Question about magnetos on round engines.

gismo

gismo

Touchdown! Greaser!
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A friend has a Travel Air Biplane with a Lyc radial engine of about 200 HP. It has one dual magneto plus two distributors feeding the plugs. According to the owner (who's done a fair bit of maintenance on the airplane) there is no impulse coupler on the magneto. There is a provision for a manual spark advance control but this plane is not equipped with that. Same for a "Booster Coil" for one side of the magneto. The timing is something like 34/30 BTDC.

The question is: How does this engine start without retarding the timing? I'd think that with this much advance the thing would kick backwards the first time a cylinder fired while cranking.
 
It's equipped with auto advance built into the mag. That is how I got around putting a retard system in my F-24 / Warner 165.
 
NC19143 said:
It's equipped with auto advance built into the mag. That is how I got around putting a retard system in my F-24 / Warner 165.
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Thanks Tom. Is the advance based on RPM? Also what exactly is a "booster coil"? I'm familiar with the "Shower of Sparks" setup, is it like that or different? Would it be difficult to add and where would one find the required parts? According to the owner there is a wire and/or terminal for the "booster coil" but it's not connected.
 
You know. I think this is the first time I've ever seen Lance ask a question..
 
jesse said:
You know. I think this is the first time I've ever seen Lance ask a question..
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Well it's certainly not the first question I've asked here. Asking questions is one way to learn things.
 
lancefisher said:
Well it's certainly not the first question I've asked here. Asking questions is one way to learn things.
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I didn't mean to sound negative. I'm just used to see you responding to questions and best I can tell--always giving a really good answer.
 
jesse said:
I didn't mean to sound negative. I'm just used to see you responding to questions and best I can tell--always giving a really good answer.
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I knew what you meant, I was just pulling your chain:).
 
I happen to like Lance's answers better than his questions. C'mon, last time he asked about Bakersfield, ostensibly because of a tournament. Bakersfield!!!

But maybe he's peaked because this current question aint half bad.
 
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