fibchem

I have a fpe 3.2 in a 30% edge. I have the receiver far away and even used a pop can to try and stop with interference. The antenna is out the bottom of the plane. It is a fm rec. Could a pcm solve this????????

jjmiller1

Most say that a PCM would only hide the problem, not really solve it (Lotsa controversy). I had interference issues with my FPE 2.4 in my 25% Edge. After lots of experimentation, I solved my problem by moving all ignition components (Module, switch,battery, wires) up to the firewall / engine box area. Then I moved all radio gear (Battery, switch,receiver, servos and ALL wires) to a location behind the wing tube. Now there is no less than 14" between anything connected to the receiver, and anything connected to the ignition. I wish I would have tried that first, woulda' saved some trouble. If you don't already know, you also should have a non-conductive pushrod for your throttle linkage, I used a carbon fiber rod. If all this fails, then you might have to get a Bosch cap for your ignition if you don't already have one (this may or may not be difficult). Just try moving everything first.

Good luck,

JJ

ptebbe

My Feedback: (27)

Lots of info about this on RCU. I tried just about everything to eliminate interference with my FM receiver. Ignition components isolated to firewall area, bosch cap, receiver and all components 12" away. Unplugged one servo at a time until only throttle was left. Still interference. Tried a noise eliminator on that servo....still noise. Went to PCM......works perfectly. I realize that it might be hiding a problem, but there WAS NO solution using FM.

mglavin

My Feedback: (31)

Carbon-fiber rods are conductive which means they radiate noise... Sullivan makes some precision carbon impregnated control pushrod/tubes which work fine and do NOT conduct RFI.

The noise problem could be something as simple a a bad timing unit.

I have yet to run into a situation that was unsolvable. Do your best to eliminate the source. It will ultimately be worth the effort.

PCM will NOT solve the interference it may hide it visually but it will still coexist within your model.

Describe your complete installation, location of equipment, wiring, batteries, switches, ignition system, spark plug and all. Let's find the problem.

jjmiller1

mglavin,


Interesting, I keep hearing that carbon fiber rods are electrically conductive. I'm using a Sullivan carbon fiber rod for my throttle, and the first time I heard this info I grabbed a piece went to my bench and checked resistance with a meter scaled to 50 megohms, no measureable conductivity (even when measuring across a tiny 1/8" area). So, an even better test, took a piece to work, hooked up to a calibrated Hi-Pot tester, set it for 5 kilovolts, couldn't get it to fail hi-pot ac or dc, in fact, my throttle rod makes a better insulator than some insulating materials we test at work. I'm wondering if perhaps some other carbon fiber rod manufacturer is using graphite or some other conductive material within their recipe.

Curious,

JJ

RC Extreme power

My Feedback: (24)

What type ignition do the FPE engines have.
Milton

jjmiller1

The standard ignition is fixed (not sure what type). The upgraded ignition (additional $75 from FPE) is the CH electronic.

JJ

mglavin

My Feedback: (31)

JJ

Which Sullivan rod are you using? They have at least two types. One is designed to not conduct that latter is another story!

Graphite has also been known to be conductive as you suggest. It's certainly possible that graphite is used to provide some lubricity?

I seem to recall FPE's fixed module is a Reitchmuth (spelling). It's likely I am mistaken.

jjmiller1

Maybe since it's only "Carbon Fiber reinforced" it only contains a small amount of carbon...........Perhaps?

JJ

lwheat2083

First of all carbon fiber is not necessarily dc conductive but an excellant RF conductor. The other thing to try is to make sure you have no metal to metal that may be loose or sloppy and rubbing against each other. This will also create RF noise. I am using the CH Electronic ignition with the Bosch cap on a FUJI 50 and Hitec FM receiver and there is NO noise even with the receiver as close as 6" on the test stand.

jjmiller1

Hee-hee-hee, I think I'll use carbon fiber insulators on my next dipole antenna, just to prove my theory.

JJ, aka - KB9MXE

mglavin

My Feedback: (31)

JJ

Those are the Sullivan's rods I was eluding too.

jjmiller1

You know mglavin, this discussion inspired me to read up a little on "Carbon fiber", and now I've seen that there are all kinds of different formulas,compounds,weaves, grains etc. all having widely different properties (I love the internet). Some are excellent conductors, thermal and / or electrical, some aren't, some have rigidity, some are very flexible. I also read that most referred to carbon fiber as "Graphite composite" in the past, and occasionally still do, while it wasn't really accurate. I guess with all of the various types and properties associated with carbon fiber, the term really doesn't tell us anything about the item in which it's contained, except that it's lightweight. It's been interesting. Now if I could just remember what I was supposed to do today, if it's not too late.

JJ

ronk1

My Feedback: (25)

The 2.4 comes with Ridge ignition CH is an option, 3.2s come with CH.