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Old 01-27-2019, 10:45 AM   #1 (permalink)
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Default Fireball Competition Tail Wag / Shake

Hi, I have my new Fireball up and going. I`m working on tail wag in hover. I think I have read all threads on the subject. I am wanting to run low headspeed for practice. At 3200, I have tail wag and an occasional tail jerk or jolt. I have been up and down on the gain to where it shakes and to where it won`t hold. I have tried without the governor also. At 3500, after adjusting gain, I have it down to just a calm wag at hover. The headspeed seems to help. I haven`t been any higher.

I am using a Mini Ikon2, BK servos, and the ball is at about 8mm on the arm.

I have 10 flights(hover) on it so far.
Would love some input on more things to try.
Thanks, Bill.
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Old 01-28-2019, 11:35 PM   #2 (permalink)
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Hi,

Take the tip of the tail boom and try moving it right to left/left to right and see if you have any play beetween the boom and the frame. If so, it helps to remove the boom, put some nice foam double sided tape on where the boom will come in contact with the frame. That will pad it and remove play, thus reduce vibrations to none.

Before, you should definitly try 4000 rpm. It will help alot, the Fireball adores high head speeds.

P.S I love my Fireball
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Old 01-29-2019, 08:22 AM   #3 (permalink)
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When you are up and down gains and wags don't behave it's usually mechanical. I would completely disassemble the tail and check:


1. Correct placement of small and large thrust bearing assembly.
2. Smooth movement of the tail slider along the shaft.
3. No binding on any part of the assembly.


If the tail mechanism is properly assembled and smooth then any wag should be easily tuneable. I don't have a Fireball I will admit but this is a basic principle that gets worse as you go down into heli size.
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Old 01-29-2019, 08:27 AM   #4 (permalink)
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Thanks for the replies. I will check all of the suggestions.

Was trying to use lower headspeed to keep it calm for orientation practice. It may not be possible though.
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Old 01-29-2019, 08:27 AM   #5 (permalink)
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I know you said you tried all sorts of gains, but this this: time After you get your P gain just below shaking, try really bumping up your D gain. That’s what ended up working for me on a 270 mm size.
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Old 01-29-2019, 09:55 AM   #6 (permalink)
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Quote:
Originally Posted by bclark View Post
Thanks for the replies. I will check all of the suggestions.

Was trying to use lower headspeed to keep it calm for orientation practice. It may not be possible though.
You need to read the posts about the tail wag.. there’s a few.. but for lower head speed, you need the speed up pulley. No gyro settings will work if the tail isn’t up to speed. Mine had a problem and the fix was where the thrust bearings went on wasn’t smooth. So rough that the outer race with the smaller inside dia would catch and get stuck. I polished where they go on. But the speed up pulley helped too.
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Old 01-29-2019, 10:03 AM   #7 (permalink)
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Quote:
Originally Posted by xoexoe View Post
I know you said you tried all sorts of gains, but this this: time After you get your P gain just below shaking, try really bumping up your D gain. That’s what ended up working for me on a 270 mm size.
Your comparing a blade heli to an oxy.. 2 completly different helis with different tail ratios. Each persons heli will have different settings for gain, tail, so what works for one, might not work for the other.
A common prob with the small helis is assembly problems that result in tail wags.. small interference fitment problems that need to be addressed from the builder.
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Old 01-31-2019, 05:51 AM   #8 (permalink)
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I will order the speed up pulley and will take the tail apart and check the bearing fit. It does feel good though.

I wondered about the pulley because the jerk goes away and the wag gets better at higher headspeed.

Today I'm going to try the ball moved out to 10mm. Don't look for it to help though.
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Old 01-31-2019, 08:07 AM   #9 (permalink)
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Quote:
Originally Posted by bclark View Post
I will order the speed up pulley and will take the tail apart and check the bearing fit. It does feel good though.

I wondered about the pulley because the jerk goes away and the wag gets better at higher headspeed.

Today I'm going to try the ball moved out to 10mm. Don't look for it to help though.
Actually moving the ball helped to find the best position for the rpms that your running. Either in or out, it’s just trial and error. But do it after the speed up pulley is installed and your running the head speed you like and tune from there.
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Old 01-31-2019, 02:06 PM   #10 (permalink)
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I got a test hover in with the tail servo ball moved to 10mm and saw no change at all.

Also, the tail boom seems to fit good and is tight.
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Old 01-31-2019, 04:28 PM   #11 (permalink)
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another thing that helped me was the lynx/kst tail servo.

https://www.lynxheli.com/product_inf...fb068005db73e0
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Old 01-31-2019, 06:13 PM   #12 (permalink)
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Quote:
Originally Posted by tonys-heli View Post
another thing that helped me was the lynx/kst tail servo.

https://www.lynxheli.com/product_inf...fb068005db73e0
Are you flying a Fireball or an Oxy?
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Old 01-31-2019, 06:21 PM   #13 (permalink)
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Quote:
Originally Posted by bclark View Post
Are you flying a Fireball or an Oxy?
i had a fireball.. i have both a oxy 3 and 4.
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Old 01-31-2019, 07:06 PM   #14 (permalink)
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Quote:
Originally Posted by tonys-heli View Post
i had a fireball.. i have both a oxy 3 and 4.
For some reason I`m not getting email notification.

Did you try that servo on the fireball?
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Old 01-31-2019, 11:53 PM   #15 (permalink)
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yes, worked great.
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Old 02-06-2019, 04:45 AM   #16 (permalink)
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I got the speed up pulley installed. Didn't see any change at 3200, it still had the irregular jerk and the slow wag.
At 3500, it seemed to be a little better. I went up on the gain till I got the fast shake and then backed down. Now it shakes on hard tail stops. I guess maybe I need to be adjusting on one of the other gains for that?
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Old 02-06-2019, 05:50 AM   #17 (permalink)
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move the ball in one hole and re set your end points. are they over 100 travel?
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Old 02-06-2019, 08:32 AM   #18 (permalink)
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I set the tail travel in the ikon software.
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Old 02-06-2019, 09:11 AM   #19 (permalink)
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Quote:
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I set the tail travel in the ikon software.
Yea, but move the ball in one hole,Then reset the travel and see how it does. That way your changing the resolution. You’ve done a lot of tuning with the speed up pulley, now you have the head speed up so you have to start back at the servo. Sounds like it has too much mechanical gain, meaning it’s too far out on the servo.
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Old 02-06-2019, 10:37 AM   #20 (permalink)
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Quote:
Originally Posted by bclark View Post
I got the speed up pulley installed. Didn't see any change at 3200, it still had the irregular jerk and the slow wag.
At 3500, it seemed to be a little better. I went up on the gain till I got the fast shake and then backed down. Now it shakes on hard tail stops. I guess maybe I need to be adjusting on one of the other gains for that?
I believe D gain will affect tail stop.
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