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700 Class Electric Helicopters 700 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar. |
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02-22-2015, 05:29 AM | #1 (permalink) |
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Join Date: Jul 2014
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Rex 700e dfc hv ovb problem?
Hi Guys
I recently build an t-rex 700e dfc hv frame witch I bought used. Everything went great during maiden but when I set up Govenor mode on my cc edge 120a and flew it again I ran into some problems. On normal mode (1550 rpm) everything is fine but as soon as I go to idle up 1 (1850 rpm) during pitch pumps the heli shakes and there's a sound like something's skipping. I checked all the gears and everything looks fine except the ovb. I made a vid of the ovb. https://www.youtube.com/watch?v=MoxG...ature=youtu.be Please help |
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02-22-2015, 05:37 AM | #2 (permalink) |
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Join Date: Jun 2014
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It looks ok to me. There is a gap to allow mashing. Ur problem as I guess is elsewhere. What kind of vibration you get? What head and fbl units u use?
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02-22-2015, 06:48 AM | #4 (permalink) |
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Join Date: Jun 2014
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HI,
It's important to know how it shakes. (Tail / head shake usually caused by fbl unit (gain) ). Then you can estimate the cause. If you say that without governor there are no issues, maybe the governor isn't set right. Can you save and post the CC configuration. (Its a .dat file). |
02-22-2015, 07:04 AM | #5 (permalink) |
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Thread Starter
Join Date: Jul 2014
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Tail seams allright. It's crisp and holds in rainbows. But as soon as head speed increases then the problem becomes more visible. I think the head speed during maiden was to low to expose the problem. Here's the govenor setting.
Only thing that I couldn't get right when I was setting govenor is, because I'm running spektrum dx6 I can't get decimal numbers as throttle curve. It's 50 for 1600rpm, 60 for 1850rpm and 70 for 2150rpm. |
02-22-2015, 07:49 AM | #6 (permalink) |
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It's been a while since I used the CC gov as I now use the vbar gov on my heli's but I would change your gov setting to "set RPM" rather than "gov high" I think doing that will enable it to hold the head speed better.
If you use set rpm then you don't need to wory about the decimal points, just set your curves at 30 70 and 100. I have heard that there can be a problem with the OWB slipping in high torque conditions, you will hear it slipping in flight, I don't think there is any way of testing it on the bench, I've never had that problem myself though.
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Velos 880 Neo, Logo 800 XX Vbar, T-Rex 800 Pro DFC Vbar, T-Rex 800 Trekker Vbar, T-Rex 700 Pro DFC Vbar, T-Rex 800 F3C Vbar, T-Rex 550E DFC Vbar, T-Rex 500 Pro DFC AR7200BX, T-Rex 450 Sport V2 AR7200BX, T-Rex 250 Pro AR7200BX, VController, DX9. |
02-22-2015, 11:26 AM | #7 (permalink) |
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Join Date: Apr 2012
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There are some good videos on the CC web site for setting up the end points and governor.
http://www.castlecreations.com/tech-support.html |
02-22-2015, 11:47 AM | #8 (permalink) |
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Your metal insert for the owb may be slipping inside the aluminum housing. This has happened to numerous people, kde makes a nice upgrade, I have them on both of my 700's. ....
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Trex 700L Dominator X 2, Trex 450L Dominator X 2 |
02-22-2015, 11:58 AM | #9 (permalink) |
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Join Date: Apr 2012
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There is also a small spacer in the OWB, if it's missing it could be why you have the up and down play.
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02-22-2015, 04:08 PM | #10 (permalink) |
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Join Date: Jun 2014
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Quote:
The gain (Medium 25) is a little high. I run 11 on my 700. Try lowering it to low(15) and check if that solves (ease) the problem. I don't think the problem is in the owb cause you'll have power loss in any head speed, if that was the case, with or without governor. It's easy to spot the owb, listen to the motor, when loaded and you lose headspeed the motor will go on as nothing happen. You also can activate the CC log and check it after flight. It might clear the picture. Hope that helps. |
02-22-2015, 05:33 PM | #11 (permalink) |
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Join Date: Jan 2010
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I agree: #1 item to check is the gov gain. I use the "gov high" with no problems, but if the gain is too high, you will get chriping.
Here is the interesting part: The cheap, POS VBar clone (KBar?) may be overly sensitive or the cyclic gain may be set too high. Having the gain set too high on the ECS will start the governor oscillating which will cause a vibration (you may hear the OWB chirping). This governor induced vibration will start the POS VBar clone into its own cyclic oscillation. While you may not be able to afford a decent FBL, you can try turning down the governor's gain to see if that helps. |
02-23-2015, 03:57 AM | #12 (permalink) |
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Thread Starter
Join Date: Jul 2014
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Thank you guys for all your input. Here's what I've done so far. I took out owb and cleaned it and relubed it. Based on further inspection I noticed that the screws holding the main gear are held down only with loctite and the spacer in the owb housing is missing. So I'm in the market for new owb. I would really like to go with kde one but I can't find it anywhere in EU. Only direct from KDE. But It's kinda expensive since for 65$ I only get the bearing housing and for 75$ I get oem owb from align. Next, I changed the esc gov. setting to fixed head speed and lowered gov. gain. to 15. And I'm pretty sure that Kbar is not the problem, because I had it on my 600 and had no problems. Hope I can make another test flight soon and see if the problem is still there.
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02-23-2015, 04:08 AM | #13 (permalink) | |
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Join Date: Mar 2011
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Quote:
No the Kbar may be a problem. I see a lot of Kbar too sensitive to the gains, both cyclic and tail. There is no way to fix the tail wag and cyclic wobble but copy that setup file to a genuine VBar and everything is fine. |
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02-24-2015, 12:32 PM | #14 (permalink) |
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Thread Starter
Join Date: Jul 2014
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Today weather cleared up a bit so I made a test flight. When I first pluged in the battery one of my cyclic sevos woudn't work. I made another attempt after checking the wireing. Second time everything worked. Wierd!? I was cautious with my flight. I only went trough flight modes and did few pitch pumps to check for problem. Everything seams fine now. Found these on cc site and set up everything as in chart except pwm witch I left at 12.
I don't know if the esc settings were off or owb needed servicing but I guess it's fine now. Just to be sure if someone of you guys have KDE owb to spare I would really like to buy one. I tryed all the "local" rc shops and non of them had one in stock. I tryed KDE direct but with shipping to Croatia it's 109$!!!! Once again I would really like to thank you all for helping me!!!! Last edited by mrrockwell; 02-24-2015 at 02:01 PM.. |
02-24-2015, 04:18 PM | #15 (permalink) |
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Join Date: Apr 2012
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Try emailing them sales@kdedirect.com
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02-24-2015, 04:20 PM | #16 (permalink) |
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Join Date: Apr 2012
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Or maybe try these?
http://www.kdedirect.com/pages/vendors#europe |
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