I came upon and bought a used pristeine WH Sukhoi 87 in. wing span.

Having flown the airplane once I found the airplane to be somewhat tail heavy.

As this is my first gasser and trying not to add unnecessary weight, I have considered moving the batteries foreward to on top of the engine box / foreward of the firewall, and about 4 to 5 inches from the ignition box.

Please note that my receiver is mounted 6" aft of the wing tube, a considerable distance away from the ignition.

My questions are:

1) Would EMF generated by the ignition affect the voltage to the receiver and would it be significant?

2) Would the batteries be exposed to too much vibration if they were located at this location?

Thank you

Well first off I would go to the Wild Hare Web page and download the Generic instruction manul and any specific manuals or instructions for your plane and read those. As you did not put this plane together it might provide a good reference point as to what Wild Hare had in mind for the building.

As to the batteries you can pretty much put them where you want to so long as you install them correctly. The batteries should be fine up front if monted with some foam. EMF or other forms of interferience doesn't really affect voltage, it just screws with the signal so that shouldn't be a problem. Your receiver weighs almost nothing in the overall scheme of things and should not be a problem mounted where it is. If the plane really is tail heavy I would move the battries as required to get the initial ballance recommened in the on line manual. After that it is pretty much a matter of ballancing the plane for the way you like to fly.

The other thing you can do with a round cowl plane is to space the engine out farther. There is no set distance for engine to firewall, and moving it out farther will change the balance dramatically. A heavy spinner also has a big effect.

TF

Thanks rctom & sailing1, I appreciate your quick response.

The previous owner left a very detailed build on this web site so I set the airplane up as close to how he had it. The CG fell about 3/4" aft of his marks and it flys tail heavy. Not real tail heavy, but it made for some sporting landings.

I am reluctant to add weight so I'll opt for moving the receiver batteries to where ever it takes. I wanted YOUR opinions / judgement before I moved the receiver batteries in close proximity to the ignition module. Since I am using Spektrum, I am not too concerned about RF inteference. The receiver is mounted over 21" from the ignition.

My gut tells me that any EMF generated by the ignition would have negligible effect on the DC power supply to the receiver, even if I mounted the batteries close to the ignition.