lifesintheair

My Feedback: (15)

I have a sukhoi with a Fuji 50 I only have fm RX's (Hitec 8CH FM and a 147 futaba FM) and the hobby budget is pretty low right now to buy a PCM RX. I need to know any ideas of what people have used in the past to knock out noise from the ignition. I can get a great radio check with out the motor running but as soon as I start it up, the servo's bounce all over the place ( With 2 different RX'S). I am using a remote cut off micro switch with a 148 servo, 645's on ail, jr on rudder and 5101's on elev. There is no metal to metal at all. Even the throttle has a plastic ball link on it. I even tried 4 new plugs! I am lost.

Please help,
Brian M.

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Icebird

How close is the 148 to the micro switch that it operates. This could be your problem. I hope you have an external switch, so use that, and disconnect the 148 for a test. If it's right by the micro switch, it can transfer noise right into your receiver.

HTH
Jim

lifesintheair

My Feedback: (15)

It's only about 6-10 inches away from it.
I also have a external switch too. I have also heard of people taking the Negitive side of the battery lead and grounding it to the motor? Has any one else heard of this to stop noise?

I will try taking the 148 out tomorrow morning.

Thanks for your help

Brian M.

Geistware

My Feedback: (16)

Just check your ignition grounds.
Make sure it is grounded as close to the plug as possible.
DOn't ground thour the engine mounts or other parts.
Right on the JUG or on the spark plug itself
DO this and your problems should go away

lifesintheair

My Feedback: (15)

This is the older fuji 50 with the Automatic timing module. There is no ground.

Brian M.

hilleyja

My Feedback: (3)

I have the Fuji BT-50SA installed in a GP Christen Eagle II and have no ignition noise problem at all. I am, however, running a Futaba PCM RX, their R129. My range check with engine on and engine off is almost to the point where I can't even see the airplane's control surfaces, well beyond the 100' on the ground. This is my only PCM setup and its beginning to make a believer out of me. I tried interfering with it with my Hitec Eclipse 7 on the same channel, both TXs next to each other, and the Hitec didn't do a thing to my airplane's controls.

I am not using a remote switch. My manual ignition cut-off switch is mounted just under the engine mount box and I do have a choke servo mounted just behind the engine on the side of the engine mount box. My throttle pushrod is a nyrod with a nylon clevis connected to a nylon bellcrank which has a short metal pushrod connected to the throttle lever on the carburetor.

F1race79

My Feedback: (6)

Make sure your reciever isn't hard mounted.
Enough foam it floats not strapped down tight.

tkg

My Feedback: (1)

Go to the CH web site and follow the instalation instructions. at least that will apply to a magneto engine.
www.ch-ignition.com

Tired Old Man

My Feedback: (1)

DO NOT purchase a PCM receiver in with the hope that PCM will cure the problem. It will not!!! You can easily "lock out" all of your controls as the PCM Rx does what it is supposed to do when it encounters interference or loss of signal.

Find the real noise source and resolve it before you do anything else. Your receiver is the least likely part of the problem.

TLH101

My Feedback: (90)

Disconnect one servo at a time while the engine is running to see if the glitch goes away. Nest connect the battery directly to the receiver to see if the switch is worn and arcing. Disconnect your kill switches as well and see what happen. Do one item at a time until the problem is found. You may also need to reroute the antenna as well.
And pay heed to what Silver Surfer said. Don't use PCM until you have the problem sorted out.

3dd

My Feedback: (6)

just finished fighting the same thing with same engine.i had to take the coil off and clean the bottom of the magnet.it had bumped the mag and filled with aluminun and that caused a bad rf in my radio.i also put computer data cables in instead of long flat leads to my aileron and elevator servos.that fixed me rightup

Geistware

My Feedback: (16)

There is a ground.
It may be from the coil to the case but the ground exists.
Make sure there is a good connection and that there isn't any loose metal present.
Something as simple as plating or something insulating metal to metal contact can cause it.

rc bugman

My Feedback: (30)

I just had a research plane with similar symptoms. After an elimination exercise of components, I found the problem was a failing switch on the radio receiver. The vibration from running the engine caused the switch to make and break contact at a high rate of speed. The switch was even isolated from vibration.

I also confer about not using a PCM rx until the problem is found. In fact, I never use PCM receivers anymore on my fleet of 20+ research planes, all gas powered. PCM only covers up the problem, not resolve it.

Hope this helps

Elson

lifesintheair

My Feedback: (15)

I moved the cut-off micro switch and servo all ignition wires against the firewall, I Moved the ignition switch all the way forward also. I am going to move the RX/Battery as far back as I can get them, in the radio area compartment, I am also going to try if all else fails, to make extention leads out of 3 strand sheilded wire instead of the normal leads. I removed the ignition module, cleaned it, checked the motor for loose ground connections and bolts, (No luck looks good). I will try and replace all the switches in the next step if this doesn't work. I am going to try it again tomorrow!

Thanks and keep the ideas comming, (I am sure I will need them. I am not letting this get the best of me!)


Brian M.

3dd

My Feedback: (6)

on your long leads go to the electronics store get 20 guage shielded computer data wire.hook up the colors as follows,red is red black is ground,white is signal,hook the grounded shield wire to the black wire on the reciever end only and cut it off at the servo end,this will take all rf noise out to the end and disapaite it.they are a little stiff but work great .do this on the ailirons and to your elevator servos and i bet your rf will stop.if you need more help on them pm me and i will send you a drawing of it

Meschmidt

My Feedback: (15)

A club member had 10 servos in his plane and one of the servos was vibration sensitive and caused all the servos to jump when the engine was started. Hook up servos one at a time while it is running to see if you have a bad one. Or tap each servo and reciever with the engine off to see if they jitter. Your problem is least likely ignition noise but vibration noise. Good luck as I know this can be frustrating! Paul

Javier Garcia

First of all: everything related with the engine must be far away de Rc equipment as far as possible. This means everything. It doesn´t matter there are not metal to metal contacts as with plastic ball links. if the throtle pushrod is metal or conductive (as carbon is) the plug Rf interference will go to the oposite end. This happens because of the RF from the plug travels through air, and from air to any metal.
If one servo, swicht, battery, cable, etc is near the engine, RF interference could appears.

The generally mÃ*nimum recomended distance is about 10 inch.

PCM is not the solution, only mask one problem until the inteference is so strong, youy wil not control the plane until it crash in fail safe.

My two cents.

lifesintheair

My Feedback: (15)

The only thing I have left to do is change the push rod to nyrod. I have moved everything forward that has to do with the engine, manual cut off switch, micro kill switch with remote servo that controls it, against the back of the firewall. I have tried to disconnect one servo at a time on 2 different RX's and it still does it. It has been raining all day so I have no chance to test it yesterday. I hope to do it today. I will keep everyone posted. THANK EVERYONE FOR YOUR HELP SO FAR!!! I am VERY GREATFULL!



Brian M.

dirtybird

My Feedback: (5)

I think you will find a throttle connection made of nyrod will not help.
Do you have a resistor spark plug? It should have an R in its type number.
The way RF interference gets into the receiver is thru the antenna. If the engine is producing RFI putting the radio in the tail won't help. You have to get it at the source.

dirtybird

My Feedback: (5)

I can't get this page to come up. Whats wrong?

gilcon

It's missing the "s" www.ch-ignitions.com

lifesintheair

My Feedback: (15)

Still raining!!!!!!!!!!!!!! [:@][][&o]

TLH101

My Feedback: (90)

Well, look at the bright side. If it's too rainy to run the motor, you won't have any glitching.
Make sure bypass the switches, especially the main radio switch. I spent 2 days at a fly-in once chasing a glitch when the motor was running. Finally at toward the end of the last day, I plugged the battery directly to the receiver and the glitches were gone. Just an old worn-out switch that was vibrating.
I think, like Paul stated, it's most likely a vibration issue.
Good Luck.

tkg

My Feedback: (1)

When all else fails install a Bosch Spark plug cap from CH Electronics.

lifesintheair

My Feedback: (15)

I just tried it yesterday and no luck at all.

I have moved everything electronic related to the middle of the plane, at least 18" away ffrom the motor and still can't get no more than 10 feet from the plane on a radio check with the motor running.

I went over the motor loooking for any metal to metal or loose bolts, NONE.

I have installed a nyrod for the throttle rod, tried wrapping the plug wire in foil, moving everything forward that concerned the kill switch.

I am lost for suggestions, I even tried 3 different FM RX's. Anyone have any more suggestsions? We are haveing our annual picnic this weekend and I would like to fly it there.


Brian M.