I just got back from the club field. My new XYZ 26cc engine ran great. However, there is a tremendous amount of interference to the radio system. When I got out about 30 yards with 1 section of the radio antenna up, all channels went nuts while the engine was running. If the engine is turned off, the interference goes away. What's going on?



[link=http://www.flickr.com/photos/25908573@N05/4201741478/]hi def[/link]

the ignition is creating RF noise.....

It appears that you have located various ignition components (Ign. swtich, cutoff switch and various related cables) together with your receiver components. While the ignition box and battery are located to the front of the plane, everything switch related is intermingled with radio components. I'd move everything ignition related to the front of the plane. Also, you might try bundling your cables together a bit more as they will be less prone to pick up ignition noise that way. Keep ignition cables completely away from receiver / servo cables.

Of course there are the standard things to also check .... is your plug cap pushed fully onto the plug? This is the number one cause of interference. Is there metal to metal contact anywhere in the control system ... especially on the throttle linkage. You might check the dozens of other threads written over the last few years about this subject.

Lastly, some of those low cost (no name blue box) ignitions were prone to cause ignition noise no matter what you do. If you still have problems after you resolve known problems, you may want to suspect that and change out the ignition to the known reliable RCxcel or the same ignition sold by CH.

Listen to Truckracer. You should have your entire ignition seperated from your radio system by 12 inches if you can. You brought all the potential interference from the ignition system right amongst your receiver with the location of the ignition switch. You were smart not to fly and even smarter to post such a clear image of the installation. Lay it out again and do another post. Dan.

Truckracer pretty much covered it.

1st and foremost. Make absolutley certain that the plug cap is on properly. Some are incredibly tight to get on. make sure it has "snapped on" to the plug hex fully. This is a very common cause of ignition interference.

What is the connection between the throttle servo and the Throttle arm? Make sure you have a ball joint on the throttle arm - NEVER use a simple "Z" bend.

I can't see it clear enough but is the throttle linkage a solid wire inside a plastic covering or is it a genuine nyrod (no wire in the middle). If it is a wire running all the way from the throttle to the servo, you have a pretty good aerial there to bring interference back to the receiver.

If you can, move your ignition switch forward (and all the associated ignition related wiring) do so.

One other thing to check. Is your muffler tight? ( know this sounds weird but I actually saw an instance where a loose muffler contributed to an interference issue). My preference is to throw away the exhaust gasket and use Permatex Ultra Copper to seal the muffler onto the engine.

Lastly - as has already been mentioned - some ignition boxes just emit a lot of interference. If it ends up being that, Speak with RC Ignitions or CH Ignitions about retrofitting an RCExcel ignition.

The throttle pushrod is Sullivan's nyrod. It's the kind with plastic tube on the outside and metal wire on the inside. I guess I'll replace it with the all plastic type. A plastic ball link is used to connect the pushrod to the throttle arm. There's no metal-to-metal contact anywhere. I made sure of that.

I'll make changes according to y'all's recommendation. And I'll report back next weekend.

Thanks.

Moving the switch for the ignition near the front and keeping the ignition wires away from the throttle servo and other radio wires should do it. 12" is ideal but not generally possible. Making sure you don't run ignition and radio/servo wires along together side by side is the first objective.

Other things:-
Route your aerial away from any metal pushrods or long servo leads in the tail.
Make sure your battery is man enough for the servos you have. AAs won't fly 5 or more servos in an aerobatic plane.
Add a ground wire from the ignition case to the engine (one of the mounting bolts inside the bulkhead is good). You may have to solder one end to the HT lead braiding if the ignition has a plastic case.

I've done alot, but the radio is still getting interference. It seems to be getting worse.

Suggested mods done:
* separate ignition wires from servo wires
* replace metal throttle cable with nylon cable
* move ignition battery toggle switch to the front near the firewall
* move RX battery towards the back
* move RX battery switch towards the back
[edit]* checked spark plug cap is pushed in all the way, past hex nut

Suggested mods not yet done:
* solder ground wire between HT braiding and engine mount bolt
* move RX antenna further away from servo wires

Questions:
* Does it matter that I'm using PPM on 72Mhz?
* A friend has a CDI module for a BME-50 engine; and he offered to loan it to me for testing. Is it compatible with my XYZ 26cc engine?

Don't know what XYZ uses for an ignition module. Is a pic possible with the brand name? Do not solder a ground cable to the braid. If you have the cap installed correctly all the grounding is complete. You haven't mentioned checking that the cap is fully seated on the plug.

BME used a couple of different types of ignitions. If it's the CH it might work with yours. If it's the Falkon it probably will not. Wiring polarity at the hall sensor is completely different. PPM is a good thing. With PCM or 2.4 your issues might have been temporarily covered up and you would not have found them before the crash. Nothing wrong with flying ppm on 72.

How good a shape is that ignition battery in? What's the condition of the plugs and wiring. How's the state of charge?

Move receiver antena away from everything with rec. Place a worn gear quality hose clamp around sparkplug metal shield & make it tight. Check it out with range test also. Good luck, Capt,n

Yes, spark plug cap is pushed in all the way, past hex nut.

The ignition battery is brand a new, 6V, 800 mah, Nicd battery. I built it with batteries I bought from towerhobbies recently. I think the battery is in good shape because I can very easily flip start the engine with my hand.

The engine is brand new. So the ignition wiring and spark plug should be in tip top condition.

Hey All
You missed an very small but important component. Your ignition TOGGLE SWITCH. Change it out. Get a slider switch.

A couple of years ago, I had the EXACT SAME problem. It drove me nuts. I replaced the toggle switch on a hunch (I had NOTHING else left to change!!!). Lo and behold, the problem went away.
Toggles are not the best switches to use in my opinion in any RC application.

Cheers
Henry

Henry,
I was able to rule out both the toggle switch and Jomar e-switch today. I temporarily removed both switches and plugged the 6V battery straight into the CDI. The results were slightly less interference. I was able to get an extra 5 yards away with the antenna down before the servos went crazy. So, with and without the switches, I got about 10 and 15 yards away, respectively, before getting glitches. With the engine off, I talked out about 40 yards and did not get any glitch.

My toggle switch is super heavy-duty; it's almost the size of a standard servo.

Regarding the spark plug cap, it is completely covering the hex nut on the spark plug. However, I notice there's a little gap (1/8")between the end of the cap and the engine. Is this gap an issue?

kksiu, if you haven't figured it out yet, I have one more suggestion. If you have the antenna of the reciever running through a tube inside the fuselage, pull it out, run it outside on the bottom, tape it to the fuselage. I have had 2 airplanes with the nifty antenna tube, and neither one would work if it was run inside the tube. Range checks with the antenna in the tube, engine running5 ft. moved antenna outside on the bottom of the plane-300ft. TX antenna FULLY collapsed.

on my xyz engine w/ blue xyz ei module, my rudder was dancing to the rhythm of the slight low-stick burble...just the rudder channel...fortunately my fix was to separate ignition from radio leads as much as possible...now my rebuilt xyz has an rcexl ei unit w/ 3/4" plug (replacing the 5/8" bpmr6f)...starts in one or two flips, and no interference...i fly w/ fut 2.4...good luck...ken

I don't have 1/10th the experience of the guys who have all ready responded. I have only built and flown three big gassers. Maybe I am all wet here?

Be sure you are using a resistor plug.

Replace all the switches. It could be a dirty switch or a weak spring in the switch.

Get a 2.4gig radio!

I have used RCEXL ignitins on all three of my planes. I bought them from the Wyoming boys so I know they are the real deal. Some of the cheaper ignitins produce a lot of RFI.

I have only used a Futaba 6EX. I would now get HiTech because of the flap knob vs. the Futaba switch. Anyway, I have never witnessed a single servo twitch with the 2.4 system. I do cluster my RX gear to the rear of the fuselage. I also solder all made up connections. All plugs get shrink tubed. Any slighty questionable connector gets a shot of Deoxit contact cleaner. Replace or clean your switches? I use those great big switches with recharging the plug built in.

Today I flew my Big Bee so high I could barely make out which way it was going, no problems.

If you get shot down it will cost. Your engine will probably be trashed as well as the plane. Why risk it?

I also run dual high MAH RX batteries at 6V. Running a single one at 4.8 is asking for trouble. Big servos draw lots of amps. The 6V system give some "headspace" for the voltage draw. That does not relate to interference though.

I was asking about the ignition type in an earlier post. It's possible it's the ignition itself if of a brand other than the known good manufacturers.

It was noted the batteries were recently bought from Tower. That's one place I don't go for a battery. Unknown quality and the Hydramax units definately aren't on my high list. Might want to consider geting some of known quaity elsewhere.

There are a lot of unsupported wires and connectors inside the fuse. Those vibrate along with everything else when the engine is running. A loose connector or a wire starting to break away at a switch will be a real killer with induced RFI. Check all the extensions and connectors. Replace any extension that has been used in another plane or electrical component that previously experienced a crash. Replace budget priced extension wiring with high quality extensions.

I agree with Piston. Get rid of toggle switches and replace with sliders.

If you have a shielded plug wire a resistor plug should not be used. There's a resistor in the cap of sheilded wire plugs. Check that the plug is installed tightly. Replace the plug in the event the insulator has a hairline crack in it. Replace the plug with another to eliminate another possible source.

Pull the plug cap and see if there are any carbon tracks running down the outside of the spark plug. If so, replace the ignition,and the spark plug. Look inside the cap when turning the engine over with the ignition on. Is the spark eminating from the end of the spring and terminating directly over where the spark plug should be, or is it arcing to the side of the cap? If arcing to the side, replace the ignition.

Just looked at another thread covering an XYZ engine. Pics showed the ignition. Call someone that handles RC Exl ignitions and buy one. Get rid of what came with the engine. Don't discount any of what has already been posted. There's some great trouble shooting and advice in this thread.

CH Ignitions.
Wild Hare R/C
Southeast Engines
Valley View R/C
RC Extremepower
RC Ignitions
RC Aero Products, LLC, and about a dozen more if you look hard.

...and not using AA batteries for the receiver.


Hope you all had a good crimbo and are relaxing now [sm=regular_smile.gif]

If it came with a plastic-cased, no-name ignition, try making a shield out of a magnetic type tin can. I once made a box out of a tin can(not an aluminum beer can) and formed it to the ignition. Then I soldered a wire on it and grounded it to the motor case. Problem went away. AND this was on 2.4Ghz. Some of those cheaper ignitions are just noisy. Especially on a smaller fuselage where space for separation can be limited.

I 2nd chucking the noisy stock ignition and getting an rcexl.

Thanks everyone for helping me out.

Hmmm ... seems that I suggested replacing the blue box ignition way back in post 3 of this thread. Also listed many of the standard fixes associated with this sort of problem. Many people have posted problems on this forum regarding the blue box ignitions. Yes, some make them work but I expect they're in the minority of users. I would also bet they follow most of the traditional rules for ignition installations too.

Is a 72MHz radio more susceptible than a 2.4 GHz (JR, etc) radio to gasser ignition EMI/RFI?