Reminds me why I don't use or own lipos.
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My servos are very noisy and jittery
- Thread starter cedar
- Start date
Just stirring up trouble.??
Reminds me of an incident a few years ago when was flying an electric plane with the access hatch at the bottom of the plane. The battery fell off during flight and I instinctively started to wildly move the joy sticks to regain control. A couple of seconds later I realized that I had absolutely no control. So I just stopped and hopelessly watched the plane auger down to it's doom. It was both sad and funny.
Scott Page
Very Strong User
Fortunately my Avanti (being relieved of the considerable weight of the Lipo) slowly flat spun to the earth - landing with no damage. Canopy was also undamaged about 20 yards away. I removed the plywood mount from the battery and the pieces still in the plane - glued them back together and fiberglass on both sides. By the end of the day (including a nap) we were ready to fly again.
Well I am back to report my findings, and it looks like the thread took a left turn.
To close out the noisy servo issue: It looks like I discovered that the receiver itself seems to emit some electrical noise. I found that it cannot be within about 5-6 inches from servos or possibly even the servo leads depending on the quality of the servos. I found this more easily when I moved the receiver to my old faithful Seniorita (built in 1995). It has old Dymond s200 servos. The airframe has enough room to keep things separated. Last night was my first flight with the Taranis X9D. I have a long way to go to feel comfortable but the flights were very smooth and I tested the signal strength out to my limit of vision with no trouble. I really like this new radio, I can't wait to put the new r8 pro in my gas plane. It has digital servos so wish me luck.
Now you guys can get back to the bent lipo stories. I have a few of them myself.
Thanks all,
Orville
To close out the noisy servo issue: It looks like I discovered that the receiver itself seems to emit some electrical noise. I found that it cannot be within about 5-6 inches from servos or possibly even the servo leads depending on the quality of the servos. I found this more easily when I moved the receiver to my old faithful Seniorita (built in 1995). It has old Dymond s200 servos. The airframe has enough room to keep things separated. Last night was my first flight with the Taranis X9D. I have a long way to go to feel comfortable but the flights were very smooth and I tested the signal strength out to my limit of vision with no trouble. I really like this new radio, I can't wait to put the new r8 pro in my gas plane. It has digital servos so wish me luck.
Now you guys can get back to the bent lipo stories. I have a few of them myself.
Thanks all,
Orville
Konrad
Very Strong User
R6 is a telemetry equiped rx. That means is is sending out a signal back the to the TX. This is often the noise we see on long servo leads.
Vintage servos may have more issues also, they never planned for us to be transmitting from the plane, or even using these frequencies. But in general I have had almost no issues with this at all.
I just picked up some vintage F3F planes, they have some of the suspect JR servos in them, so they may have an issue. They are very nice servos otherwise.
I just picked up some vintage F3F planes, they have some of the suspect JR servos in them, so they may have an issue. They are very nice servos otherwise.
If you thread the servo lead a couple of times thru a ferret bead most issues can be eliminated. The Ferret bead acts as an RF filter. Some ESC's have this as standard.
Konrad
Very Strong User
Ferrite beads can be somewhat effective for noise suppression on the line. But that are a heavy solution. Often a set of 20 micro-henry chokes will be more effective and lighter than the ferrite beads.
I find that the braided leads are actually more effective than the Ferrite beads and almost as effective as the chokes.
I find that the braided leads are actually more effective than the Ferrite beads and almost as effective as the chokes.
Watch out for those old JR digital servos. I bought a plane with them last year and didn't do my homework about their voltage limits (4.8 volts). I put a 6.6 volts LiFe battery and ended up losing control of the plane and crashing it. Thankfully the damage was repairable. I removed and put away those servos.
Edit: the servos were not bad, just old versions that don't work with higher voltages.
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I just wanted to add my findings to this thread. After all the ideas I received in this thread I figured I needed to reread the manual. I did not understand that I had not turned the telemetry off. I used 2 different airplanes and 2 different receivers R6 and R8 Pro to test things. What I found is this:
Turning off the telemetry stops the jitters on these old servos Dymond S200 and Tower Pro 9gm.
Better quality servos filter the telemetry noise Hitec HS5645MG, HS225BB.
Turning the telemetry down to 25mw also helps a bunch but at what cost?
One thing that threw me off was that with telemetry on I took the R6 receiver out of the plane and installed the R8 Pro. That change caused the servos to be quiet. As it was the flying season here in the Midwest, I just left the R8 Pro in my Seniorita for the summer. I plan to install it in my larger gas plane but for this summer I just left the DSM2 receiver in it.
The Taranis quality feel was an unexpected bonus during the flying season this summer. It fits my hands and flying style very well. OpenTX is a great operating system if you take the time to learn it. Aloft is going to be my new local hobby shop except for the 1500 miles thing.
Maybe someone can point me in the direction to get information on what follows:
My main question about telemetry is that the R6 caused jitters and the R8 Pro did not. What is different about the two?
Where can I find out how the FRSKY receivers treat antenna reception?
Do the two antennas switch back and forth depending on best signal or lost signal?
I added a M+ receiver to the R8 Pro. Does it only take over in the event of the primary failure?
Thanks to all for the help,
Orville
Turning off the telemetry stops the jitters on these old servos Dymond S200 and Tower Pro 9gm.
Better quality servos filter the telemetry noise Hitec HS5645MG, HS225BB.
Turning the telemetry down to 25mw also helps a bunch but at what cost?
One thing that threw me off was that with telemetry on I took the R6 receiver out of the plane and installed the R8 Pro. That change caused the servos to be quiet. As it was the flying season here in the Midwest, I just left the R8 Pro in my Seniorita for the summer. I plan to install it in my larger gas plane but for this summer I just left the DSM2 receiver in it.
The Taranis quality feel was an unexpected bonus during the flying season this summer. It fits my hands and flying style very well. OpenTX is a great operating system if you take the time to learn it. Aloft is going to be my new local hobby shop except for the 1500 miles thing.
Maybe someone can point me in the direction to get information on what follows:
My main question about telemetry is that the R6 caused jitters and the R8 Pro did not. What is different about the two?
Where can I find out how the FRSKY receivers treat antenna reception?
Do the two antennas switch back and forth depending on best signal or lost signal?
I added a M+ receiver to the R8 Pro. Does it only take over in the event of the primary failure?
Thanks to all for the help,
Orville
Thanks for the feedback!
Not sure why that would be the case.
Sorry, I'm not sure what you are asking.
Yes, that is exactly what they do.
Yes, as long as you have it set up correctly, the R8-Pro will get the control from the M+ if the R8-Pro is not able to get a clean signal from the transmitter. It will then switch back as soon as it regains a clean connection. This is done seamlessly.
Wayne,
Thanks for the quick reply. You answered all the questions except one. When I look at the R8-Pro it has a wire with a larger section before the actual antenna. Is this a better quality antenna than the R6,R4,M+ ?
I also forgot that I am still looking for "best practice" ideas on antenna placement. I have always installed the Spektrum antennas in a horizontal parallel to wing span and the satellite in a horizontal front to back arrangement. In one of the forums on this site I saw someone that uses a vertical 90 degree parallel to the wing span with a satellite v running front to back. My idea is that if you turn the airplane in any attitude can at least one antenna be seen by the transmitter. Let me know if this is not correct.
As far as the original issue I have decided that it is time to make sure I use better servos in anything that is important enough to use telemetry and redundant receivers.
Thanks,
Orville
Thanks for the quick reply. You answered all the questions except one. When I look at the R8-Pro it has a wire with a larger section before the actual antenna. Is this a better quality antenna than the R6,R4,M+ ?
I also forgot that I am still looking for "best practice" ideas on antenna placement. I have always installed the Spektrum antennas in a horizontal parallel to wing span and the satellite in a horizontal front to back arrangement. In one of the forums on this site I saw someone that uses a vertical 90 degree parallel to the wing span with a satellite v running front to back. My idea is that if you turn the airplane in any attitude can at least one antenna be seen by the transmitter. Let me know if this is not correct.
As far as the original issue I have decided that it is time to make sure I use better servos in anything that is important enough to use telemetry and redundant receivers.
Thanks,
Orville
On some of the smaller receiver FrSky will use a slightly shorter antenna, these do give up a slight amount of performance, but it is very slight. I would not worry about it.
Antenna placement - Yes, basic rule is 90 degrees to one another. If you have extra receivers, then you can put them into different orientations and or different planes to get maximum options for best angles. If you are not going for long range flights this is not super critical as FrSky tends to enjoy very good range.
I'm generally rather horrible on how I place my antennas in my small electrics, I just slap them in the plane and try to keep them away from other stuff when possible and at a different angle on the 2 antennas. Should I have an RSSI alarm during a flight, I will land and then try for a more ideal antenna placement. This almost never happens. Some of my slope gliders are very small and the antenna are stuffed in where I could get them.. Way less than ideal, and still no issues. The telemetry feed is great as you will get a warning if the RSSI is getting low. I fully respect that and land and adjust if I get a warning. It is a real plane saver.
Yes - Better servos is a good idea.
Anything that does not have shielding these days is very old.
Antenna placement - Yes, basic rule is 90 degrees to one another. If you have extra receivers, then you can put them into different orientations and or different planes to get maximum options for best angles. If you are not going for long range flights this is not super critical as FrSky tends to enjoy very good range.
I'm generally rather horrible on how I place my antennas in my small electrics, I just slap them in the plane and try to keep them away from other stuff when possible and at a different angle on the 2 antennas. Should I have an RSSI alarm during a flight, I will land and then try for a more ideal antenna placement. This almost never happens. Some of my slope gliders are very small and the antenna are stuffed in where I could get them.. Way less than ideal, and still no issues. The telemetry feed is great as you will get a warning if the RSSI is getting low. I fully respect that and land and adjust if I get a warning. It is a real plane saver.
Yes - Better servos is a good idea.
Anything that does not have shielding these days is very old.Joe Garfield
User
Cedar, are you still having this issue?
One thought that came to mind was that some older servos don't play well with newer, high speed/resolution transmitters. I don't know a ton of details about it, but I do remember when I got my previous ultra-low latency radio, the manual said I had to use only digital servos, otherwise they would 'hunt' around for neutral position.
One thought that came to mind was that some older servos don't play well with newer, high speed/resolution transmitters. I don't know a ton of details about it, but I do remember when I got my previous ultra-low latency radio, the manual said I had to use only digital servos, otherwise they would 'hunt' around for neutral position.
Hi Joe,
Thanks for your interest. Yes the issue is repeatable. It is a case of servos designed before telemetry was added to our receivers that cannot handle the receiver being a transmitter in very close proximity to the servo. It absolutely stops when telemetry is turned off. It took me a while to confirm it so there were a few other ideas tossed out from others trying to help.
What you are talking about is how the old servos react to the faster rate of commands from the receiver. I set the receiver to the longest latency setting only because I think I read somewhere that it would overheat the servo and cause it to fail sooner.
Thanks,
Orville
Thanks for your interest. Yes the issue is repeatable. It is a case of servos designed before telemetry was added to our receivers that cannot handle the receiver being a transmitter in very close proximity to the servo. It absolutely stops when telemetry is turned off. It took me a while to confirm it so there were a few other ideas tossed out from others trying to help.
What you are talking about is how the old servos react to the faster rate of commands from the receiver. I set the receiver to the longest latency setting only because I think I read somewhere that it would overheat the servo and cause it to fail sooner.
Thanks,
Orville
Yes, 9ms refresh rates will kill many (most?) analog servos. By default FrSky does not use the faster refresh rates, and I really do not recommend people use it even with digital servos as you will probably forget and some future date may plug in an analog servo and kill your plane. Not worth the risk IMHO.
