Ignition switch settings

On Mar 3, 11:09 am, "Tony Cox" wrote:
Here's a question that until yesterday I'd have thought was
obvious.

Cessna-style (and no doubt other) ignition switches have five
settings -- Off/Right/Left/Both/Start. When you're on the "Right"
setting, does it mean you are firing on the right magneto or
does it mean the right magneto is grounded?

Very good question. If we use the logic that "Both" means both magneto
circuits are open, and "Off" means both magneto circuits are closed,
that would imply that "Right" means the right magneto is open (and
hence firing).

But I am sure an A&P should be able to give a more authoritative
answer.

And I've been trying to learn for years why R is on the left and L is on the
right.

On Mar 3, 4:21 pm, "Jon Woellhaf" wrote:
And I've been trying to learn for years why R is on the left and L is on the
right.

I wonder. Maybe because the ancient systems used two toggle
switches labelled "L" and "R" and they were connected to their
respective mags. When you turned off the L switch, you were running on
the R mag. It was self-evident. Our two Citabrias still have this
setup and I bet American Champion is still building them that way.
When Bendix came up with the combination starter/mag switch, the
internal mag-shorting contacts were set up in the same order but now
they had to label them opposite so that you knew which one you were
sparking on.
I'd rather have the toggles in my Jodel but it makes the
airplane so much easier to steal. If you can get in you can go.

Dan

And I've been trying to learn for years why R is on the left and L is on
the
right.

I wonder. Maybe because the ancient systems used two toggle
switches labelled "L" and "R" and they were connected to their
respective mags. When you turned off the L switch, you were running on
the R mag. It was self-evident. Our two Citabrias still have this
setup and I bet American Champion is still building them that way.
When Bendix came up with the combination starter/mag switch, the
internal mag-shorting contacts were set up in the same order but now
they had to label them opposite so that you knew which one you were
sparking on.
I'd rather have the toggles in my Jodel but it makes the
airplane so much easier to steal. If you can get in you can go.

Very true. But I've known pilots who thought that might be very usefull if
they lost their key at a remote fishing hole...

Peter
(It is an amusing thought)

wrote

I'd rather have the toggles in my Jodel but it makes the
airplane so much easier to steal. If you can get in you can go.

You could rig up a cover to put over the toggles, with a place to put a
padlock on the cover, as long as it is not a certified plane.

Would altering a plane in that manner be against the rules for certified
planes? It would be in the certified plane's regular certified condition,
while it was being flown, after all!
--
Jim in NC

"Jon Woellhaf" wrote in message
...
And I've been trying to learn for years why R is on the left and L is on
the right.


My recollection from the last time this was discussed is that the labeles
used to be the other way around so that "L" on the left meant that the left
mag was grounded and, therefore, the right mag was firing. Then, to keep it
more consistent with the "Off" and "Both" labeling, they switched the
labeling but left the right key position which grounded the right mag so
that the left mag was firing now labeled "L"?

Doesn't bother me a bit. If one mag fails an RPM drop, I'm gonna check the
wiring to both any. What is more important to me is that the left key
position has the bottom plugs firing. That's important so that I can pull
the correct plugs the first time to clear an unusually stubborn fouling.

Say, why don't they label them "Off", "B", "T", and "Both"?
-------------------------------
Travis
Lake N3094P
PWK

"Travis Marlatte" wrote

Say, why don't they label them "Off", "B", "T", and "Both"?

Excellent suggestion! Why not? It might make too much sense, that way!

One could put an "auxiliary label" on panel next to the "L" and "R" with a
Dyno Label, or with another favorite method, though.
--
Jim in NC

"Travis Marlatte" wrote in
t:

What is more important to me is that the left
key position has the bottom plugs firing. That's important so that I
can pull the correct plugs the first time to clear an unusually
stubborn fouling.


I thought that one mag controlled the top plugs on one side and the bottom
on the other side.

On Mar 4, 12:53 am, Jackal24 wrote:
"Travis Marlatte" wrote . net:

What is more important to me is that the left
key position has the bottom plugs firing. That's important so that I
can pull the correct plugs the first time to clear an unusually
stubborn fouling.

I thought that one mag controlled the top plugs on one side and the bottom
on the other side.

Yup, on Lycoming. Continental, at least on the smaller engines,
will have the right mag firing the top plugs and the left firing the
bottom. The impulse mag (right) fires the top plugs, since they're
less likely to get wet with oil or fuel.

Dan

wrote

Yup, on Lycoming. Continental, at least on the smaller engines,
will have the right mag firing the top plugs and the left firing the
bottom. The impulse mag (right) fires the top plugs, since they're
less likely to get wet with oil or fuel.

I think you mis-interpreted his comments. He said (at least I think he
said) that one mag fires the top plugs on the left cylinders and the same
mag fires the bottom plugs on the right side cylinders.
--
Jim in NC