battery noise
 

mounted ignition pack and receiver pack next to each other and worried about interference . shielding with aluminum foil and grounding to motor? also a friend of mine suggested connecting the two negative leads to each pack together ,he said in doing this it would eliminate any noise ? does anyone have any input on this . as i was told by another person ignition wiring and radio accessories should all be kept separate by 8" or more ? any help .

battery noise
 

Interference(EMI) sometimes requires a little magic to remedy but for the most part, you're right about keeping the radio components separated from ignition.

battery noise
 

yes try to keep apart but i can not as plane is only so big and trying to cut weight . sheilding info is what i need . can foil wraped batteies be grounded to motor , and neg. leads to packs joined not ah yes a little magic!

battery noise
 

I don't see the need to shield the batteries. Not much benefit there. You can make sure the servo leads stay clear of the ignition and don't tie the negative lead to the engine. That could be a bad thing. It is possible that you may tie the negative lead to the engine through a capacitor but not likely. You want to AC couple not DC couple. Big difference. Make sure the antenna goes straight away from the engine and it tries to stay away from the servo leads. As far as the magic thing goes, each plane is going to be different as far as EMC (Electro-Magnetic Compatiblity) goes. My experience with EMC is that sometimes simple things have the biggest impact. Orientation of RF components are what you need to look at. You have to go with what works.

battery noise
 

In some cases, having a common ground (tie all negative leads together) will help. The ground must be a good rf ground though, i.e. a rather wide strip of copper braid etc. Just a single wire will not work as well although it might help. An old rule of thumb (quite a few years back when working in lots of radar and rf) the strap had to be 1/4 as wide as it was long. This is not practicle for many applications.