rpmtech

My Feedback: (6)

Hi Guys I have a 34cc briggs four stroke {from weedeater} in a 1/6 scale tank and I am getting alot of glitching when running. I have wrapped the ignition wire and cap with aluminum tape and have installed toroids on all servo wires right next to the receiver, but still alot of noise. I do have a servo mounted close to the engine for throttle but I have tried the receiver well away and still alot of noise.

What noise supression techniques are you using for these weedeater type engines? I am probably going to use PCM {Using std 7 ch Futaba FM now} but I still think this is excessively noisy and want to minimize it before I switch.

Also for my electronics system, the engine is grounded to the receiver ground. like a car I have everything grounded together. I needed to do this for the type of speed controllers and swtiches I am using. Does this make a difference?

SO what is the best way to quiet the spark down?

Thanks

Rick

smallplanes

My Feedback: (3)

Are you using a resistor spark plug?(it should have an R wrote on the plug) You can not have a metal push rod to the throttle it must be some kind of plastic.



smallplanes

buck1856

My Feedback: (49)

do you have an off and on switch to kill the engine and where is it located.if you do,get rid of it and use throttle to kill engine.

rpmtech

My Feedback: (6)

I dont believe it is a resistor plug, there is no R, obviously that would be a place to start. Is there really a big RF difference beteween the two? What about the cap and wire?

The throttle is a plastic ball link, so no metal on metal there.

Yes there is a switch, I really dont use it but it is there. It is strung up forward so maybe there is RF coming from those wires? does that switch just ground the ignition for shutdown? I swear I tested it and to my suprise the switch had to be closed to run the engine, but will double check.

Hmm those switch wires got me thinking, maybe there is a pretty good pulse going through them radiating out...

Thanks alot for the input guys. anything else you can think of would be most welcome.

tkg

My Feedback: (1)

Its not just metal to metal, but a length of wire nest to an engine can act as an antenna and radiate into a servo.

Coloradobanjo

My Feedback: (3)

You mention that you have everything grounded together. I undestand that. However, the technique you use is critical. All the receiver and servo circuitry must be grounded together at ONE point, and all the ignition circuitry must be grounded together at ANOTHER point, and then there must be one good copper wire between these two grounds. That is standard procedure in combined RF, analog and digital circuitry. Finally, engineers who work in this field only do so much calculating. Then they get busy and tinker. They try different things, because RF is a black art.

tkg

My Feedback: (1)

Common radio ground, yes...Common ignition ground, yes...... Common to Common NO, bad ju ju

rpmtech

My Feedback: (6)

So you guys are saying that the engine ground should not be connected to the radio ground?

Also looked at my plug and it is a Champion R something or other, I assume the R is resistor?

Oh yeah the throttle rod is only about 1" of metal

tkg

My Feedback: (1)

Check out the instructions page www.ch-ignitions.com

smallplanes

My Feedback: (3)

Yes that is a resistor plug. So you know thats not any of your problem.




Thanks
smallplanes

b717doc

Same problem with my Mac 32......Found One of 2 wires coming from coil cut off. replaced coil and grounded same wire to engine, no further interferance noted......(no kill switch installed)

Lee MRC

Hey guys, it is the inductancve of the connection that is biting you not the length! Try paralleling several wires togther to accomplish a connection and you will find a reduction in interferance. That is to say parallel several, the more the better, insulated wires in lieu of one greater sized wire to connect the circuit and you will reduce the inductance of the circuit, therefore reducing the amount of inductive reactance in the circuit and the radiated electro magnetive interference.

A wire is an inductor. Inductors in parallel allways reduce the total inductance. Try to make all wires the same size and length as this will provide an inductance that is the amount for one wire devided by the number of wires in parallel.

I know that this technical but I have to reduce it to simple terms and I hope that it will help some one.

Lee K5MRC

Fly the airplane first

Please excuse the spelling but I am from Texas

Lee MRC

Hey guys, it is the inductanc of the connection that is biting you not the length! Try paralleling several wires togther to accomplish a connection and you will find a reduction in interferance. That is to say parallel several, the more the better, insulated wires in lieu of one greater sized wire to connect the circuit and you will reduce the inductance of the circuit, therefore reducing the amount of inductive reactance in the circuit and the radiated electro magnetive interference.

A wire is an inductor. Inductors in parallel allways reduce the total inductance. Try to make all wires the same size and length as this will provide an inductance that is the amount for one wire devided by the number of wires in parallel.

I know that this technical but I have to reduce it to simple terms and I hope that it will help some one.

Lee K5MRC

Fly the airplane first

Please excuse the spelling but I am from Texas

I do know if my first try made it or not.

This is a retry with corrected spelling, I think HI HI