Key Ignition vs. Toggle Switches

[av8rps]

I have two friends with Just Aircraft 912s powered Highlanders that had rough running engines that NOTHING fixed. Finally Brian from Leading Edge told one of them to get rid of that ACS switch, and like magic, the problem was cured. So my other friend did the same to his Highlander, and saw the same result.

Ironically, I purchased a Highlander last year that has a little over 200 hours on it, and it runs much rougher than does the 912ul in my Kitfox. I initially blew it off as probably being caused by my 2 blade sensenich prop, but after trying a Warp on it I got the same roughness. I haven't replaced the ACS switch yet with toggle switches, but will be doing so as my next step. Both of my buddies are insistent that is the thing to do since it did so much for their 912's.

Oh, and both of them use the ACS switch for operating the starter. They've just eliminated the mag leads from the R and L positions and replaced them with high quality toggle switches.

I can understand where an electrical engineer might not agree with the voltage statement discussed earlier in this thread. I could be wrong, but I think the problem with the ACS switch is a poor quality contact causing intermittent contact for the mags, essentially causing an erratic on-off-on-off situation for the mags (and therefore rough running engines too). I wouldn't think that would be any too good for these rather sensitve (and did I mention EXPENSIVE) 912 electronic ignition boxes.

So John and Larry, I think you are both right

[jdmcbean]

OK.. I tried staying out of this one.

We (Kitfox) and I personally have years and decades of OPERATIONAL use of the key switch. Any switch can and has failed, be it a toggle switch or a key switch. The wiring and or connector that is used is most likely the issue.

Our S-LSA aircraft use this same switch without issue and one of them is operating in a training environment with over 1400 hours in the last 2 years. Along with 1000's of other aircraft including ours personally.
I recently changed our aircraft to using toggles and a push button start because I like that setup not for any other reason.

Specifically, regardless of the style of switch the Rotax "mag" is simply going to ground. If it grounds it's off.. if it doesn't it's hot. The switch specs required according to Rotax are Min 250V .5A which the ACS switch meets.

While I personally consider LEAF and Lockwood professionals and I'm sure they have seen switch failures. I would challenge them or anyone regarding this issue. While anything can happen, it is unlikely that a switched "mag" wire to ground is going to cause a module failure.

I suspect that some may have had switch failures.. while others may have had a wire or connector issue (more likely).

On that note: We are looking at other alternatives... the ACS keyswitch is simply expensive.

[Slyfox]

good response John. I have the same thing. throw switches for the mag. there is no way I would do differently. allows me to turn the engine over with mags off. Good for many things, like getting oil pressure after oil change, making sure there is good oil pressure before the start, getting a good choke before first start. I have a key switch for starting and that switch is from 95. If that goes out I will do the push button. I have that setup on the RV and love it.

[jiott]

Could someone post a simple wiring sketch for the setup with toggle for mags and keyswitch for starting. This is probably a dumb question, but I am not very confident in electrical issues and need to start learning real soon since my panel build is coming up.

Jim

[Dorsal]

Whether you use the key for starting with switches for the mags or use the key for the mags and a push button for starting I do like having a key (that can be removed) somewhere in the system. As others have said I also like being able to turn the engine over with the mags off so I can use the Slyfox starting method among other things.

[GWright6970]

Could someone post a simple wiring sketch for the setup with toggle for mags and keyswitch for starting. This is probably a dumb question, but I am not very confident in electrical issues and need to start learning real soon since my panel build is coming up.

Jim

I wish to second Jim's request!

It would be awesome for us NON-ELECTRICAL TYPES to have a diagram showing how to incorporate the two toggle switches into the Kitfox factory diagram using the ACS switch!

I am particularly interested in how and where the shields of the two ignition wires are grounded in such an installation.

HUGE THANK YOU!
Grover