andernamen

My Feedback: (3)

I have a TF Giant Mustang with a 45cc conversion engine. I have a mechanical switch on the side of the airplane that kills the magneto and stops the engine. I have the throttle set up like a glow engine so that when I bring the throttle all the way down, the engine will die. I only have a six channel radio and all are in use. Is there a way to set up a kill switch that works with my throttle servo to ground the magneto?

apalsson

My Feedback: (1)

Have you considered a microswitch that gets activated by the throttle servo?
When you bring the throttle trip all the way down, the servo activates the microswitch to ground the magneto

karolh

You can use a Y connector in the channel for the Rx battery, then use one end for the battery and the other for an electronic Tx operated kill switch.

Karol

andernamen

My Feedback: (3)

Not sure about the Y connector, as I only have a 6-channel transmitter. The receiver has eight channels. I was thinking about a micro switch, and that is likely what I'll do. Thanks.

captinjohn

Have a person with you that has a 12 gauge shotgun...If the airplane makes a bad move...SHOOT IT!!!!

scale only 4 me

My Feedback: (158)

Theoretically yes, but the mechanical linkage would have to be adjusted just right, Y of the throttle channel to a small or micro servo that operates the kill to ground switch,, then you need to adjust it so it kills the mag at the same time your throttle trim is all the way down while at the same time being open at an reasonably low idle so you can taxi.

Truthfully,,
if you're going to be into Giant Scale and are *****g out your TX,, it's time to upgrade to a 8 or 10 channel computer radio,,

good luck

beepee

ander,

Most of my setups are like yours, without the additional kill. If your throttle will reliably kill the engine, you have the basics. A limit switch operated by the throttle servo is only half protection (not bad, but not all the way there). If you have a throttle servo failure you are still out of luck. You can y-harness to a separate servo operated by the throttle channel to solve that one. As pointed out by others, the better solution is a separate channel, but you don't have to rush into that one. I flew giants only 4 channel systems for years and did not wish for the extra control. I did have a run-away throttle one time, but that was on a 6 channel system with only 4 used. I have no excuse for not having a kill available. To have done any good, though, it would have had to be on a separate channel as the throttle channel was useless during the failure.

Bedford

andernamen

My Feedback: (3)

Agree with all, including upgrading the radio. Just can't spend the money right now. I like the Y to the throttle servo, then using this to operate a micro swich. I'll try that. As for leaving it as is, the AMA I believe requires the plane to be shut off with the radio. I think the switch would qualify.

beepee

Your plan is sound, but your arrangement as it is complies with AMA requirements. "Shut-off of the engine with the radio" can be done by the throttle servo control of the carb.

Make sure your switch and servo activation system are good and solid. When I have installed such an arrangement they have become unreliable after a time.

Bedford

scale only 4 me

My Feedback: (158)

I've used my kill switches to land my gassers before many times. Just last week actually when my P-47 throttle linkage came loose and jambed so I couldn't bring it down under half throttle.

I remember back in the Day,, early days of giant scale and big gassers,, a guy brought out a 33% extra, I think it was a lanier w/ a Quadra/Arrow 100,, Maiden flight he's tooling around and the plane goes full throttle and he has no throttle control. As he's flying high waiting for the thing to run out of fuel, the access hatch blows off,, a few seconds later the whole back of the fuse explodes from the air pressure entering. Death spiral to balsa/foam dust and what a dent it made in the ground

A little extra work and a $25 servo/switch could have possibly prevented it all,, I wouldn't take one up without it

Edwin

My Feedback: (2)

Another thing to consider, the size of your fuel tank. Lots of people go big with about 30 minutes of fuel. I size my tanks for 12 to 13 minute flights if I can. I've seen batteries give out before fuel runs out.
Edwin