finaly

[canadianhorsepower]

I've ordered a book like 6 weeks ago and today hurray
it arrive
the picture says it all.
almost read it all today
Thanks Bob Shores

 

[Lakc]

Ah, the story of electricity and his wife.

 

[Paulsv]

I'm tempted to get that book, but I'm pretty much a dunce when it comes to electricity, so it would probably be over my head.

I've always thought it would be cool to incorporate a magneto system into a model engine with a flywheel, like, say, a Webster, to make it a stand-alone engine, rather than having to hook up battery, coil, etc. Perhaps mount the magnets on the flywheel, and kind of hide the magneto under the flywheel, and mostly hidden in the base. It seems like you ought to be able to do it with a magneto from a chainsaw or weed whacker engine.

 

[///]

Thanks for the reminder!
I could have sworn I had ordered this book, still hasn't arrived.
Think I need to check my Credit Card and Paypal history

 

[AussieJimG]

Paulsv, I agree; it would be good to have the ignition integrated into the machine. I will follow this thread to see if someone can suggest a way.

Jim

 

[canadianhorsepower]

Paulsv, I agree; it would be good to have the ignition integrated into the machine. I will follow this thread to see if someone can suggest a way.

Jim

Paulsv and Jim
I was surprise how lo down to basic step by step procedures
are include in the book on "how to" make coils and magneto's. I ordered it from "Plough Book Sales" they only had 3 left and I was told they won't re-print it

 

[johnny1320]

I just placed my order, can't have too many books

 

[Lew Hartswick]

I've always thought it would be cool to incorporate a magneto system into a model engine with a flywheel, like, say, a Webster, to make it a stand-alone engine, rather than having to hook up battery, coil, etc. Perhaps mount the magnets on the flywheel, and kind of hide the magneto under the flywheel, and mostly hidden in the base. It seems like you ought to be able to do it with a magneto from a chainsaw or weed whacker engine.

The problem you'll run into very quick is, the magnet must be moving past the coil at a
high speed. On Model engines the size reduction makes that, if not impossible almost so. Both size and, usually, slower RPM. IF youre model runs as fast as a chain saw
will probably work just fine.
...lew...

 

[Paulsv]

The problem you'll run into very quick is, the magnet must be moving past the coil at a
high speed. On Model engines the size reduction makes that, if not impossible almost so. Both size and, usually, slower RPM. IF youre model runs as fast as a chain saw
will probably work just fine.
...lew...

Well, I was thinking that an engine like the Webster, with a 3 and 3/4" flywheel, probably has a bigger flywheel than my weed whacker or chainsaw motor. And the magneto gives spark when you pull start it, which can't be a very high RPM. But the two stroke on the chain saw or weed wacker probably idles pretty fast, compared to a Webster, and they don't run as smoothly at idle as at higher RPM's, which might be because of a weaker spark at low RPM's, I guess. Another difference is that the weed whacker and chain saw are two stroke motors, so you get a spark on every revolution, while the Webster is a four stroke. I guess you could just have a waste spark on the exhaust stroke. On the other hand, there are four stroke lawnmowers that use magneto ignition, so there must be a way to do it. It would be kind of cool if you could just buy a magneto ignition module of the shelf and adapt it for a model engine.

 

[AussieJimG]

To get the magnet speed, perhaps we need to consider an impulse magneto or something similar where the magnet is drawn back and then flicked past the coil by a spring.

Jim

 

[canadianhorsepower]

To get the magnet speed, perhaps we need to consider an impulse magneto or something similar where the magnet is drawn back and then flicked past the coil by a spring.

Jim

You can spin a magneto at 20 RPM and it will spark

I did try it. I'm in the process of trying something
similar for my next Webster and so far it's going fine
all the way

 

[Paulsv]

There was someone on this board that did a Webster with a MiniMag Magneto, but it is a stand-alone magneto that was belt driven. Member Blue Rock was building one, but the last post was April 9, 2011.

http://www.homemodelenginemachinist.com/f31/yet-another-webster-15179/

 

[Paulsv]

Hey Luc- your spelling has improved considerably. It's better than mine now!

 

[Paulsv]

To get the magnet speed, perhaps we need to consider an impulse magneto or something similar where the magnet is drawn back and then flicked past the coil by a spring.

Jim

Interesting idea. I can imagine some wear problems with the spring and the mechanism that flicks the magneto, if you go that route, so it would be nice if the magneto worked at the necessary RPM for a Webster. I have to finish building the Webster before I can start playing with it tho. Unfortunately, machining is a winter hobby for me. During the summer I'm out of town most weekends, and I don't have a lot of time in the evenings to work on it.

 

[Lakc]

Magnets have been getting stronger, even since Bob wrote that book. The corollary is we should be able to make smaller magneto's. To get them really small will likely take a whole lot of attention to flux leakage and some insanely close tolerances, along with considerable attention to primary resistance and secondary insulation.
Although magneto's are a topic of great interest of mine, enough so that I bought the book, my plate is full, so to speak. I am getting to that age where I can consider it a function of wisdom to allow others to go out and reinvent the wheel (magneto).

 

[Paulsv]

... flux leakage ...primary resistance ... secondary insulation.

I read posts like this and kind of half suspect that the poster is just making up words to pull my leg.

Although magneto's are a topic of great interest of mine, enough so that I bought the book, my plate is full, so to speak. I am getting to that age where I can consider it a function of wisdom to allow others to go out and reinvent the wheel (magneto).

I hear you. I'm getting to the age where I don't want to waste time reading something I haven't read before. I'm going to give this one a go, though.

 

[Lakc]

I read posts like this and kind of half suspect that the poster is just making up words to pull my leg.

Thanks to the back to the future franchise, anything regarding flux begins to sound suspicious, especially on the internet.

I hear you. I'm getting to the age where I don't want to waste time reading something I haven't read before. I'm going to give this one a go, though.

I have read the book, a good part of it anyway before I misplaced it here somewhere. Luc's post made me take two hours out digging through boxes in the basement thinking it might have been filed away. I bought it mostly for the theory, and was paying attention to the designs to unfold the underlying theory and methods of construction. I would recommend it to anyone. I have an ocean of fish to fry before any practical application, and then I have to find it, of course.

 

[cidrontmg]

Interesting idea. I can imagine some wear problems with the spring and the mechanism that flicks the magneto, if you go that route, so it would be nice if the magneto worked at the necessary RPM for a Webster. I have to finish building the Webster before I can start playing with it tho.

There's "Building the Minimag", by Bogstandard, see the last video below, http://www.modelenginemaker.com/index.php/topic,356.msg2780.html#msg2780
You can see a Webster engine chunking with the Minimag magneto. Incidentally, I built a Minimag, and am building (slowly!) another Webster. I have an Ariel 500cc bike, -58 vintage, cobbled to the Minimag. Makes a very powerful spark, the original Lucas magneto is rather weak and unreliable.

 

[ShedBoy]

The problem you'll run into very quick is, the magnet must be moving past the coil at a
high speed. On Model engines the size reduction makes that, if not impossible almost so. Both size and, usually, slower RPM. IF youre model runs as fast as a chain saw
will probably work just fine.
...lew...

I have seen a flick magneto made from a weed eater motor and it seemed to work okay, it was on an old hit and miss engine, It was in The Old Machinery Magazine, can't find the article though.

Also remember seeing weed whacker ignition an a Webster somewhere on the web. In OZ we call them a whipper snipper for some reason.

Brock

 

[Blue_Rock]

Member Blue Rock was building one, but the last post was April 9, 2011.

http://www.homemodelenginemachinist.com/f31/yet-another-webster-15179/

Hi Paul, yes it been a while since I worked on the Webster, too many other projects had bumped it off the perch, however, I intend to finish it off in the next month or so and will resume my thread above and let you know how it goes... hopefully it will!