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Old 02-05-2009, 05:53 PM   #1
nick.gruber
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Default Trex 450 tail wobble servos twitching

a couple questions.
to start off, i had all my electronics in a belt cp, no problems with the electronics. I just got a Trex 450SA and put all the electronics in it.

i set up the gyro and brought it to a hover for the test flights. I notice the tail wobbles, so i decrease the gain and it still wobbles but less finely than when i increase the gain.

2nd problem, the servos twitch intermintitly (however you spell that). when in a hover they will cause the helicopter tip over unexpectantly. Ive inspected all the gears and they are fine.

Could it be static? I have all my servo wires and gyro wires bundled up and zipped tied under the gyro. the gyro is mounted in the back.

Or could it be the esc? it is the stock 35 amp esc. could it be sending too much voltage to the electronics?

Stock ESC
Stock 430L
hs 65hb (3)
ds290g (1)
Gy401
PCM JR Rx
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Old 02-05-2009, 06:27 PM   #2
RJ79
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It is probably because you have all your wires bunched together that is a no no, seperate the gyro wires from your servo wires and make sure your reciver and gyro wires are away from all power stuff like motor, esc, and any wires running from them. Since you are also running fm pcm make sure your antenna is away from motor wires and the wire running from your esc. Also make sure there is no binding or excessive slop in your tail and all tail linkages. Last thing to check make sure that the esc is NOT in governor mode the align esc is known to cause tail twitching when in governor mode. Sorry to thow all this stuff at you but the problem you are having could be caused by many things, best to check one thing at a time to figure it out.
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Old 02-05-2009, 06:30 PM   #3
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By the way what rx are you using jr770, 790?
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Old 02-05-2009, 06:37 PM   #4
nick.gruber
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Im running the 770. I appreciate the help. it just kind of has be boggled.
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Old 02-06-2009, 09:49 AM   #5
rcjpth
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Quote:
Originally Posted by RJ79 View Post
It is probably because you have all your wires bunched together that is a no no, seperate the gyro wires from your servo wires and make sure your reciver and gyro wires are away from all power stuff like motor, esc, and any wires running from them. Since you are also running fm pcm make sure your antenna is away from motor wires and the wire running from your esc. Also make sure there is no binding or excessive slop in your tail and all tail linkages. Last thing to check make sure that the esc is NOT in governor mode the align esc is known to cause tail twitching when in governor mode. Sorry to thow all this stuff at you but the problem you are having could be caused by many things, best to check one thing at a time to figure it out.
In my opinion, personal exp., I experience the same thing, I zipptied the gyro, servo together, and thee servos are twitching crazy, but on the bench, while testing when all lines are not tightened together, I got very good result (I use Futaba FM 6exh with 3 x Tower pro for cyclic, Align RX, Align ESC BL35G, Align 430L, Logictech2100 & 3100GS servo 0.07s/60 - almost the same with you Nick.)

But once I tightened them together, plugged in the RX and tested, it did the same thing like you described, I will pick up a AR7000 RX from my brother and will test it out this weekend.

I also have another bird, finished, and fly well but that bird has 3 x 65HB, 1 x 65MG tail servo and Telebee RCE-500X as gyro, 420L, Telebee Osteer 35A ESC - I tightened all the servo lines, gyro together, but no problem - however the only different I have for this bird with another is the TX/RX, I have AR6200 Rx & DX7 on this bird. I guess 2.4Ghz is way to go - it is one of main elements to eliminate the twitching I think.

Happy flying and will let you know my testing with AR7000/DX7

Tks,
Jake
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Old 02-06-2009, 07:56 PM   #6
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Originally Posted by rcjpth View Post
In my opinion, personal exp., I experience the same thing, I zipptied the gyro, servo together, and thee servos are twitching crazy, but on the bench, while testing when all lines are not tightened together, I got very good result (I use Futaba FM 6exh with 3 x Tower pro for cyclic, Align RX, Align ESC BL35G, Align 430L, Logictech2100 & 3100GS servo 0.07s/60 - almost the same with you Nick.)

But once I tightened them together, plugged in the RX and tested, it did the same thing like you described, I will pick up a AR7000 RX from my brother and will test it out this weekend.

I also have another bird, finished, and fly well but that bird has 3 x 65HB, 1 x 65MG tail servo and Telebee RCE-500X as gyro, 420L, Telebee Osteer 35A ESC - I tightened all the servo lines, gyro together, but no problem - however the only different I have for this bird with another is the TX/RX, I have AR6200 Rx & DX7 on this bird. I guess 2.4Ghz is way to go - it is one of main elements to eliminate the twitching I think.

Happy flying and will let you know my testing with AR7000/DX7

Tks,
Jake
When flying fm, electronics placement is crutial. I fly FM PCM and all my helis are all carbon, frames, booms, fins, and everything else is aluminum heads,tail cases, bearing blocks, etc (all the stuff the increases the risk of glitching in an FM system). So over time I have figured out perfect electronic setups for my helis, no glitching or any other probs. The main thing that HAS to be done is keep EVERYTHING seperated, all wires and components, and the most important KEEP ALL HIGH VOLTAGE POWER STUFF AWAY FROM RAIDIO GEAR this cannot be stressed enough, so keep the rx and gyro and all wires running from the rx, gyro and servos as far away as you can from motors, esc's, batteries, bec's. Pcm is fine for an electric heli as long as you follow these rules, now ppm should not be used on an electric heli, It can be done but the chances of getting gliching and other problems are much higher.
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Old 02-06-2009, 09:01 PM   #7
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I appreciate all the help guys. I fixed the gyro problem, after changing pinions, taking the tail apart, moving wires, etc. etc., i reversed the gyro and servo direction and now the tail locks in. I dont know what difference this makes but it works.

My servos still twitch even though i moved the wires. But i think they are just twitching when the battery is about to go dead. Im not sure if that has anything to do with it.

I think im running ppm or maybe pcm cant remember. but maybe its time to upgrade to 2.4
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Old 02-07-2009, 07:33 AM   #8
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Just wondering why you had to reverse the rudder channel and gyro, did you change the way they were mounted. If they were both the wrong way when you started out, that definitely would have caused major problems.

As far as the servo twitching, do you mean just the tail servo or all the servos? My tail servo twitches at the slightest movement of the heli, its the nature of the gyro to make corrections (rudder inputs) to keep the tail still so it might appear that its twitching but its supposed to do that.

IMO, 2.4Ghz is the way to go now-a-days.
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Old 02-07-2009, 07:38 AM   #9
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So I guess I should not have my LGG 1 Li-poly monitor stuck to the back of my receiver with the power wires running right next to my receiver!!! :o I will be doing some re-wiring today!! I will at least be able to put my new Hakko 936 iron to work.
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Old 02-07-2009, 08:05 AM   #10
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yeah i thats what it was. I had the servo on the otherside on my other heli and on this I had it on the reverse side. Still dont know what difference it makes, but I guess I dont understand gyros good enough.

The servos (all) only seem to twitch when the battery is about dead, for some reason, otherwise they work fine. Its just hassle, because if your flying around and battery is getting low the servos start twitching and helicopter acts a little erractic.
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Old 02-07-2009, 09:18 AM   #11
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Quote:
Originally Posted by nick.gruber View Post
yeah i thats what it was. I had the servo on the otherside on my other heli and on this I had it on the reverse side. Still dont know what difference it makes, but I guess I dont understand gyros good enough.

The servos (all) only seem to twitch when the battery is about dead, for some reason, otherwise they work fine. Its just hassle, because if your flying around and battery is getting low the servos start twitching and helicopter acts a little erractic.

You are flying your batteries to long if that is happening, your low voltage sensor on the esc is probably kicking in. Do you follow the 80% rule? If you are flying 2200 lipos you should take out no more than 1760mah, with 2100 lipos no more than 1680mah, or if 1800 lipos no more than 1440mah. If you are flying your batts longer than that you are greatly reducing there lifespan. Do you just fly until the LVC kicks in? If so you are ruining your lipos. By the way since you are using the JR r770 you are flying pcm.
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Old 02-07-2009, 09:55 AM   #12
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Actually, I found out im using the r700 rx. I guess it is only PPM and SPCM. If I put the TX in SPCM the servos act all erratic. So my only option is to fly PPM.

Is this bad?
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Old 02-07-2009, 02:30 PM   #13
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Quote:
Originally Posted by nick.gruber View Post
Actually, I found out im using the r700 rx. I guess it is only PPM and SPCM. If I put the TX in SPCM the servos act all erratic. So my only option is to fly PPM.

Is this bad?
That is your problem then. PPM and electric helis dont mix very well, you are experiencing glitching. I had the exact same problem when I was using the r700, when I put in some pcm rx's jr r790's all problems were solved. so if you dont want to spend all the money to switch to 2.4 just get a pcm rx like the jr r790 and all your problems will be solved
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Old 02-07-2009, 02:31 PM   #14
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With the r700 you have to fly in ppm because the r700 is not a pcm rx it is only a ppm.
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Old 02-07-2009, 03:28 PM   #15
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so i can get the r770 but i dont need a new transmitter. I can just use SPCM?
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Old 02-08-2009, 08:13 AM   #16
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yes sir, the jr r770, 790 has a button on it that will find your channel. So you just set your radio to spcm ( if using the r770 or 790) turn everything on and press the button on the 770 or 790 and you're locked in on spcm and no more glitches
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Old 02-08-2009, 10:09 AM   #17
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Quote:
Originally Posted by nick.gruber View Post
I appreciate all the help guys. I fixed the gyro problem, after changing pinions, taking the tail apart, moving wires, etc. etc., i reversed the gyro and servo direction and now the tail locks in. I dont know what difference this makes but it works.

My servos still twitch even though i moved the wires. But i think they are just twitching when the battery is about to go dead. Im not sure if that has anything to do with it.

I think im running ppm or maybe pcm cant remember. but maybe its time to upgrade to 2.4

Nick,
As I said I got the RX7000 from my brother and put it in the bird I had the twitching issue (believe it or not, while using Futaba 6exh with Align RX in this bird, while the helicopter on the ground, power on, and everything was quiet, the servo twiching when even I made any movement or even the motor was twitching sometimes...)

So I got RX7000, got it bound it to my DX7 - and amazingly, now NO MORE twitching and the bird is flying hella solid, tail holds YEAHHHH ROCK SOLID - Logictech 2100T 3100GS combo $109.99 shipping included Heliproz heheeheh (CX450AE, V2, Towerpro cyclic, Logictech2100&3100 combo - heliproz sells for 109.99 free shipping got it or stock will be clear!! LOL Align 430L, Align BL35G no governor, no brake, no softstart, throttle quick response, mid timing). For my case, I blamed Futaba 6exh & Align RX, they are the primary suspect and after I switched to 2.4, problem gone...

I hope someone will bid my Futaba 6exh & align receiver on the ebay....only 2.4 is way to go...Hope you find it helpful for your case

tks,
rcjpth
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Old 02-08-2009, 10:22 AM   #18
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Yeah i maybe going 2.4 here shortly, i guess this is a good excuse. I just didnt want to make the investment. Thanks for the help.
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