Magneto lesson?

[troy]

Remember, a lawnmower has mags (most everyone has operated a mower). No battery needed to continue running, just for starting. Also, the student does need to know how it works in order to better understand emergency procedures, etc. Five minutes on a mag lesson is worth it.

Quote: "We have 2 of them in case one goes out. That way, if the altenator fails, the engine continues to run" This is false, the mags and the charging circut are not connected together in any way.

 

[nosehair]

don't try to teach them how to be a mechanic!!! Teach them well, but don't waste their time and money teaching them something they don't need to know.

Nope, Dr. Pokey, can't let you spread this swill. There is much more to learning to fly than wigglin' the stick 'n passin' the checkride. If you don't care to know how the mags work - that's your business, but I, and some people, need to know this simple spark generating system to understand why the engine runs without the battery. You are right that it really can't make any difference about being able to fly the airplane, but in order to be the master of the machine, I think that a basic knowledge of how things work gives me power over the machine. Instructors should be able to explain simple mechanical concepts.

 

[Dr Pokenhiemer]

What I meant was--New students have so much information to learn, it's like drinking from a fire hose. Don't add more to it than what they can handle. I instructed for 2 years-fulltime. Some students try to make a mountain out of a molehill on some things and make it harder than it has to be. Keep it simple for them, but challenge them at the same time.

 

[nosehair]

What I meant was--New students have so much information to learn, it's like drinking from a fire hose. Don't add more to it than what they can handle. I instructed for 2 years-fulltime. Some students try to make a mountain out of a molehill on some things and make it harder than it has to be. Keep it simple for them, but challenge them at the same time.

Riiight! That is exactly true - and my little simplified explaination of how the mag makes a spark is about all I usually say about it, unless the student wants more.
You are right about some students and some instructors trying to do too much too soon.

 

[F16fixer]

O.K. thanks for corecting me on that statement! What I ment to add was that many newer vehicles have an electric fuel pump that is only run by the BATTERY. And if you unhook the battery it will shut off. Yes I have done this and that is what happens. (It has nothing to do with the alternator), but when it comes to airplanes you either have gravity fed tanks on your 152 or you have an engine driven fuel pump, so there is no reliance on a battery. This will keep the airplane running.
So why don't you go out in your drive way and unhook the battery from your CRX and see if it keeps running. If the fuel pump is directly hooked to the battery, I bet you can guess what will happen.

Oh, really? I can unhook the battery, take it in the house, and put it in my closet, and the engine keeps running. The only thing the battery in the car is needed for is starting the thing.


If I unhook the battery in the car and it shuts off, I've got an alternator problem.


I'm with Dr Pokenhiemer here. They don't need to be mechanics. The mag produces electricity for ignition as it turns. Works good, lasts long time. 'Nuf said.



.

 

[TonyC]

So why don't you go out in your drive way and unhook the battery from your CRX and see if it keeps running.

Well, for starters, I don't have a CRX in my driveway. I've never seen a component that was attached directly to a car battery which would not also be connected to the car's electrical system, powered by the alternator, were the battery cable to be disconnected from the battery. Fuel pumps are powered by alternators, too. But, I'm not an expert, and I haven't seen them all, so there could be such a system.


Nevertheless, the point of the magneto discussion is not related to fuel delivery. The point is the magneto is an independent electrical system. As long as the engine is turning, the magnetos will provide a spark.







.

 

[Stifler's Mom]

Site

Interesting website.

 

[USMCmech]

Quote: "We have 2 of them in case one goes out. That way, if the altenator fails, the engine continues to run" This is false, the mags and the charging circut are not connected together in any way.

One other thing,

Airplane engines do not need two magnetos. Some only have one, with dual distributors.

Airplane engines DO need two sparkplugs. Since the cylinder of a airplane engine is so huge the dual sparkplugs allow more complete combustion of the fuel. Combustion starts at both sides and meets in the middle. Think about it, an O-360 each cylinder has 1.5 liters of displacement in each jug. That's a lot of fuel to burn in just 12 degrees of crank rotation.


Having the second mag is just backup. Since you already have to use the dual distributors, wires, ect, why not go ahead and use an extra mag.

 

[Geronimo4497]

Having the second mag is just backup. Since you already have to use the dual distributors, wires, ect, why not go ahead and use an extra mag.

I hope that you are not bad mouthing the beautiful Bendix D-3000 dual magneto?! We won WWII with the dual mag (i.e. 1 common shaft with two "distrubutors") that was on the likes of the Corsair, P47, P51, B24/25 etc. etc. etc.

No doubt that it is more complicated than a Slick mag, however, I would argue that this magneto has recieved too much critizime for being a "piece of junk", not that I am accusing anything......

This particular style of mag is far too often the victim of "tinker-itis". Some specialized knowlege is needed to work on and service this device. I would argue that if one takes the time (no more than one weekend) to sit down with the service manual and an example of this very well enginereed magneto that vast knowlegdge can be obtained. So much, in fact, that all of your friends at the local airport will come by your hangar on the weekend and annoy you with questions about proper mag timing!!!!

I do not have an airplane that has this mag installed, but have been fortunate enough to work on several airplanes with this type of mag (172N, 182RG).

If you have the burning desire to 'know all there is to know' about basic a/c engine systems, checkout http://www.avweb.com/sponsors/skyranch/index.htm.

I'm not affiliated with skyranch, just impressed by the info that has been compilied on the CD.

Off to go admire my Bendix S-200 starting vibrator mags now........


By the way, throw away any Slick mag you see, I would be very greatful!

 

[Balou]

It goes spinny and makes sparky

Laughed my a** off, mind if I use that one in the future ?

 

[TrafficInSight]

Laughed my a** off, mind if I use that one in the future ?

not at all