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CRASHED plane due to servo chatter!! :>(

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CRASHED plane due to servo chatter!! :>(

Old 04-18-2011, 06:16 PM
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doug_newman
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Default CRASHED plane due to servo chatter!! :>(

Can anyone help explain to me how I developed servo chatter? Plane was fine the last time I flew it and had no issues. I all I did was charge my battery. When I got to the field and turned the power on the aielerons started to chatter. I gave it some left and right aieleron with the tx and it quit. I thought I was good to go. I took it up, flew for about 3-4 minutes when all of a sudden I lost control. I thought Ilost complete reception when Irealized I still had some control. It quickly came out of it and 30 seconds later it did it again. I now knew that I had to get it back on the deck. When I was trying to set it up for an approach, I lost it and it crashed hard. After I picked up the pieces I re-attached the battery (the tx was turned off) the aielerons immediately started to chatter. What is causing this issue? Ihave JR servos and a spektrum 7 chanel receiver. The aielerons are connected via a Y harness. Any help or suggestions will be greatly appreciated!! Thanks in advance
Old 04-18-2011, 08:27 PM
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Gray Beard
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Default RE: CRASHED plane due to servo chatter!! :>(

This is why I never use Ys in any of my planes. When a friend owned a hobby shop we took new y harnesses out of the package and tested them. Several of them were bad right out of the package. I don't even use extensions, if I need longer leads I just lengthen them with added wire soldered/spliced. At the field when someone is having problems with there servos acting funny the first thing I ask is if they have a Y harness, if they do then removing it usually cures the problem. Your 7ch radio should be able to do away with using them. For folks using the smaller radios sometimes Ys are the only way to set up a plane, they just have to be aware there can be a problem. One of the main reasons for buying a bigger radio is to be able to program a plane without the use of Ys, they are just another point that can create a problem. Just having a dirty terminal on one can create a lot of trouble. Read your radio instructions and do your set up without using Ys, that's what the added channels are about.
Old 04-19-2011, 02:36 AM
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Kaos Rulz
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Default RE: CRASHED plane due to servo chatter!! :>(

Doug

The chatter you mentioned did not crash the plane. In fact servo chatter is commonly noticed after a fresh battery charge. If you had walked a few feet away from the plane, the chattter should have stopped. Your transmitter was swampping the receiver causing the chatter. After the crash, you turned on the receiver without turning on the transmitter and the servos again chattered. This too is normal, as there was no controlling RF carrier from the transmitter. The recceiver picked up stray signals causing the servos to go wild. It is always recommended to turn on the transmitter, then the receiver, and vice versa when you turn the units off. (receiver first, then the transmitter).

I agree with Gray Beard about the Y- harness being the culprit. I have never trusted them and have never used them.
Old 04-19-2011, 09:23 AM
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Default RE: CRASHED plane due to servo chatter!! :>(

I get the over charge chatter from only one of my planes and it happens every time after a full charge. The servos that do this are high end JR digital servos. After one quick flight this condition goes away and doesn't happen again unless I give the battery a fast charge. That's pretty normal to see. Once flown it is gone. What is see with extensions is when they get dirty the servos start to lag. If not cleaned the problem can get very bad. I saw this at a lot of the IMAA giant scale events. A lot of the big planes don't get flown often and the owners forget or in my case are too lazy to be pulling servos just to clean the extensions. After seeing a lot of crashes of giant planes I started soldering wires to extend my servo leads and no longer have any problems, and I don't have to clean the critters. With Ys that are having a chatter problem it can be other problems, usually something wrong with the Y itself. I have never bothered to take a bad Y apart and test it to find out what the problem is so I can't say what is going on with them?
Old 04-19-2011, 09:36 AM
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Default RE: CRASHED plane due to servo chatter!! :>(

I use a Y-harness and extentions all the time and haven't had a problem. I only use JR and Hitec. I did once have a issue with a Y-harness that I took out of one of my crashed planes. ( Y-harness wasn't the cause) I put it in a new plane and when ever I gunned the throttle the ailerons started dancing uncontrollably. It took a while to find what was wrong, so I just replaced it with a brand new JR Y-Harness and she was good as gold. The problem: The Y-harness was pinched behind the glow tank causing a light short, and when I gunned the throttle- the vibration increased causing the servo's to dance. Make sure non of your wires was pinched. If you had a complete short or a broken wire, they would have not worked at all.

Digital Servo's like to dance a bit, but that's normal. I believe it wouldn't be the cause for your crash.


Pete
Old 04-19-2011, 09:54 AM
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Default RE: CRASHED plane due to servo chatter!! :>(

to me it sounds like you may have a bad cell in your RX battery and eventually you had a brown out. I do agree with Grey about extentions and Y's and never use them. 2.4 will not swamp the RX with signal and cause chattering, that is a 72 mhz thing.
Old 04-19-2011, 03:23 PM
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Default RE: CRASHED plane due to servo chatter!! :>(


ORIGINAL: speedracerntrixie

to me it sounds like you may have a bad cell in your RX battery and eventually you had a brown out. I do agree with Grey about extentions and Y's and never use them. 2.4 will not swamp the RX with signal and cause chattering, that is a 72 mhz thing.

That sounds logical.


Pete
Old 04-20-2011, 02:23 AM
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Kaos Rulz
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Default RE: CRASHED plane due to servo chatter!! :>(

I didn't pick up which he was flying - 72 MHz or 2.4 GHz.
Old 04-20-2011, 10:51 AM
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Default RE: CRASHED plane due to servo chatter!! :>(

With out knowing what he was on eveyone is just making a WAG
Old 04-20-2011, 11:53 AM
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Steve Percifield
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Default RE: CRASHED plane due to servo chatter!! :>(

he says spektrum 7 channel receiver, sos its 2.4.
Old 04-21-2011, 02:14 AM
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Kaos Rulz
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Default RE: CRASHED plane due to servo chatter!! :>(

AHHHyou're right. I missed that.

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