[cast-away]

Hello folks,

I have a 6 channel radio and all 6 channels are in use so I am wondering of an Rcexl kill switch will still work as an isolator only in the following configuration?

LiFe battery with 2 connections, one to the receiver with an on off switch in between and the second leading to another on off switch, then the Rcexl kill switch followed by the ignition.

[cravenjw]

Sounds like you need to upgrade you radio!

Rxcel has pwm(servo) signal input. I doubt it will work on a switch with just vcc/gnd signalling.

What's you plan when your lose the throttle servo in flight. Or your idle is a bit high on landing and the plane wants to keep rolling?

[cosmith]

I second what John says above...when your done that your next upgrade will be a Tech Aero Ultra IBEC. I'm sure you can pick up a DX7/DX8 used for next to nothing.

[jtsmash]

Agree with above... however if your stuck with what you got are you able to set up the throttle to shut the engine off ? or if your using a choke servo on a switch you could just put choke on to kill the engine once you land. then you wouldn't have to bother with opto kill and an extra switch.

[JoeT]

Sharing a battery connection one to the kill and one to the receiver will not accomplish what you want to do. The RCEXL or any Kill switch needs a signal from the receiver to "turn on". Without the signal, the default is off. So unless you had a pulse generator that either puts out 1000 square waves / second your kill switch will remain in the off position.

Worse yet, if you managed to get it running, you'll be injecting ignition noise into the receiver (not good in any instance), since the isolated portion is the actual plug that goes to the receiver.

[aceplant00]

What radio do you have? What is your setup for Channels?

[cast-away]

I am using a DX6 and have flaps on the AUX channel so no room for the RCEXL. If I simply use a second battery for the ignition will there still be interference back to the receiver?

As for shutting off the engine, my plan was to set the servo to kill the engine with the throttle is at zero and of course have a kill switch back to the battery.

[JoeT]

The 2nd battery will isolate the circuit, yes. But you still have no way of keeping the RCEXL to stay on. Why complicate the installation, if I were channel limited, here's what I would do.

Instead of using an RCEXL switch, I'd grab a standard 2 position switch similar to the ones that come with your radio RX setup. Hook that up to a separate battery and go direct to the ignition feed. This will keep your ignition as a totally separate circuit from your receiver and controls. In addition it will give you a way to cut off your engine just by flipping a switch, when on the ground.

Setup your throttle so that you can cut the engine on low throttle + low trim. That way you can cut off your engine just in case.

In either case, if the throttle servo fails, you'll be flying for a long time until you run out of gas.

With a DX6, you should have enough channels though.

1 channel on Y connector for ailerons
1 Channel for rudder
1 Channel for Elevator
1 Channel for Throttle
1 For Flaps
1 For Kill switch.

[cast-away]

Thanks for the feedback Joe. I like what you are saying. I forgot to mention I have retracts on the other channel. It is a 60 size Topflite P-51D kit that I built and am adding a 20cc gas engine.

[jtsmash]

Originally Posted by JoeT

The 2nd battery will isolate the circuit, yes. But you still have no way of keeping the RCEXL to stay on. Why complicate the installation, if I were channel limited, here's what I would do.

Instead of using an RCEXL switch, I'd grab a standard 2 position switch similar to the ones that come with your radio RX setup. Hook that up to a separate battery and go direct to the ignition feed. This will keep your ignition as a totally separate circuit from your receiver and controls. In addition it will give you a way to cut off your engine just by flipping a switch, when on the ground.

Setup your throttle so that you can cut the engine on low throttle + low trim. That way you can cut off your engine just in case.

In either case, if the throttle servo fails, you'll be flying for a long time until you run out of gas.

With a DX6, you should have enough channels though.

1 channel on Y connector for ailerons
1 Channel for rudder
1 Channel for Elevator
1 Channel for Throttle
1 For Flaps
1 For Kill switch.

+1 i think the only way is to do as Joe says, battery, switch then into ignition no opto kill. Have receiver on its own battery and switch.set throttle or choke to shut engine off.