[chuebner]

Hey guys,, a fellow flier up here is having some glitching on his aircraft.He is using a FUGI IMVAC 50cc EI, New Futaba 7C tx, Futaba Digital Servos and Futaba rx. The engine revs up and down.and control surfaces flutter also only when the eng. is running. Could it be the Electronic Ignition causing this or what??? He has everything isolated. What should he try??

Thanks

Curt

[SJrcflyer]

Yes i would say it is his ignition, but something is causing the interferance, and please do NOT just put a PCM Rx on it.

1) Does he get a good range check with the engine off? If he does then your most likely culprit is the ignition.

2) How close is the ignition box to the radio gear? It should be as far apart as possible. That goes for batteries, servos, switches, everything.

3) What kind of extensions is he using? I would recommend HD TWISTED extensions. Long straight wires are not good.

4) Metal to metal connections are a BIG no no. That is for all surfaces not just throttle and choke(if he is running a servo there). I would make sure that there is no metal to metal connections.

5) Play around with the location of the antenna wire, sounds simple but this can help alot.

Good Luck!!

Chris

[Randy Brown]

Curt you should take some pics of the inside..be easier for us to solve the problem if its over radio setup/gas

Randy

Originally Posted by chuebner

Hey guys,, a fellow flier up here is having some glitching on his aircraft.He is using a FUGI IMVAC 50cc EI, New Futaba 7C tx, Futaba Digital Servos and Futaba rx. The engine revs up and down.and control surfaces flutter also only when the eng. is running. Could it be the Electronic Ignition causing this or what??? He has everything isolated. What should he try??

Thanks

Curt

[Ramz]

Here are a few things I would look for:

Make sure the spark plug is the same as the original that came with the engine.

the metal braid on teh wire going to the spark plug should be in good condition (it might leak RF is the braid was damaged)

make sure the spark plug boot is making a good connection with the plug.

how good of a range check (in feet) does he get with the engine off and the engine on?

make sure the igntion has its own battery that is 100% seperate from the Rx battery

is he using a pull pull setup for the rudder?

that's just a few things I can think of. Like Randy said, lots of detailed pics would be helpful in diagnosing the problem.

[chuebner]

Thanks guys... I will try to get you some photos and post them at a later date. I can see how that would help you diagnose the problem quicker.

Thanks
Curt

[sylo26]

I had the same problem with mine. This motor start well and run well with good power but I can't imagine how fuji never put a metal shield on the sparkplug wire as all other good company make. I tried to find metal shield(ground cable) here in my town but never found , if somebody find some , please let me know.
So to resolve my problem I putted an PCM rx(forget to resolve it on FM, sorry for the guys who insist to do that before, I made about 50 flight on pcm and had no problems). Also I putted my antenna outside of the airplane and I also put my ignition battery on the firewall(important). My receiver batt is +/- 20'' from the motor; if it's to close from the motor it will glitch. Also, I tried with twisted extension with no difference, it's not the solution.
So this motor is great , except this stupid interference problem , due to the ignition system(sparkplug wire).
Again , sorry guys , on FM , with this motor , it's impossible. Paul

[SJrcflyer]

I am not doubting you had troubles to find your interferance problems, but I find it hard to think that a company would sell and distribute an engine that wasn't possible to run on FM. The RF noise has to come from somewhere, I'll be it the smallest thing.

It took me well over 4 weeks to find my issues, and for me it came down to too many long straight wires. So twisted extensions solved my problem.

Again don't take this the wrong way, but in each and every plane the RF problems will be different.

Just my opinion.

Chris

[spillproof]

Cap at the club had the same type issue. Throttle would jump around and the elevator would go a bit whacky. Rerouted the antenae outside the plane, through the top without any loop backs, and away from the servo's. Cleared it up.

[Lash]

Where would you get twisted JR extensions for a decent price?

[Ramz]

Originally Posted by 72

Where would you get twisted JR extensions for a decent price?

www.greathobbies.com

do a search for "mpi twisted"