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Old Jan 02, 2013, 08:09 PM
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My servo suspicion has to do with a right roll crash that I had last spring.

The heli was in idle 1 about 15ft off the ground and without warning the heli rolled over to the right and planted itself about 2" into the soft ground. At the time I attributed it it static but, the weather that day was cool and humid (slight mist in the air) which is a very hard environment to build a static potential and subsequent discharge.

All of the servos survived that crash but I have noticed ever sense that pitch isn't always consistent with all 3 cycle servos and when movements get aggressive, it feels like the right cyclic servo isn't reacting the same as the others. It could be that with the DFC head, their isn't enough torque? My theory expands to the gyro trying to compensate for the servo issue and the result is the bouncing followed by the shuttering that happens avery couple of seconds.
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Old Jan 03, 2013, 10:18 AM
just gotta mess with it!
2Doggs's Avatar
North West Louisiana
Joined Nov 2009
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If you're feeling experimental, you could swap out the servos to move the bad one to elevator, to see if the control glitch moves with it. It sounds like you should replace the servo though.
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Old Jan 03, 2013, 04:24 PM
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United States, WA, Issaquah
Joined May 2011
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Yep, the Gotek's are only spec'd for 80Hz refresh rate.
http://www.hobbyking.com/hobbyking/s...g_0_07sec.html

As far as I'm concerned, they are not suitable for use on any function for any helicopter
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Old Jan 03, 2013, 04:39 PM
just gotta mess with it!
2Doggs's Avatar
North West Louisiana
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I suspect HK have changed the spec in their description as a result of so many people reporting problems. My own experience is that the Gotek can be coaxed to run at 333Hz, but you have to keep a watch on temperature, and set the gain accordingly, all the while making sure that there's no binding in the linkage. Mine still works after more than 50 flights on the tail of one of my 450's, and to be honest I only bought it to see if it was really as bad as everyone made out. It's definitely a trap for the unwary, and there are lots of better servos at comparable prices.
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Old Jan 03, 2013, 04:57 PM
Chris
The Netherlands, NB, Eindhoven
Joined Sep 2010
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Quote:
Originally Posted by 2Doggs View Post
I suspect HK have changed the spec in their description as a result of so many people reporting problems. My own experience is that the Gotek can be coaxed to run at 333Hz, but you have to keep a watch on temperature, and set the gain accordingly, all the while making sure that there's no binding in the linkage. Mine still works after more than 50 flights on the tail of one of my 450's, and to be honest I only bought it to see if it was really as bad as everyone made out. It's definitely a trap for the unwary, and there are lots of better servos at comparable prices.
Suggestion please?
I've also fallen in the "trap" but my tail seems ok.. (450)
Would be good to have a good replacement though.
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Old Jan 03, 2013, 07:08 PM
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ahamay's Avatar
Australia, QLD, Gold Coast
Joined Jun 2012
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Originally Posted by cmavr8 View Post
Suggestion please?
I've also fallen in the "trap" but my tail seems ok.. (450)
Would be good to have a good replacement though.
I can highly recommend the TGY-S306G from hobbyking as a rudder on a 450. I've got them on both my PRO's and they are outstanding.

http://www.hobbyking.com/hobbyking/s...06sec_21g.html
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Old Jan 04, 2013, 07:05 AM
Chris
The Netherlands, NB, Eindhoven
Joined Sep 2010
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Thanks, so the extra torque of the Goteks is uneeded at a 450, right?
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Old Jan 04, 2013, 09:49 AM
just gotta mess with it!
2Doggs's Avatar
North West Louisiana
Joined Nov 2009
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The Gotek and pretty much all of the 9257 clones have enough torque to easily bend the tail pitch control rod on a 450, and they're man enough for a 500 tail. The 306 has enough torque to be used on 450 cyclic, and is perfect for the tail. The only downside is that it's a mini servo, and you need to use an adaptor to fit it onto the 450 Pro tail servo mount. When used on 450 cyclic, the downside is it's a bit heavy compared to the average mini servo.
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Old Jan 04, 2013, 07:44 PM
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Thanks for the responses. I will work a little more on the heli tomorrow. Not much work in that regard happens during the work week this time of year (working dark to dark).

I will replace rx tomorrow and also check all wiring for any issues. Also need to recheck the gyro settings on the PC because I am also thinking I may have the gain set to high. And I will also start researching other servos to replace the cyclic servos.
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Old Jan 05, 2013, 02:10 AM
Chris
The Netherlands, NB, Eindhoven
Joined Sep 2010
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Quote:
Originally Posted by 2Doggs View Post
The Gotek and pretty much all of the 9257 clones have enough torque to easily bend the tail pitch control rod on a 450, and they're man enough for a 500 tail. The 306 has enough torque to be used on 450 cyclic, and is perfect for the tail. The only downside is that it's a mini servo, and you need to use an adaptor to fit it onto the 450 Pro tail servo mount. When used on 450 cyclic, the downside is it's a bit heavy compared to the average mini servo.
I guess it will pay off if used in a FBL setup though...

Thanks for the suggestions

Chris
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Old Jan 05, 2013, 03:20 PM
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Turns out its a bad servo. I had originally thought it was the right servo but turns out its the left. I caught it when reviewing the gyro set up where I noticed it didnt move right away to a stick command. Further review and testing resulted in no movement unless forcibly coaxed in the proper direction.

I have a spare but I will also look for a good replacement set. The hitec digitals look to be a good value and I have seen some good reports on the bluebird servos as well.

Oh, and I just got it back together and guess what; just started to snow....like a dang blizzard out there. It was nice and sunny and calm this morning with temp about 32f...
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Old Jan 05, 2013, 03:52 PM
just gotta mess with it!
2Doggs's Avatar
North West Louisiana
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With the 9257 clones, it's often the motor that fails in that way - the servo won't move until you nudge it. You can fix it by replacing the motor, but that's rarely worthwhile on cheap servos.
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Old Jan 05, 2013, 04:35 PM
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Quote:
Originally Posted by 2Doggs View Post
With the 9257 clones, it's often the motor that fails in that way - the servo won't move until you nudge it. You can fix it by replacing the motor, but that's rarely worthwhile on cheap servos.
Servo also started jittering. Either way, it doesn't work. Time to look for a nice set of cyclic servos.
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Old Jan 05, 2013, 05:27 PM
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Align 510s have served me well on two different 500s. They can be had pretty cheap for set in the classifieds.


Dave
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Old Jan 05, 2013, 05:30 PM
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Thanks Dave, I'll keep a lookout.

Break in the weather. Got a couple fo test flights in and Everything seems to be working very well for the moment.
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