radically at idle and you can pop bulbs at high speeds if
the engine is 'tweaked' to give more than stock rpm.
Anyone running a magneto system carries extra bulbs, the power with rpm
changes cook them fast, same for spark plugs ant the plug wire caps.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
CRWLR wrote:
>
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/
headlight dims radically at idle and you can pop bulbs at high speeds if
the engine is 'tweaked' to give more than stock rpm.
Anyone running a magneto system carries extra bulbs, the power with rpm
changes cook them fast, same for spark plugs ant the plug wire caps.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
CRWLR wrote:
>
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/
#60
Guest
Posts: n/a
Re: Magneto
On small bikes, the magneto also powers up the lights and horn. The
headlight dims radically at idle and you can pop bulbs at high speeds if
the engine is 'tweaked' to give more than stock rpm.
Anyone running a magneto system carries extra bulbs, the power with rpm
changes cook them fast, same for spark plugs ant the plug wire caps.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
CRWLR wrote:
>
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/
headlight dims radically at idle and you can pop bulbs at high speeds if
the engine is 'tweaked' to give more than stock rpm.
Anyone running a magneto system carries extra bulbs, the power with rpm
changes cook them fast, same for spark plugs ant the plug wire caps.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
CRWLR wrote:
>
> My lawn mower has a magneto and has no battery or alternator. The magneto
> replaces the ignition system, not the charging system. It also is a magnetic
> device not a points-based device as another poster suggested -- perhaps the
> powerful magnet is the basis for the name, magneto. The large magnet
> whirling around the pick up is what creates the electrical pulse needed for
> the ignition, not opening and closing points.
>
> I have never seen a magneto system that uses any sort of advance. but this
> could be acheived relatively easily. All that is needed is to mount the pick
> up on a plate that rotates around the crank shaft. Then, all that would be
> required is a means of moving this plate a few degrees when it was desired.
> Like I said, I have not seen this sort of thing, but it shouldn't be
> impossible to acheive. I think the largest problem to solve in the magneto
> system is the length of time it takes to build enough charge to give a
> powerful spark. I am not positive, but I think part of the reason that
> airplanes have two magnetos is that they are on half cycle duty cycle. That
> is, they fire alternately so that they get a rest between firings.
> Admittedly, that is a SWAG, but I thought I would throw it out anyway.
> Airplanes could use two just so that there is a back up system in case the
> primary ignitin system fails. A plane, after all, has considerable safety
> problems when the motor quits running, all that happens to a car is that it
> rolls to the side of the road.
>
> An automobile has space constraints that would prohibit the application of a
> magneto, and one would still need the alternator to power the other
> electrical systems on board. It makes more sense from a design perspective
> to use the charging system to set up the electrical pulse needed to get the
> spark, then use a timing system to provide the spark at the correct instant.
>
> "Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
> news:20031129225538908-0900@news.newsguy.com...
> > On 29 Nov 2003 07:17 PM, c posted the following:
> > >
> > >
> > > "Kevin" <Kevin@el.net> wrote in message
> > > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> > >> Is a magneto ignition system more reliable than the alternators used
> > >> on cars? Can you use mags on a jeep ?
> > >>
> > >
> > > A magneto doesn't replace an alternator, it replaces the distributor.
> > > Even with a magneto ignition, you'll still need your charging system.
> > > Magnetos use points. they are not as reliable as an electronic
> > > ignition.
> >
> > From the standpoint of ignition, the magneto does replace the alternator
> > and battery, since the mag generates its own power. You will
> > undoubtedly still want the alternator and battery to get the thing
> > started and to run electrical accessories. As for reliability, the
> > magneto doesn't have to be more reliable than the electronic ignition,
> > it only has to be more reliable than the battery and its charging system.
> > Other than lack of self-generating ability, the electronic ignition is
> > better in every way.
> >
> > > Also, most of them don't have a mechanical advance, and none
> > > I know of has a vacuum advance. This means your timing will not be
> > > optimized for light load conditions with the vacuum advance. You can
> > > use a magneto on anything they make magnetos for.
> >
> > This is true.
> >
> > ----------------------------------------------------
> > Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> > Remove _kills_spammers_ to reply via email.
> > Unofficial Bearhawk FAQ website:
> > http://www.rawlinsbrothers.org/bhfaq/