electrical interference
 

I have a new 1/4 scale flybaby with a 28cc gasser and stock ignition on it, i have already changed the complete radio,receiver, servos,switch and battery pack, the elevator and rudder servos are in the rear of the fuse. so i pulled the receiver antenna outside and let it drag the ground because of the wires running down the fusealage. the servo switch is 8"s back from the engine, the battery pack is 13"s away and the receiver is 21" back from the engine. I still have interference, I do have a resistor spark plug in it also. I would really like to fly this as i just finnished building it. Can anyone give me some ideas or help Please........ Thank you !!![sm=spinnyeyes.gif]

My throttle cable is all nylon inside a another nylon tube or case. It is a new NGK resistor spark plug and the plug wire and mag look very good.. Thanks

Thanks to all of your ideas i have the problem cured, Thanks to everyone who helped with your ideas and comments......
Waterloged
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RE: electrical interference
 

We recently had the same problem on a Homelite 25cc magneto equipped engine. We shielded the plug and mag wires and it went away completely. If you have some old television coax cable, you can carefully strip the copper braided shielding off the cable and use that. Ground only one end of the shielding, not both. In other words, run some of the braid, or a wire from the braid to ground on the engine at the spark plug, but don't ground the other end near the coil. Do the same on the kill wires. This changed us from having uncontrollable glitching at a 20 foot range check, to having none at all at 150+ feet.

Good luck,
AV8TOR

RE: electrical interference
 

Thank you very much, I'll try that tomorrow if i can get to it. I have a partical roll of coax from satalite tv, I'm not sure its copper but it should work anyway. I do appricate your input.
Waterloged

:)

RE: electrical interference
 

You're welcome. The shielding doesn't have to be copper; whatever shielding is on the coax with be fine as long as it's braided. Some of the cheaper coax has a kind of tin foil shielding.

Good luck,
AV8TOR

RE: electrical interference
 

Make sure the spark plug lead has a good connection to the spark plug lead. You might even want to polish the connector with some fine sandpaper. Every time I have had a glitching problem it turned out to be a poor conection in this area.
A good source for shielded braid is your local Home Depot plumbing dept. Get a flexible hose of the right size, cut off the ends and extract the hose out of the braid. Just make sure its copper not stainless or you will have a hard time soldering to it.

RE: electrical interference
 

I got some silicone dielectric compound from the NAPA store to use under the cap at the spark plug after I cleaned it as mentioned above.

RE: electrical interference
 

Thanks for your ideas, i have it working now. I had to shield the plug wire, shield the kill switch wire, put a bosch plug cap on it. It seems to work real good now. thanks for all your help.
waterloged.