Hi Guys,
I just purchased a ZDZ 40 engine. Real Nice looking! Now if it only runs as good as it looks! (from what I heard, it does!). My issue (or worry), I've been told and read that you should keep ignition parts far away as possible from R/C radio gear for fear or interference issues (minimal supposedly with full shielded Ign. system, like the Falkon system that came with the ZDZ). Nevertheless, I'll keep them separated as far as possible for safety sakes. Now my main question,... should I also worry about the placement/proximity of the ignition battery and cable? Does any one know if shielded systems assure that no EMI junk gets onto the power leads of the ignition battery? I currently plan to have both battery packs (ignition and radio gear) side by side towards the tail of the plane (for adjusting C.G. properly). Additionally, I plan to expend the ignition battery cable a bit (from 12" to 24"). Is there potential issues with this installation ???? Help! This is my first "gasser" and want it to be a GREAT experience!
Thanks in advance!

p.s. Has any one used ferrite beads to supress interference ? (and if so, where do you place them... these good on servo leads too?)

BAD Idea

You went to keep all engine related equipment (batt.,switch, ignition module) separate from your radio gear! As well don't use a steel push rod or cable between your throttle servo and engine.
If you have any other questions fire away. Best of luck!

Doug

You should isolate ign batt as well from the receiver battery. It can difficult to do this i realize for balance purposes but it is just as important to isolate the complete ign system from any receiver parts.If you want to completely isolate the ignition from the receiver you could go with the Optic fiber cable sold by Roger Fortes who is a regular on this site and has advertisements for his sytem . Good luck Bruce

I am currently gathering parts for my first gasser also, and would like for some of you veterans of gas engines to give me some ideas as to where in the plane I should go about placing everything as a general rule...ie: reciever, battery packs. Also, if not using a metal servo rod on the throttle, what type would you reccomend as an alternative? I am going to be using one of the new style US 41 engines, Hitec HS645MG servos on all but the throttle, and a JR S-PCM reciever (havent decided which one yet). The aircraft in question is an 84" span Edge 540. NOt trying to hijack the thread, just thought I might get a little info along the same lines. Thanks!

Wow! Even the batteries ??? Darn.
I'm using an all plastic Sullivan flex pushrod for the throttle (only metal is 1" of threaded rod on each end. Luckily, my plane has elevator servos and rudder servo mounted on rear of fuselage (i.e., short <4" metal pushrods with plastic Dubro ballinks and clevises). I do have long runs of servo cables I'm pulling through a plastic tube to keep them on one side of the fuselage, away from other stuff like batteries and their wires. Currently, all my ignition stuff (switches and all) are isolated to one side of the fuselage while the radio gear is on the other. But Geeee!!!! Batteries too !!!?? Any way to sheild them or something? I REALLY need the weight toward the tail. Maybe I'll push the receiver battery back further (if possible?) and then move the ignition battery closer to the ignition module.
Thanks again for the responses!

Definitely batteries too. It's one of the worst possible offenders because it's hooked directly to the ignition module, which is probably the main source of interferance.
If you just move the battery up a little and the rx battery back a little, you're not helping anything because the ignition battery will still be in close proximity to servo leads, the antenna, rx switch and that type of thing.
The rule of thumb is to keep everything that's directly connected to the ignition at least a foot away from everything that's connected to the reciever. That means everything...batteries, switches...everything.
No sense in using a nyrod for throttle servo, separating your reciever from the ignition module and all of that if you're going to take the ignition battery and place in next to reciever battery.

Now, as a disclaimer...People have broken all of these rules from time to time and gotten away with it but as a general rule of thumb, these are the rules.

BTW, the ferrite rings are a good idea but not a substitute for separation in my opinion. You generally place them as close to the receiver as possible.

Amen, preach on.
Distance is good, distance Squared is better

ON my first gasser, I didn't obey the "separation" rules and had mounted a kill-switch and throttle servo on the firewall, with no isolation. ALWAYS had reduced range, but never figured out why.

For your CG issue, the RX battery CAN go all the way back to the rudder post, if you need to, and move the RX back there, too! The idea is to Absolutely, Positively, keep the ignition battery and any ignition related electrical stuff in front of the firewall, and minimum of 12-16" from ANY Rx related cables, harnesses, antennas, switches, etc.

We may not like it, and I ignored it - ONCE - and won't again.
If I can't get appropriate separation I choose a bigger airplane.