Spaceworm and Jedijody, thank you for your helpful replies to my request for tips on how fix and engine that refuses to shut down even though the throttle is fully closed. Your refraining from wise cracks and ridicule was appreciated.

I can candidly say that I've never, ever, had that problem. Even with weedeater conversions and an RCGF 26. If I had an engine that would not shut down with the idle trim I'd be doing some investigation and probably some repair work. It sure would not go to the field that way. Perhaps a different carb?

If the power is not interrupted but the signal is the engine cut doesn't work. If the failsafe isn't programmed for idle RPM in the evnt of signal loss the throttle may remain at any throttle setting while the ignition cut remains asleep. Likely the throttle will remain at the position last used. Plan for the worst in those events. Set up the failsafe for an idle or idle cut off. Set up the engine itself where it can be manually shut down with the idle trim lever. If that can't be done, fix the engine. If you install an ignition kill do not use that as the primary means of engine cut off. It's still an additional safety device. Anything electrical, or mechanical, can fail. A very good reason to never, ever, remove the throttle return springs from a carb. They work real well if the linkage fails.

Thank you too, Tired Old Man.

Sorry if I missed it here in the thread, but another alternative exists... putting a servo on the choke and using the choke to, well, choke the engine. I have put it on my latest DLE55 engine... I had an old servo laying around... works fine.

I have had the runaway bird situation before, the idle changed as the engine warmed up in the air and it was impossible to land. I solved it by removing the low idle restriction SCREW from the engine and setting throttle servo end points to allow killing engine with the throttle. I am very careful now with throttle setup before flying. I do not see how it is possible for an engine to continue running when the throttle is fully closed. My problem was the screw prevented it and left a small air opening.

I don't have any ignition kill switches, but have considered getting them. This discussion will have influenced that decision. I like to fly as safely as possible, but I do not wear a belt and suspenders either.

OK i know we all realize the safety issues that were somewhat ignored in the video, but this one has to take the cake...........in this case a gun to shoot this retard would have been appropriate. (video is of a DR1 landing and)

http://www.youtube.com/watch?v=Qao_W...eature=related

I have never seen anything remotely as (insert comment here) stupid, stupid , stupid.
John

So, what'd you do?
Get rid of the (electronic) ignition (kill) switch and rig a manual throttle override(trim) lever so's when you let off the gas at the end of a drive, the engine dies?
Ingenious.

Lucky you. Anyway, I'm going to dig into my P-51/RCGF 26 that I've been unfortunate enough to have not shutdown with the idle trim and see if I can fix it. I suppose we can agree that yes, it would not be prudent to take it to the field until this is solved.

I have a G-38 that was on a Giant Super sportster that lost the muffler when I was flying due to vibration. After the muffler came off, with no back-pressure on the engine, I couldn't get it to idle down (I set all my planes up so I can use the throttle trim to kill the engine), even with the trim all the way down. So I circled around, and killed the engine with the remote switch. I have a simple set-up to do this, as I mounted a radio-shack switch (cheap) to the side of a servo, and one of the big round servo wheels on the servo (it looks like a cam of sorts), all set up on my gear switch so when I flip the switch, it rotates the "cam", flips the switch, and grounds out the magneto. Its a simple setup that works fine, and even though I use it as my main kill switch (in addition to my outboard mounted grounding kill switch, and my throttle setup), so I have 3 potential ways to kill the engine. I do that with all of my gassers now.

Dave

In the early '60s, Dulles Airport outside DC had been abandoned before completion.
2 mile long runways in several directions!
Flew r/c from there a few times, and then they decided to finish it.
Drat!

.
I wanna see the video by the hittee!

I have also had mufflers come loose and not be able to get a low enough idle trim to perform a proper landing! I would in turn line the plane up on a decent approach and flip the gear switch which inturn would close the choke and float on in to a dead stick landing! I don't have any warbirds and am a 3-d weirdo so the gear switch becomes the choke switch. I also like to watch the other pilots look of amasement when I can start a cold engine up with one flip by releasing the choke as soon as the engine hits and have it keep running. I look at an ignition kill switch as just another link in the chain that could possibly fail and failure is NOT an option to me! I use futaba 3004 or hitec 325 servos for the choke and are about $10 a pop which I'm sure must be much cheaper than ignition kill switch that I have never even priced!

My electric planes all have a great kill switch. It's called "the throttle" !

Do you have the radio's failsafe set so the cam operated kill switch goes to the engine kill position when you lose signal? What happens when you lose control due to battery failure, does the switch go by spring return to the kill position? Thanks for your answers.

Regards, Richard

What happens when you lose throttle control due to radio signal loss or battery failure? Thanks.

Sincerely, Richard

I always program a kill function on all my engines, nitro or gas.  When I was first trying to learn to land, my instructor taught me how to kill power om my floating trainer.  His idea wa if its set up right for the landing, kill it and land. 

But which idiot? The one kneeling down in the path of a landing model (idiot #1), or (idiot #2) the one who's model hit him?

A very wise flyer you are!

Multiple ways to kill a gasser is my preferred way too.
Safety isn't just about troubles while airborn, screw ups happen on the ground as well.

My throttle trim can kill my gassers, as well as the throttle kill switch, and then my ignition kill switch.
One, maybe two could potentially happen to fail, but one of the three is very likely to still function.

Hindsight is fine if no one got hurt or it didn't cost you big money, but doing the right thing from the start is better.
If a smart lawyer was to ever prove gross negligence, a flyer would be in deep trouble then!

I have had a brain fart or two. The most recent one I can recall is when I fired up my plane and had the Rx on, but forgot to turn on the Tx (I know, duh......I am sure I will hear it about this one). The plane fired up at about half throttle, and leaped forward. Of course, I could kill it easily with the external switch, but it certainly got my attention. I did, of course, have my plane properly restrained before I started it up, so it didn't go far, but here is another case of following safety protocol paid off, with both the external switch, and the tail restraint.

Dave

No, but its an interesting thought. I take the spring off of my gassers. I could be wrong, but have you ever tried to move a servo by hand when there is no power applied? I would have to think that if I lost power, it would take a pretty strong spring to pull that servo back to the idle position, and with that much force pulling on my servo all the time, it seems like a lot of current drain for a servo to have to exert whenever i have my plane on. As far as battery failure goes, I don't have a plan for that one. But I probably should. Everything would just stay in the position it was in when the battery failure occured. I think that redundant battery power is the best backup for this, but for all-out failure, no, it doesn't kill the engine the way I have it set up. I would have to think about how I would want the system to react in that case too. I have never had a battery failure that I am aware of, and with 2.4, I am less worried about signal. But you can only prepare for so many situations

But, aren't all of these three dependent on a functioning radio? Isn't the throttle trim the same as throttle cut, just activated by the throttle trim or the cut switch? Or, is one or more actuated by loss of battery power or signal? Recently a friend killed his engine with the throttle cut, then as the plane landed he turned the throttle cut switch back to run, which WAS his practice. The dead engine fired right back up and clipped another fliers plane before it was stopped. Apparently the piston stopped just after TDC and the still energized electronic CDI fired the residual fuel in the cylinder as soon as the throttle cut switch was turned off and the throttle was advanced to the idle position. A rare but actual experience. He now leaves the throttle cut switch in the cut position and also insures that the throttle stick is all the way down to idle after he lands. He then immediately turns off the ignition battery and the receiver battery switches before turning off his transmitter, and returning to the pits.

Regards, Richard

Good point. Multiple redundancy with a single point of failure, huh ?
Here is one not dependent on the radio ..... a loaded shotgun next to the pilot

I always setup the failsafe's, but forget to mention them.

Failsafe sets throttle to idle.
Failsafe kills the optical ignition
Loss of signal kills the optical ignition.
Shutting the Tx OFF kills the optical ignition.

On most of my gassers I use Hitech servos, and that gives me yet another
way to take advantage of 'failsafe'. With their programmer, many Hitec
servos can be independently set to a 'failsafe' mode.

With my gassers properly setup, do I really need an optical ignition kill system?
Probably not.

Do I want such? Most certainly! It gives me a dead nuts, sure fire means of
cutting power to the ignition, remotely so. No power=no ignition=dead/off engine!

As far as functioning TX goes; if not, what good will a choke servo do ya?

We had a incident on a 2.2 mtr 540 Edge where the throtle servo broke loose ( Sure the spinner came loose) she was at WOT, Fortunately the pilot was experienced and did some tight banks to keep the speed down. the run way is very short. the plane was fitted with a Opto kill but she came down hard breaking the firewall. My own gass bird has throtle trim kill and ignition kill. Pays to be safe in this day and age..

Lets not forget, these two idiots are $10,000 richer and on their way to $100,000 Now whos the idiots????