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250 Class Electric Helicopters 250 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


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Old 10-13-2010, 03:54 PM   #1
Steve Joblin
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Default Still a wag :( New gyro, New Tail Servo, or both?

I have tried everything... and I mean EVERYTHING and I still have a tail that wants to wag and wander when all I am doing is simply hovering four to five feet off the ground. My headspeed is set to 90%. I have tried a complety new tail assembly, a kevlar belt, CF Tail Pushrod, large tail blades, small tail blades, etc. etc. etc.

I can't believe that the Align GP780 Gyro and Align DS420 Tail Servo that came with the SE Super Combo kit are not up for the job, but I have heard that everyone keeps saying that they replaced theirs.

I don't mind spending a few dollars on new parts to try to fix the problem but I really don't want to spend hundreds of dollars on a new gyro and tail servo only to find out that I still have a tail wag.

Do you think I should get a new gyro?
Do you think I should get a new tail servo?
Do you thinki I should get both a new gyro and servo?

What are the best recommendations for a pilot who can't even do 3D (yet)?
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Old 10-13-2010, 04:03 PM   #2
Ah Clem
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1) Do you have the metal tail rotor control arm? It is slightly longer on the input side and does not flex.

2) Have you gone through the tail pitch change mechanism and made sure that the tail pitch change movement is completely smooth?

3) Which version of the tail blade grips do you have? No Chinese weights, small Chinese weights, large Chinese weights?

4) Which tail blades are you currently using?


I am using a JR 3500G tail servo-it is large, but works extremely well.

Up until last week, I was using a Spartan 760 tail gyro, that worked very well (a Quark of a GY520 would probably be a better choice due to their smaller size).

The Spartan with the JR 3500G and KBDD Tail Blades held the tail quite well. The Microbeast is holding the tail even better (with the same servo and tail blades).
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Old 10-13-2010, 04:30 PM   #3
Steve Joblin
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Quote:
Originally Posted by Ah Clem View Post
1) Do you have the metal tail rotor control arm? It is slightly longer on the input side and does not flex.
I have the plastic one... I guess I can stop over the to the LHS and get one.


Quote:
Originally Posted by Ah Clem View Post
2) Have you gone through the tail pitch change mechanism and made sure that the tail pitch change movement is completely smooth?
I have gone through it many times... silky smooth... no binding anywhere.


Quote:
Originally Posted by Ah Clem View Post
3) Which version of the tail blade grips do you have? No Chinese weights, small Chinese weights, large Chinese weights?
I have the ones that came in the kit... they are marked as 25T044A New Metal Tail Rotor Holder. I don't have any chinese weights.

Quote:
Originally Posted by Ah Clem View Post
4) Which tail blades are you currently using?
I've tried the small batwings, large batwings and 42 straight cut... none seemed to make any difference.

Quote:
Originally Posted by Ah Clem View Post
I am using a JR 3500G tail servo-it is large, but works extremely well.

Up until last week, I was using a Spartan 760 tail gyro, that worked very well (a Quark of a GY520 would probably be a better choice due to their smaller size).

The Spartan with the JR 3500G and KBDD Tail Blades held the tail quite well. The Microbeast is holding the tail even better (with the same servo and tail blades).
Thanks for the gyro and servo suggestions!
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Old 10-13-2010, 04:49 PM   #4
craig303uk
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u should try a HK401b mines holds very well no wag or drift, i was planning on buying something a bit better as i thought it would be no good but i think i'll hold off for a wee while as this is doing the job for me at the moment.
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Old 10-13-2010, 04:52 PM   #5
Ah Clem
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This is the version of the tail rotor blade grips that I installed (having no luck with the originals):

New Metal Tail Holder Set H25095A:

http://www.alignrcusa.com/index.php?...oducts_id=1396

Metal Tail Rotor Control Arm H25092:

http://www.alignrcusa.com/index.php?...oducts_id=1222

My incredibly biased choice of Tail Rotor Blades:

KBDD Tail Blades: 200/250 4065 Neon Yellow 40mm tail blades
200/250 4066 Neon Green 40mm tail blades
200/250 4067 Neon Orange 40mm tail blades
200/250 4068 Midnight Black 40mm tail blades

http://www.kbddintl.com/product.php#tail

The tail was absolutely terrible on my Trex 250 (it was a very early kit-things are much improved now). Now the tail holds well (with the BeastX, almost as well as the tail on a Trex 450 SE).

The distance of the ball to the center of the arm on the rudder servo is critical (I moved it in about three times). If Align had made the tail control arm longer (about 1/4" longer), I think a larger percentage of these issues would have gone away.

Let me know how it turns out.
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Old 10-13-2010, 05:06 PM   #6
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Steve, Before you spend any money on it, add full delay in the 780. I have an older version with the 750 on it, it took a month for me to fix the wag. My buddy has the newer version like you, he had to add full delay in the 780 to fix his problems and now he can do hard 3-D with no problem.

If that doesn't fix it, get a new tail servo, I put the DS290 on mine.

Hope this helps,

Craig
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Old 10-13-2010, 07:01 PM   #7
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heya steve, don't buy any more stuff, what you have is fine. You just need to look what needs adjusting or repositioning. I've got the stock hk250 plastic version v1! I have no align parts on it, what so ever. But I did had to adjust the slop in the tail, adjusted the tail slider travel so there is no binding, I also had my tail belt slightly loose, I adjust anything else that had slop or binding, I repositioned the hole on the tail servo horn to the inner most hole. everyone tells me I should use the align feathering shaft, main shaft, tail gear assembly. What for? Mine is working fine. But I did pull out everything and threadlock them all. Took about 2 weeks to do it properly. With 68% GAIN the tail is solid. I just gotta learn how to fly.


HK250 v1(plastic version):
mystery gyrd gyro(aka hk401b)
turnigy ds480 (tail servo)
hxt900(cyclic servos)
ff200 motor 5000kv (no name brand motor)
HK 30A ESC
Walkera 2801 RX
Plastic Main Blades
Plastic Tail Blades


P.S I created a plastic tail push rod( I don't think that does anything, but it looks cheap) and I did change the tail drive gear, with an hk250gt tail gear, because I was experimenting and this bird couldn't handle 5000 HS. I went over the recommended setup. I think I am still over it slightly, my current HS for this bird is 4200. Be patient steve, keep looking at it, adjust or threadlock , what's needed, I know how you feel.
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Old 10-13-2010, 07:14 PM   #8
Steve Joblin
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My servo ball is on the closest hole to the center of the arm.... 4.5mm (I think).

My tail mechanism is quite smooth... no binding. There is a bit of play, but I wouldn't call it "slop" per se.

Interesting that Ozz thinks I should add full delay... everyone and the manual says to have no delay. I'll give it a try though... nothing to loose.
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Old 10-13-2010, 07:25 PM   #9
pitchp
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are your blades balanced properly? are they tracking? man my 4g3 is not as picky as my 250, but my 4g3s are more squirrely just a bit. I could fly with unbalanced blades, and the tracking could be off on my 4g3, but my 250 wants everything to be perfect. talk about fussy. mind you the 4g3 has a tail motor.

I oiled everything! Tail slider, grip holders, bearings, the main shaft, I then cleaned off the excess oil with cotton buds.
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Old 10-13-2010, 07:27 PM   #10
Ah Clem
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"Interesting that Ozz thinks I should add full delay."

I would certainly try it.

Please post the results.

If that cures it, he and you will have helped quite a few people!
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Old 10-13-2010, 07:42 PM   #11
pitchp
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If it makes you feel any better steve, I'll swap you a brand new mystery gyrd gyro(hk401) for your gp780.
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Old 10-13-2010, 08:28 PM   #12
Steve Joblin
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Blades (both main and tail) anre balanced. Everything is lubed and smooth.

My 4G6, while it is quite "touchy", has a tail that stays where you put it.

Let me get back to you on the gyro swap

I'll test "full delay" tomorrow and post my findings.
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Old 10-13-2010, 08:55 PM   #13
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lol. On a serious note, once you figure out the art in building a stable 250, you can build any electric heli, aslong as their parts are of good quality! Steve do you know where I can get kevlar belts, i've got the crappy ff200, the belts are crap. I've got one belt that is working really good, but in general they are crap. I've mastered the tail on all my helis, unfortunately i can't do anything about the quality of the belt for the Firefox 200s. any idea where i can get a kevlar for this crappy bird?
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Old 10-14-2010, 12:32 PM   #14
Steve Joblin
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There are a few places that you can get the Kevlar belt...

Infinity Hobby: http://www.infinity-hobby.com/main/p...oducts_id=4560

RCHobbyHelicopter: http://www.rchobbyhelicopter.com/sto...licopter_Parts (third item from the bottom of the page)
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Old 10-14-2010, 01:46 PM   #15
Steve Joblin
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Well it seems that adding 100% delay didn't get rid of my tail problems, but setting it back to 0% delay did have an impact... and a positive one at that! My tail is much much much better than before, but still not "perfect". Really weird... Not quite sure, but it seems that the gyro didn't program correctly at first. I'm greatful to all your help, ideas, and suggestions! It still isn't holding like my 4G6 does, so I don't think my problems are completely solved, but at least I am in a much better place than I was before! Many thanks again Ozz!!!
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Old 10-14-2010, 03:31 PM   #16
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I just have to ask for a comparision here. After all the settings that I could come up with, sticking with the stock motor, servos and tail assembly, I'm down to about 1/2" occassional wagging. Especially when flying sideways, or doing side flips. Tail locks after piros nicely. Is this better or worse then what you have? Because I'm not worried too much about this occassional 1/2" wagging, but if you could go down much less than this, I'll just get a better servo to start with.
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Old 10-14-2010, 03:49 PM   #17
Steve Joblin
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1/2" frequent but not totally constant and consistent wagging while hovering is how I would describe my situation now... it is sort of like an "erratic" wagging. I haven't even gotten to FF, loops, rolls, or even 3D yet... I'm still focused on getting it perfect during a simple hover before I take the next step.
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Old 10-14-2010, 05:07 PM   #18
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Quote:
Originally Posted by Steve Joblin View Post
There are a few places that you can get the Kevlar belt...

Infinity Hobby: http://www.infinity-hobby.com/main/p...oducts_id=4560

RCHobbyHelicopter: http://www.rchobbyhelicopter.com/sto...licopter_Parts (third item from the bottom of the page)

Thanks SJ

also if you are planning to get a faster tail : http://helifreak.com/showthread.php?t=237646
The faster the better, Torque is all the same.
But the main thing is compatibility with that gyro, that is what you want to know before buying one. I can't recommend the ds480, because it works with certain gyros, and i am not sure if it will work with yours good luck SJ.
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Old 10-14-2010, 06:09 PM   #19
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My first 250 SE came with the Align 750 gyro. I ran a JR g290 on the tail, and had NO issues. My new 250 SE came with the 780 gyro. I'm also running the 290 on this one as well. I don't have a wag, but it certainly doesn't stay locked in like my first SE. I tend to believe that the 750 may be a better performer for this little guy. The 780's on my bigger birds work just fine. If I had the coin, I would get a Quark.

Stu
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Old 10-14-2010, 11:03 PM   #20
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dunno if you have this but add a carbon fiber push rod.
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250 Class Electric Helicopters 250 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.

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