Ailerons twiching on idle
#76
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dirty
How about this, if the cause is vibration, what will happen if I unscrew the servos from the wing but leave them connected to the receiver then run the engine?
I could test the servo theory tonight,mmmmmmmmm also test other servos.
How about this, if the cause is vibration, what will happen if I unscrew the servos from the wing but leave them connected to the receiver then run the engine?
I could test the servo theory tonight,mmmmmmmmm also test other servos.
Last edited by CARS II; 07-27-2014 at 11:53 AM.
#78
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Just came back from the field, changed the Ail servos, It got better but it didn't solve the actual cause, the new Ail servos where twitching not as much like in the beginning but some, very little but still there, it looks like that every time I change or move something it gets better but that doesn't solve the problem ( I'm learning a lot from this )
So this time we are going to the root of the cause ( the ignition box ) like Thai said, it has to be isolated even more than what I have done so far by adding the copper grounding wires to the ignition box, also will be shortening the grounding wires by reattach them on top of the cylinders on one of the fins, that is what I will be doing next, most likely by Friday or Sat.
So this time we are going to the root of the cause ( the ignition box ) like Thai said, it has to be isolated even more than what I have done so far by adding the copper grounding wires to the ignition box, also will be shortening the grounding wires by reattach them on top of the cylinders on one of the fins, that is what I will be doing next, most likely by Friday or Sat.
Last edited by CARS II; 07-27-2014 at 05:45 PM.
#79
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Youi said this is used equipment. Servos as they get older will tend to hunt under vibration. In fact brand new servos will sometimes hunt under vibration. Are your ailerons static balanced? It would help if they are.
Hunting is a characteristic of low deadband strong servos. You may not see it but its there. JR servos have been set up with zero deadband. That means they will always hunt.
If I were you I would go ahead and fly it. You dont really have a problem.
Hunting is a characteristic of low deadband strong servos. You may not see it but its there. JR servos have been set up with zero deadband. That means they will always hunt.
If I were you I would go ahead and fly it. You dont really have a problem.
#80
Also.... Your aileron leads being long make good antennas and you might try twisting them rather than having them run straight. That was on old trick on television twin lead to antennas as if you run that straight, passing cars would cause noise on your picture. Twisting it allows it to isolate the interfering signal electromagnetically.
Don't rule out the vibration factor quite yet as I can see that is plausible.
#85
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Regarding the two systems , the radio gear ( all of it ) is 20 inches away from the ingnition system and the ignition componentes are all on top of the engine box.
The kill switch is an Rcxel V2.0, even before it was added the twitching was there end very strong, that is the only lead between the two systems
The kill switch is an Rcxel V2.0, even before it was added the twitching was there end very strong, that is the only lead between the two systems
#87
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I personally don't like the opto switches, especially the RCXEL unit. I have read multiple issues like yours being caused by the switch. That being said, try the tape on the ignition module and you may want to try different antenna locations. I don't think that the RF is getting into your RX though. It seems to be getting into the aileron signal wires. Using twisted extensions was mentioned and is a good idea. Don't use Hitec Karbonite geared servos on a gasser. The gears are brittle and shear off with vibration. Does this model have rudder pull pull and if so are the cables steel?
#89
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The Aileron servos are carbonite and they have been removed ( today ) they feel like there is sand in them, i will replace them with metal ones, pull pull yes,not sure if metal ( will have to check ) when I get the new metal servos I will cut the lead and add a twisted lead long enough to reach the center of the wing.
#93
The Aileron servos are carbonite and they have been removed ( today ) they feel like there is sand in them, i will replace them with metal ones, pull pull yes,not sure if metal ( will have to check ) when I get the new metal servos I will cut the lead and add a twisted lead long enough to reach the center of the wing.
Even if the servos are not the cause of your problems, I suggest that you replace them with metal geared versions.
I'm in agreement that you should dump the opto kill switch, and I like the idea of grounding the ignition box. Make sure that you spark plug cap fits securely. Metall pull/pull cables can kill you. The throttle push rod, should be non metal. I use nyrod. These things keep me relatively trouble free, and may help you to be the same.
If it were me, I would not make sweeping changes. I'd try one thing at a time, testing after each change. That way, when the problem goes away, you'll know what it was.
Last edited by TomCrump; 07-28-2014 at 01:13 AM.
#95
I think I am going to fashion a kill switch which is just a micro-switch driven by a wedge on the end of a nyrod control rod. Those electronic (opto-isolator) kill switches do not help the isolation challenge. Granted, the majority of the energy is electromagnetic propagation which can travel without a conductor, but anything to reduce the coupling is bound to help. I know my Tartan Twin is very noisy. So throttle and kill switch can both be nylon rods.
#97
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I have used metal pushrods for throttle and choke with the servos mounted at the bottom of the motor box without issue
Carlos, it looks like you have an older BME twin there with a CH ignition that has braided ground straps that attach to the cylinders. Those grounds have to be good. Try hitting the connection with an OHM meter and see what resistance you have. Do you have resistor plugs in the engine? Maybe a newer ignition with shielded wires and caps would be a consideration?
I've seen folks go to PCM, separate channels/receivers, and 2.4Ghz setups trying to mask glitching. If you fix it at the source (shielding the plug & wire), you'll find 99% of the troubles go away.
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That's not a good idea, as any metal can conduct RFI. You may get away with it, but nyrod is better.
Exactly. Good caps & ground straps will fix most RF-caused glitching. (Not picking on you, SR&T, you have probably seen more installs than most.)
I've seen folks go to PCM, separate channels/receivers, and 2.4Ghz setups trying to mask glitching. If you fix it at the source (shielding the plug & wire), you'll find 99% of the troubles go away.
Exactly. Good caps & ground straps will fix most RF-caused glitching. (Not picking on you, SR&T, you have probably seen more installs than most.)
I've seen folks go to PCM, separate channels/receivers, and 2.4Ghz setups trying to mask glitching. If you fix it at the source (shielding the plug & wire), you'll find 99% of the troubles go away.
In the old days of AM PPM if you used a metal rod without isolation to the motor, you would get a spark caused by pickup of static electricity or dissimilar metals rubbing together.That spark caused the problem. All that was needed was a plastic connector to the motorto fix the problem. AM PPM is very susceptible to RF noise. Even then I was able to use a steel cable. I flew AM PPM from 1965 to 1978 with 5 years formula 1 pylon racing.
Now we have 2.4 GHZ spread spectrum communication.Most dont realize it but SS in a tremendous break through in wireless communication. Its made all of the wireless communications we have today possible. SS allows you to reach down in the noise level by as much as 40DB. This allows you to use much less power. Without it we simply would not be able to use 2.4GHZ. There is too much propagation loss.
In SS the transmitter and receiver agree on a code for each transmission. If the receiver dont see that code it wont respond.Any kind of interference does not have that code.If there is enough interference to wipe out the band the receiver gos into failsafe. It dont glitch.
You people need to come into the 21st century. Things have changed
#100
The reason for the kill switch is the ignition engine. There have been cases where the throttle plate vibrates loose and engines run full throttle until out of fuel. Not as likely with glow engines. The old 72 Mhz receivers were likely a lot more susepeptible to noise than the current 2.4 Ghz receivers.