I have a Zenoah G45 which I have not run yet.
It has a red and black wire coming off it and I have been led to believe that this is a kill switch?

If I don`t use the kill switch should the red and black wires be connected or disconnected.

Help would be appreciated

Cheers

Malc

they have to remain unhooked if you don't want a kill switch but remember your ama insurance requires a kill switch on any gass powered model.i even run two on mine

No such rules in this country, but probably a good one.
What do you use to run the kill switch, and how do you wire it up?

Cheers

Malc

Red wire kis connected to the coil, do not remove..Ground the black wire to kill the engine...

Malc,
I'm setting up my first one but I'll elaborate on RCIGN1.
You'll find samples of kill switches at Tower.
Mine is a set of switches wire together. one is a slide switch mount thru the side of fuselage; the second one is a Normally open momentary switch activated by a lever.
These get installed away from all sevos and radio gear.
A non-metallic pushrod from a dedicated servo and channel on TX is set-up to "push" on the switch lever when you activated it via your TX.

Normally, when the two wires are connected together (coming off the engine) you are "shorting out" the ignition killing the spark to the plug.

This should answer your basic ? I'm sure if this info is incorrect someone will correct and elaborate.

I understand the need for the first switch to shut down the engine, but why the need for the micro-switch activated by a servo. Seems to be a triple redunancy if you set up your throttle servo to completely close the throttle.

Is the micro-switch an AMA requirement?

Here is a simple drawing of a kill switch setup for a magneto engine module like a G-38, G-45, or G-62.

Of course the micro switch is very desirable but optional. I personally like to use the idle stop screw because I don't want a very minor glitch stopping my engine when it is running near idle.

Ken

Here is a simple drawing of a kill switch for an external ignition module like a Brison or ZDZ.

I could not find any reference to a kill switch in the AMA Safety Code.

I did find this in the IMAA Safety Code if you are flying in an IMAA Sanctioned Event:

SECTION 5.0: EMERGENCY ENGINE SHUT OFF (Kill Switch)

5.1 Magneto spark ignition engines must have a coil-grounding switch on the aircraft to stop the engine. This will also prevent accidental starting of the engine. This switch shall be readily available to both pilot and spotter/helper. This switch is to be operated manually and without the use of the Radio System.

5.2 Engines with battery powered ignition systems must have a switch to turn off the power from the battery pack to disable the engine from firing. This will also prevent accidental starting of the engine. This switch shall be readily available to both pilot and spotter/helper. This switch shall be operated manually and without the use of the Radio System.

5.3 There must also be a means to stop the engine from the transmitter. The most common method is to close the carburetor throat completely using throttle trim, however other methods are acceptable. This requirement applies to all glow/gas ignition engines regardless of size.

Ken

chuck l
In flight any part of the Throttle linkage servo to carb connections fails (comes loose). The airflow across the carb butterfly will open it to full throttle if it has nothing holding it.
This 12# TLC constructed missile now can only be flown wide open till you run out of fuel or you nose it in for safety!

As long as the throttle linkage works properly no need for remote kill... BUT....

The reason for the transmitter controlled kill switch is a perfectly reasonable means of disabling an aircraft during any flight or ground activity. Any redundant system on these large scale aircraft make the hole hobby safer. If you are not holding your plane and the throttle sticks open and you can't chase it around. The only way you will stop it quickly is by a servo activated kill switch. Closing throttle doesn't do it quickly enough. Also having the fuselage mounted kill switch is redundant yes, but its safer. The AMA rules state you must have a kill switch on transmitter control to abide by the rules for magneto ignition systems. I also must say, Always, Always keep a fire extinguisher handy, also a AMA rule. And a good one. Fly safe and have tons of fun.