Glitches, help needed
 

Please can anyone help ? I am trying to setup a DL-50 in a PA Edge 540 and I am picking up glitches in my rudder servo (hitec 5955TG). I can only get about 20 paces in a range check with the motor running before the servo starts twitching. I have tried another servo and that twitches. I have even plugged the elevator into the rudder slot (RX) and elevator into the rudder expecting the elevator to glitch but the rudder plugged into the elevator glitched !!!!! I have tried 3 recievers, all give the same results.

I am using a Emcotec DPSI Battery Info Center powered by two 1800 mAh lipo's for radio power and an Emcotec Remote control ignition switch powered by a 1250 mAh lipo. All the radio gear runs down the left side of the fuselage and the Ignition stuff is on the right.

Check out my gallery.

Any sugestions would be great.

RE: Glitches, help needed
 

Do the simple things first. Get some 4 cell packs and plug them directly into the RX and ign. If this works then look at your lipos and the regulators and such like.

RE: Glitches, help needed
 

First:
Does it only happen when the engine is on?
No...Then it's a radio problem.
Yes... It caused by the ignition. Number one cause.................You didn't push the spark plug cap all the way on, it's really had to push on.

RE: Glitches, help needed
 

It only happens when the engine is running. I get a good 50-60 pace range check with the motor off but only about 20 paces with the motor on.

RE: Glitches, help needed
 

Did you check the spark plug cap?

RE: Glitches, help needed
 

As its only the rudder thats twitching, I assume the others are rock steady and responding, try re-positoning your aerial, again I am assuming a wire closed loop linkage on the rudder that may be transmitting RF interferance.

Mike

EDIT: if your rudder cables cross inside the fus they may be rubbing when the engine is running, put a small non conductive tube over one of the cables to isolate it where they cross and far enough on either side of the crossing to ensure they do not touch when going left right.

RE: Glitches, help needed
 

Plug cap is on. I took the CF rudder arm off the servo and put on a stock plastic one and the servo gittered, all while the engine was running. I will check that the wires are not rubbing, but when I took the arm off I thought I was eliminating that problem. I moved the aerial from its original position from down and out the bottom of the fuselage as I thought it was rubbing on the CF tail wheel. It now comes out the fuselage and attached to the top of the rudder. again not touching any other wires.

RE: Glitches, help needed
 

Could it be a bad rudder servo? Try putting it on another channel, and plug something else into the rudder channel.

RE: Glitches, help needed
 

Can you post a picture of your engine / throttle setup without the cowl on?

One of the most common causes for this is metal on metal vibrating. A couple of pics would go a long way.

RE: Glitches, help needed
 

I would look for any metal to metal contact

1. crossed rudder cables touching
2. metal push rod and clevis on throttle or choke
3. rx and ignition battery are located to close together.

Like someone else said try disconnecting the switches first.

RE: Glitches, help needed
 

I would guess you have a bad connector on the servo or the extender

RE: Glitches, help needed
 

Check out the photos in my gallery. I have tried swopping the servos and no matter its always the rudder that glitches not specifically the rudder servo.

Thanks to all who are replying.

Mark

RE: Glitches, help needed
 

Do you have a different RX you can try?

RE: Glitches, help needed
 

This is going to sound really silly but try it. Let your battery pack run down a bit or disconnect it and plug a 6.0v NiCad (run down a little) straight into the Rx and see if it still glitches. IF it stops check the input voltage into your Rx.

RE: Glitches, help needed
 

When I put my PAU Edge 540 together, I deciced to run it with 6.0 V Nimh battery with a regulator. Like you I couldn't get 20 paces away. I did as you did changed everything. Finally I bipassed the regulator, and lo and behold no glitch, out to about 60 paces so in desperation, I took the antenne out of the nice little tube installed in the fuselage, ran it straight out the bottom and taped it underneath, now it range checks out to 300'.

Futaba 9C, 149 PCM
Brison 3.2

Good luck, glitches are a btich!

Dale

RE: Glitches, help needed
 

That may be exactly the problem. Digital glitching due to over-powering the servo. Digital servos tend to twitch quite a bit with a fully charged battery when they are new. Mine do it all the time but there is no problem once the battery runs down a bit or the servos wear in. That's why I told him to run his battery pack down a bit. The regulator is providing full current to the digital servo causing it to glitch. Plug in a slightly run down 6 volt pack and it should go away. IF that is the case then it should be perfectly safe to fly the plane. I run my Rx off of a 6 volt NiMH pack without a regulator. I get a bit of twitching when I first switch on in the morning but I know what it is and it soon goes away. If you have the pull-pull cable system tight it will make it worse. BTW If you don't already, you should have one cable mounted on the bottom side of the servo arm and the other on top so they never touch.

RE: Glitches, help needed
 

I run 7.4 volt Lipos through regulators and haven't had any glitchen problem using the 5955tg

RE: Glitches, help needed
 

Since this only happens when the engine is running, I suspect it is RI relateed. How close is the ignition sub-system to the receiver sub-system? A rule of thumb is at least 6-8 inches.

RE: Glitches, help needed
 

I looked at your pics (nice clean install) Can't really see much that would cause RF from a quick look.

One thing I might worry about is that screw used to tighten the throttle linkage on the arm.. I hope you used lots of loctite?

RE: Glitches, help needed
 

Your regulator may be set differently then his. All he has to do is try it to find out if that's his problem. If it doesn't help then he can move on the thre next step. Sometimes the simple solutions are overlooked.

RE: Glitches, help needed
 

Two things to try. Set the reciever very close to the ignition box and see if glitching increases. If it does then suspect the ignition is sending wild signals........... Find an older non digital am/fm radio and play it near the plane with the engine running. It should pick up the static from a bad ignition.

RE: Glitches, help needed
 

If the receiver is FM type (non PCM), then the distance between the two sub-systems should be far away. So another idea could be to try a PCM receiver. I strictly use PCM receivers on gas-powed planes (with an ignition, of course).

RE: Glitches, help needed
 

I use the Futaba PCMs on all of mine. They will not stop digital twitching though. I would also suggest you seperate the Rx from the EI by at least 12-20".

RE: Glitches, help needed
 

Al,
I was under the impression that the 5955tg can be used with an unregulated 7.4 volts.

I think his problem might be the Emcotec Remote control ignition switch.

RE: Glitches, help needed
 

They can. I don't use a regulator. I still get slight twitching but I fly the plane and it's not a problem. Once you start loading all the other servos it stops.