30 October 2008

Burning Questions-

We just returned from another enjoyable weekend spent with old H.S. classmates.
Saturday night, clear and chilly, was comfortably spent around a wonderful bonfire.
I made a comment that was as much a question as statement of fact, then promised myself I'd find the answer:
Wood doesn't burn.
Agree or disagree?
Look it up.

And another burning question-
I spend a great deal of time with Mr. Lycoming's product purring along behind me.
That purring is the result of some pretty violent stuff going on in that reciprocal, internal combustion engine.
Most of us have at least an idea of how that engine works, but...
When the spark plugs spark and ignite the fuel/air mixture, is that an explosion?
That fire obviously has to progress mighty quickly.
Your answer?


The Old Man said...

Wood doesn't burn, gases from the heating of the wood do.

And you bloody know that's an explosion. Look at the rates of detonation - low vs. high. You were pullin' our collective legs...

On a Wing and a Whim said...

I respectfully disagree with internal combustion being powered by explosion. It's a rate of burn, albeit very high.

Why are there two magnetos, two spark plugs per cylinder? It's not for backup - it's because with two sources of ignition, the burn is faster and more complete. Try turning off one magneto, and you'll quickly find that you're producing less power, and more likely to foul your spark plug.

Actual explosion in the cylinder is detonation, and that knocking sound can make a strong heart faint if you're 2000 AGL crossing seawater with chunks of glacier still stuck in...

Greybeard said...

THAT'S the answer I was looking for-
An explosion would definitely be indicated by expensive noises emitted by the engine...
A smooth, progressive BURN, (as indicated by the title of the post) is what we're lookin' for.

And On a wing+...
Obviously the engine works more efficiently with two separate ignition systems functioning, but we might disagree about the importance of the added safety factor, having an engine that will run on only one in an emergency.
Now, since you definitely know more about magneto ignition than I do, educate me please:
-When I turn the key to the "R" mark, am I checking the Right or Left magneto?

-Which plugs do each of the mags control?