Guy's
i need help,i have a Taurus 52 with a CH ignition both new,i can't get over ten feet away from plane while it's running with out everything going nut's,that is with a Hitec 8 channel PPM rx,and when i switch to a Futaba PCM rx all is good over a 100 ft. away before it goes into failsafe.i went through everthing i could think of,there is no metal to metal any where,throttle servo is 10" away from engine and nyrod between servo and throttle arm with nylon clevis both ends.
the ground for ignition came with a eyelet that is ground to engine base bolt,does it half to be clamp to spark plug?the ignition has the rubber boot type over spark plug. there is 12" between rx, switch,battery and any ignition componets. this is the first time i had any RFI problems.
all idea's are welcome,THANKS!

1st thing I would look at if all you said is in good shape is the crital in your rx... Make sure that it is in good.. If you have anuthere rx try it.. It mite be as simple as that.. but you know how that goes

Check battery status and be sure your RX antenna wire does not run through or near any of the servo wires.

Tellspin
the PPM rx is new out of box,but i do have anothere if it comes to that.
THANKS

Inside the rubber boot that fits on your spark plug there is a metal cap the fits over the stem on the spark plug. Make sure that cap is a tight fit on the stem. Any slack there can produce a lot of RFI. If you have to squish it with the pliers but not so hard that you collapse it.
Also the stem has a button that screws on the stem. Make sure that is screwed down tight

Are you using a resistor spark plug? It should have an R in its number.
If the plug wire has a pigtail coming out of the plug wire next to the rubber cap, that should be clamped to the spark plug with a hose clamp

I'll go along with most of what Dirtybird related. The engine mounting lug may not be a good enough ground. In testing the wire polarities of the new ignition on a T-52 I noted that grounding at the engine flange bolt did not provide a good ground. That's prolly what's happening with yours. Grounding to the case directly did provide a good ground, but there is no means of attachment. You could also drill and tap a small hole in the top fin of the cylinder to attach the screw. Go slow.

Silversurfer, you have far more experience with these things than I do but maybe I can add some suggestions. I have (4) CH ignitions and they all came with very long ground leads on the spark plug cable. Being an old RF (radio) guy, I thought this looked like an antenna in the making and a source that could radiate RFI to the radio. So ... I simply shortened these leads so they would attach to a screw in a tapped hole near the spark plug. In most cases, I had to drill and tap that hole myself and I always use a crimped, not soldered HD connector as is good practice in high vibration environments. Most all of our engines have a heavy, open cooling fin on top of the cylinder that can be tapped. I prefer this method over clamping the cable to the spark plug as suggested by CH. I watched an airplane go crazy once when that hose clamp came loose so decided that method wasn't for me. I rarely see this mentioned when guys troubleshoot ignitions but it is good practice to keep all ignition connecting leads, battery or switch leads as short as possible. Bundle excess cable where necessary. It would be good for every gas RCer to see how much RFI is radiated from our ignitions. Very easily demonstrated on a spectrum analyzer. CH is very good in this regard maybe because they use shielded resistor plug cables along with resistor plugs.

Roger S.

Truckracer,

Thanks for sharing that. I'm another that does not like clamping additional items to the plug. For those that have or had the older Brison engines using CH ignitions, you may reacll that the plug leads all had that same grounding lead with the wire lug on the end. You may also recall that the head of the engine was pre-drilled and tapped by Brsion for you to attach that grounding lead. It always worked. This is the reason I suggested doing the same with the newer engines that come with the old style CH systems.

Those that have their reservations about grounding leads, clamps, or drilling and tapping a head could contact CH and order one of the newer systems with the different cap, eliminating the ground strap.

Truckracer: Thanks for the tip abot how to shorten that long lead and attach it to cylinder in a good way.....going to write that down!!!! Best Regards Capt,n

I've considered changing to the new caps but the old rubber boot system seems to work well so for. If I ever have to change a plug lead, I'd sure consider the metal cap. I sure like that system on other ignitions I own.

Ya know too, after I wrote what I did about tapping a hole, I could just see someone on here drilling a hole right into the combustion chamber ..... you know it will happen. Oh well, should make for interesting reading when they blast me for suggesting such a thing!!

R.

Like I said I do not think it will be the rx but one time I was having a big prob with my radio (new out of the box) and it would do that with the engine running.. and it was a glow engine. I sent it to D and J and he said that there was no rubber gromet under the cristil. that was the prob with it.. The vibration messed it all up..

Just takeing a stap in the dark. lol

Paul

Call TKG, get a Bosch cap..End of problem, resistor plug or not....

Roger,

I implied the same suggestion about 7 minutes before you did. You explained it better so I figure both of us will catch hell when it happens. I suppose we take for granted that everyone would look to see where they were drilling, and how deep they could go, before they put the metal to the metal. It's not all that hard to drill through a cooling fin (of course missing the cylinder itself) and bolt the strap in place as well.

What RCIGN1 said..

Can any one post a pic on here on what there talking about with the clamps on the plugs. I know there are not alot of ppl out there that takes pics of all there engines in there planes before they put on the cowl.. It would be nice to see what you are talking about before my new CH gets here... I sent them my money to them a day or to ageo.
Paul

Would posting a couple of pictures of the different caps, with and without ground wires help? I have several ignitions of each CH type but not all are mounted at the moment.

The first picture is a Taurus 3.2 with a CH ignition using the Bosch Cap. FYI, the engine does not come equipped this way, but with the rubber cap and ground wire.

The second picture is with an older Brison 3.2 and the originally equipped ignition. Rubber cap and ground strap. You can see where Brison manufactured the engine with the head drilled and tapped to accept the ground strap. If you have a head that you want to drill to affix the strap, DO NOT DRILL THIS LOCATION! It's directly over the combustion chamber and a depth mistake will be an expensive disaster!

The fourth picture shows an "X" with a pencil pointing to it. This would be one of the acceptable places to drill a hole since there is nothing under it to be a problem. The next picture provides a side view of the open space under the top fin.

The easiest way to do the job would be to drill a small hole the size needed, run a short #4 or #6 screw (depending on the size of the wire lug you use) from the top, and secure under the fin with a flat washer and flat hex nut. Use some blue Locktite on the hex nut, making sure that you do not get Locktite under the lug for the grounding strap, thereby maintaining a good ground contact. Take your time and things will go well.

THANKS
To all,to make it a little clearer i mounted the ground strap to clyinder base bolt,but from what has been said it won't be good enough,i will call CH electronics to get a Bosch cap,don't know how to get a hold of TKG like RCIGN1 said to,and for the time being i want to try moving the ground lead to top cooling fin,did't know it was that sensetive,i want to fly this plane for the first time (snow is gone). i was un easy about clamping the ground to plug (to easy to come off).
THANKS for all of you guy's help,this is my first CH ignition didn't know the first thing about them.this at lease gives me more things to try,i was at the end of my rope,didn't know what else to try!
ENJOY GUY'S!!

closetguy,

Everyone has good idea's as to what you could try and I got to tell you....BTDT. I actually cut the ground wire a little shorter and wrapped it around the plug where you use a wrench to tighten it and put a hose clamp around it. I ended up going to a Bosch cap. The ground is built in. If all else fails, you can unplug every servo, and range check it, with and without engine running, plug one servo back in at a time and range check. This way you can eliminate any problems with the servos. We found this to be the case one time. Once you find out what the problem is post the fix so all can see. Very good info for guys new to gassers.

Don't try to install the Bosche cap yourself. It might require changes in the module to make it work. Send the ignition to C&H and have them do it.
Clamping the pigtail to the spark plug base may look crude, but from an RFI standpoint its the best way to do it. You want to get to the ground the shortest way possible. It won't come off if you clamp it down hard.

Yep. I've clamped CH ground leads to plug thread faces for a long time. Very effective. I found I had to use a properly-narrow hose clamp; if too wide, it would interfere with the head, and not tighten properly. Yes, you *may* ask how I found that out......

well i am still having trouble,i clamp the ground wire to spark plug and it is a little better i get about 40 ft. away from it now before it starts to glich,i ran the antenna wire outside of plane just incase that was it,i will start to look at servos,only four in there now two for elavator,rudder,throttle.and i did switch rx also, still the same.and i am going to double check all nut's and screws for tight fit,i am glad for all the help you guy's are giving me!
ENJOY!

Try plugging the battery directly into the receiver and ignition, bypassing the switches. If you have a switch that is not making good contact, the vibrations will aggravate the problem. I chased a "glitch" with a running engine for 3 weeks once. Replaced the main radio switch and the problem was gone.
Hope it is that simple for you.

I hate it when a new plane does this stuff. I suppose you're at the point where the engine will need to be running while you unplug one servo at a time to locate or eliminate each and every one as apotential issue. Then you have to try a different pair of batteries, one at a time, on the Rx and ignition to see if that's it. Of course you've verified that the spark plus is a resistor type. Ignition battery is new and fully charged? 800mAh or larger? As previously noted, good switches? No loose connections at the ignition plugs? Not using any mylar type tape to hold the antenna on the fuselage? That's been a biggie more than once, to the surprise of a few. Rx crystal taped into the RX to prevent vibrating out?

Good luck but I'm sure you'll find it.