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600 Class Electric Helicopters 600 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


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Old 10-07-2009, 03:43 AM   #1 (permalink)
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Default Tail is twitching

I have a stock 600 ESP with Spartan and JR8900 Servo
Gyro gain is set to 59% and Iam running Turnigy 5000mAh 20C packs.

When I hover and do not alternate the collective the tail twiches abit from side to side.

What is the remedy for this, more or less gyro gain, or other solution?

Any answer greatly appreciated!
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Old 10-07-2009, 04:01 AM   #2 (permalink)
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Try less gain. Lower the gain until the tail no longer holds, then go up a tick.
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Old 10-07-2009, 04:21 AM   #3 (permalink)
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Quote:
Originally Posted by ollie2893 View Post
Try less gain. Lower the gain until the tail no longer holds, then go up a tick.
I will try that out. Thanks!
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Old 10-07-2009, 05:39 PM   #4 (permalink)
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I feel there are 2 issues with a tail.
1. Twitching (a small rapid swing in the tail
2. Wag (a slow swing in the tail

My 600e has developed a twitch which I believe could be Electrostatic discharge. But if the tail has a wag, then I would try adjusting the gyro gain.
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Old 10-07-2009, 07:30 PM   #5 (permalink)
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adjust your gyro first.

Harry
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Old 10-07-2009, 07:39 PM   #6 (permalink)
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You can check the ESD factor bu spraying a Q-tip with staic gaurd and wiping down the main, and tail gears with ti, then hold it against the tail belt through the fram and rotate the head until the belt has mad a complete revolution. If its static this will get rid of it for a while(the slow wag). It wont last long, at most a couple of flights unless you really soak it. I had a similar issue with my 500CF and this would cure it temporarily. If it cures the wag, then look into one of the static mods longer term.
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Old 10-08-2009, 09:11 AM   #7 (permalink)
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I cannot try anything right now because I wrecked my landing gear
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Old 10-08-2009, 09:15 AM   #8 (permalink)
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Is ESD a big thing on a 600 with torque tube? Ive heard that the 500 have problems..
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Old 10-09-2009, 06:37 PM   #9 (permalink)
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Are you using the stock electronics?
If you are you using the governer mode of the stock esc, than this could be the reason.
I had the same problem and I changed my esc and everything went normal.

Oskar
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Old 10-10-2009, 03:08 AM   #10 (permalink)
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Quote:
Originally Posted by mach1 View Post
Are you using the stock electronics?
If you are you using the governer mode of the stock esc, than this could be the reason.
I had the same problem and I changed my esc and everything went normal.

Oskar
No my friend said that gov is just hunting so its not enabled. Thanks for the hint though.
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Old 10-10-2009, 10:25 AM   #11 (permalink)
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Lowered gain all the way to 20%, no help.
Changed the position of the ball link in the servo lever arm, no help.
Tried 3 different power packs, no help.
Rerouted all wires, isolated gyro cables and motor cables, no help.

My theory either the spartan 760 is broken is broken or there is something from with the Align ESC causing it to bog/hunt and thus force the gyro system to do impossible corrections.

Btw at first flight there were no issus at all. This came on the third pack.

Any idea?
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Old 10-10-2009, 11:04 AM   #12 (permalink)
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You wrote that you do not fly gov mode? Then it should not be possible for a negative feedback loop to develop between gyro and esc. It is possible, just, that your motor is running "rough" in so much as that the esc's motor timing does not work to produce the silkiest run. Try setting motor timing to "high" to see whether it makes any difference.

Also, I might have missed the key words in this thread, could I ask you to recap:
- how violent are those twitches?
- what's the periodicity?
- is it a wag left/right around center? or does it kick out to one side and resets to center?
- what happens under max climb-out? at 20% you should really lose the tail...
- what happens when the gyro's switched into YR mode? (it may drift coz your tail isn't trimmed mechanically; but does it twitch?)
- what diameter tr are you flying? (I hadn't thought it matters unless the thing's soo small that the max travel of the gyro isn't enough to catch promptly.)
- is the tail slider perfectly smooth? (That is important.)
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Old 10-10-2009, 11:06 AM   #13 (permalink)
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PS: This is TT, right? Are you confident that the gear mesh is just so? That all the teeth are still on the various cogs?
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Old 10-10-2009, 11:50 AM   #14 (permalink)
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Ollie:

- how violent are those twitches?
2 inch to each side

- what's the periodicity?
cyclic, 1-2 seconds inbetween

- is it a wag left/right around center? or does it kick out to one side and resets to center?
it resets to the center

- what happens under max climb-out? at 20% you should really lose the tail...
at 20% we could still fly it but it didnt hold the tail

- what happens when the gyro's switched into YR mode? (it may drift coz your tail isn't trimmed mechanically; but does it twitch?)
I havent tried it..

- what diameter tr are you flying? (I hadn't thought it matters unless the thing's soo small that the max travel of the gyro isn't enough to catch promptly.)
iam not sure i understnad but i tried between 2,3,4 th hole on a standard servo arm.

- is the tail slider perfectly smooth? (That is important.)
its perfect..

Cogs are fine, good adjusttment of the gear mesh.
14 teeth pinion
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Old 10-10-2009, 12:21 PM   #15 (permalink)
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Ok, one more clarification please:
Quote:
Originally Posted by SwePilot View Post
(1) [it twitches] 2 inch to each side; and
(2) [it kicks out to one side and] it resets to the center
appear to contradict each other. Is it predictable that a left twitch will be followed by a right twitch, or could a left twitch be followed by another left twitch?

Incidentally, what happens on the ground? Say you spool her up but don't lift off. Just sitting there, does the tail twitch every 1-2 secs?
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Old 10-10-2009, 01:49 PM   #16 (permalink)
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Quote:
Originally Posted by ollie2893 View Post
Ok, one more clarification please:

appear to contradict each other. Is it predictable that a left twitch will be followed by a right twitch, or could a left twitch be followed by another left twitch?

Incidentally, what happens on the ground? Say you spool her up but don't lift off. Just sitting there, does the tail twitch every 1-2 secs?
Its unpredictable, just before take off rpm/pitch then the twiching starts.

Thinking of getting another ESC now.
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CC ICE 100, Hacker A40-10L 8 Pole Turbine Motor.
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Old 10-10-2009, 02:04 PM   #17 (permalink)
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Ok, now think hard about this question:
When you hover your bird, you will invariably constantly be adjusting collective (as the air flow changes) in order to maintain altitude. Could it be that the one-sided twitch that you see correlates to the collective instructions that you give? That is, could it be that a short stab up is followed by a twitch to the left, and vice versa?
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Old 10-10-2009, 02:22 PM   #18 (permalink)
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Quote:
Originally Posted by ollie2893 View Post
Ok, now think hard about this question:
When you hover your bird, you will invariably constantly be adjusting collective (as the air flow changes) in order to maintain altitude. Could it be that the one-sided twitch that you see correlates to the collective instructions that you give? That is, could it be that a short stab up is followed by a twitch to the left, and vice versa?

If I stab it it goes to the right.
What does that mean?
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600 MI 24 Hind Scale with 5 main rotor blades
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Old 10-10-2009, 03:18 PM   #19 (permalink)
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Is gyro placement important, its located on the little shelf in the back.

It used to sit more forward abit higher on the boom block or what it is called.. perhaps this could be something?
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600 MI 24 Hind Scale with 5 main rotor blades
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Old 10-10-2009, 03:18 PM   #20 (permalink)
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Well, let's think: you have a clock-wise rotor whose thrust force is opposed by a counter-clockwise torque vector. If you increase collective thrust you increase counter-clockwise torque ... and your tail should be expected to kick out to the right. That's what you would expect to happen if the tail is "loose", ie the gyro gain is too low.

So opposite recommendation: increase your gyro gain until your tail begins to oscillate around center (swinging left to right). Then back off a notch or two...
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