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Main Forum - Helicopter Talk R/C Helicopters and the people who fly them. VENDOR TOPICS DO NOT GO HERE. Full Scale Heli threads go in OT please |
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06-20-2010, 09:56 PM | #1 (permalink) |
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Join Date: Oct 2008
Location: Midland, Michigan
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Anyone had this happen with a servo?
Yesterday, flying my Fury 55, the heli experienced an elevator glitch. As soon as I saw it - I was leveling off from a sweeping turn - I began to level off to a hover and land. Before I could get it down, the main rotor slowly went over and I had no elevator control to fight it. It hit the runway sort of inverted. When I arrived at the crash location, I found the elevator servo was full travel down - I believe it back flipped which would make sense. It appeared that the potentiometer was failed. It would not recenter after powering back up. Everything else seemed fine. I did find a single long link from the swash to main grip lying on the runway next to the heli - but I assumed it was popped off by the impact. It wasn't cracked or anything. I can do some more checking of the servo from another channel, but believe the servo simply failed. It was a new Align DS610. I have not previously read any significant issues with these. Prior to that, the bird flew perfectly.
Thoughts?
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06-20-2010, 10:06 PM | #2 (permalink) |
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i dont have those servos, but i have had two servos in the last two months fail pretty much like you have discribed.
i move the stick and the heli would just jump in one direction, it didn`t matter what i did it would just crash. i narrowed my issue down to a badly binding washout base and a swashplate eating itself. |
06-20-2010, 10:08 PM | #3 (permalink) |
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Join Date: May 2010
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Have you tore down the servo to see what it looks like inside ?
I had one years ago do something similar to yours and it had stripped about half of the teeth off the first gear coming from the motor. Just enough to cause it to move to one end of the travel. P.S. It was a Futaba servo
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06-21-2010, 04:46 AM | #4 (permalink) |
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I’ve had two 450 elevator servos do that to me before – one of them nearly took my “head off” when it moved to full down elevator and stuck there. Yeah, I know I was a noobie and flying too close to my face – I’ve never made that mistake again.
Like all electrical components, servos do fail and it is best to be safe and expect it to happen. |
06-21-2010, 09:13 AM | #5 (permalink) |
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Ive seen that three times in maybe four years of flying, with hs65mgs, where the servo arm goes full down when it fails, either intermittently, or it flatlines.
I just had a very minor crash, no damage, but when I reinitialized, I moved all the servos to check everything, and the aleron servo went full down and the esc began heating. It was very hard to move the arm, heavy resistance. Very important I think when this happens to unplug right away. The time before that, I had a 450 do an uncommanded right roll in idle 2, and go in on the head. Bunch of stuff was broken including a link, jesus bolt and so forth, and so I thought a link let go or bolt let go. So I fixed it, put it up all is good, go to idle 2 and right roll but I managed to hit thott hold and right it and get it down pretty much ok. It wasn't until I ran it up on the bench and went to idle 2 that I figured out it was the servo going full down at 100 flat thrott every few seconds or so. New servo. Certainly if you have any kind of crash you need to check your servos before lifting off again, or if you have any uncommanded movements, I'd go right to the servos and check it out.
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"The Great Santini" Futaba 8FHGS; Logo 600 3D FBL:, 4035-500, 12T, 12S, Jive80+HV, Futaba 6203SB, Fullsize V-Bar 5.1pro (Vergnugenstabi), BLS 451+251; Align 500esp: TracX FBL, 14T, ICE75, Beastx v3 |
06-21-2010, 10:08 AM | #6 (permalink) |
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.. same here, ive had it happen a total of 3 times since i started into helis, and ive had servos go glitchy where they would jump at a certain horn angle maybe 5 times .. the culprit in every single case? a hitech servo .. im sure it can happen to other brands to but the odds in my case are just against hitech futabas have been extremely rliable for me over the years even way before helis and my new servo love for the time being is inolab and so far those have been reliable ..
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06-21-2010, 11:07 AM | #7 (permalink) |
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I had 2 stock pitch servos fail on a b400.Both ended in a crash.The first one twitched a couple flights before it failed,should have listened to the heli.The second failed first flight with no warning,switched to quality digitals and have had now issues since.
Knock on wood. |
06-21-2010, 06:07 PM | #8 (permalink) |
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Join Date: Oct 2009
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Had a cyclic servo ( hobbyking mg-14) do this when i was still just learning to hover my clone 450. Got lucky. HS was still low and i flipped th in time. Heli landed inverted in the thick snow without much damage.
Turns out to be a wire breakage between the pot and cirquitboard, It was not broken loose, but had an internal fracture. I have become really anal about checking and vibration-proofing servo's. I open them up, check all the soldering with strong magnifier, resolder the servo leads if they dont look 100% and use heat glue on all the wires. The only other servo that failed was the one i didn't check. QC is lacking severely in China. |
06-21-2010, 07:24 PM | #9 (permalink) | |
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Quote:
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T-Rex 450 Pro FBL ZYX,T-Rex 700 Nitro FBL BEASTX,T-Rex 700 Nitro FBL BEASTX Spektrum DX8,AMA#849731 |
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06-21-2010, 08:05 PM | #10 (permalink) |
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Location: Midland, Michigan
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I did open the servo for a look last night. No stripped gears. All metal, and without any evidence of a problem. There's no mechanical damage that I can see. I think somehow the potentiometer failed like one person's observation (if I understood correctly). It does seem overall with the volume of servos from Futaba, and from JR, they are both highly reliable. I have a set of JR8717's on my Outrage 550 and they are superb, but do have a bit of slop. I the right conditions, I can feel they don't perfectly center, but it's really not a problem. I am at least confident in them, although my flying buddy has had trouble with them too. The new Futaba BLS servos are pricey, and one responder here noted a problem. I think only the elevator servo was damaged. The others behave fine. I am apt to think I like the 8717's if for no other reason than I can get excellent customer service from Horizon.
I was afraid perhaps I cheaped out too much using the DS610's...most are having no problems. Bought them from Grand RC as a combo pack...great deal. They are askign me to return it for examination. I bet they will replace it, but I'm not sure I want to wait until I can cycle it back to home base to be without the bird. Thanks all.
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06-21-2010, 08:08 PM | #11 (permalink) |
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I had a DS610 burn up on me during my VBar maiden.... after 300+ flights it gave up, and almost completely destroyed my Logo... i was less than thrilled. I still don't know why it burned up. The heli had never been crashed or even had a hard landing up to that point. I am very nervous about the other ones.....
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06-21-2010, 08:30 PM | #12 (permalink) | |
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I'm glad to see they want to look at the bad one and may replace it thats good service I think, if you get something in the mean time to fly with pick one you can use with another bird until you get the bad one replaced ? JMO
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Helicopter: A mass of parts, all trying to kill you since the day it left the factory ! |
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06-22-2010, 12:30 AM | #13 (permalink) |
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servo chirp
Lately while flying I notice that one of my servos on my heli will chirp and then heli twitches left to right . Is this a sign my servo is dying ? I am suspecting the elevator servo as it has been buzzing lately.
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06-22-2010, 08:40 AM | #14 (permalink) |
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Well, as it turns out, my other bird is a T-Rex 600N LE, which came with DS610's. Buying another DS610 would make for a spare if Grand RC comes through. Unfortunately, there's no predictability or detectibility to this problem.
Turko - I think the chirp sound is telling you something. Unfortunately, mine made no such noise. Just made for a spectacular crash. Of note - the Fury took it really well. Only inexpensive parts (other than the blades) damaged.
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06-22-2010, 08:58 AM | #15 (permalink) | |
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Any weirdness from a servo and I change it out, it;s just not worth the risk to me.
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Helicopter: A mass of parts, all trying to kill you since the day it left the factory ! |
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06-22-2010, 09:03 AM | #16 (permalink) | |
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Glad to see the Fury is up to the task, I'm thinking of getting one now Ive heard good things about it and I love the tail rotor design.
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06-23-2010, 07:27 PM | #17 (permalink) |
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DS410M same issue!! Brand new WTF?!
I've had the same issue on my 450 clone. The same servo location failed twice. My original DS410M performed fine for well over a year now, until about 2 weeks ago when it failed on spool up and tipped the heli over. TODAY I go flying to work on my flips and rolls and the brand new replacement with 5 flights on it failed mid roll. Went into a nice little inverted funnel which I then realised I couldn't recover from CRAP! TH saved it from too much damage. What I wanna know is why has this same thing happened to two servos? Could there be a volatage spike or something through the Rx. Using a Spektrum AR6100 and DX6i . Somebody help
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06-23-2010, 08:19 PM | #18 (permalink) |
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As I stated before I'm a noob returning to the hobby after a long hiatus. In the past I never heard of so many servo problems.
So I'm wondering... Are we asking to much of our servos? I know that increased voltage is a current "fad" and I'm thinking that has to take a toll. But, for those running the "correct" voltage, it seems like there are still quit a few faliures.. I think I've only lost one servo in 30 years of flying R/C. Of course I've been inactive for the last 6 or 7 years Any thoughts from the collective?
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06-23-2010, 11:05 PM | #19 (permalink) |
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Rob 43. I had the same problem with two of my DS610. Changed to Hitech.
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06-24-2010, 12:36 PM | #20 (permalink) | |
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Quote:
Just a guess but I don't think it's a voltage problem, we used to run 6 volt packs to get a little more torque out of the servos and to spin the mechanical gyro's faster i.e. make them more sensitive. With all the B.E.C.'s and regulators they have today it seems like good protection from overvoltage. Now I agree that we may be asking to much of them in the size or quality, micro servos are tiny meaning they also have very small parts if you cheap out on the quality of the potentiometers it could fail. Today all the disc force is applied directly to the servos via CCMP no bellcranks to take up some of the pressure, also if you look at some of the bigger heli's allot of people are using metal servo arms there has to be a reason for this ! So if you strengthen up the gears (metal) then do the same for the arms something has to give thats why they make servo savers. Is this correct or have some of the company's just gone the way of disposable products ? I'm not sure but it does seem to happen way to frequently. Just a thought from an old guy. P.S. Maybe I'm wrong here but the way I always looked at it was if it requires a 40 in.oz servo I will use an 80 in.oz. or 60 in.oz. minimum, better to have more than you need than not enough !
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