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600 Class Nitro Helicopters 600 Class Nitro Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


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Old 07-25-2013, 11:05 AM   #1
chavanel
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Default TREX 600n DFC issues

Hi freaks

I've been reading a while about issues I'm finding during my new TREX 600n DFC build. I apologize as some of the issues have already been present, and are documented in other threads, but I wanted to document all my findings in one post, so here I am.

1. First of all, when leveling my swash at mid-stick, I found my servos twitching and jumping and acting really crazy and weird. First I thought my 3GX was faulty, so I changed with another unit that was flying no issues. Same behaviour. I moved my SATs (DSMX) away from the front of the heli (where electronics for Align 2-1 regulator are). The problem was still there, not as noticeable and frequent as before, but there indeed.

So this is something related to interferences (even switched off my Wireless router I have nearby), never found something similar in my other builds. First guess, the Aling 2-1 regulator, it's the only component I'm not used to, never used that before. So I plugged an old CC BEC just to confirm if the problem disappeared, and it disappeared completely!

As I haven't found anyone else having the same issue, my first question would be... is this normal? Do I have a faulty 2-1 unit? Servos? I'm thinking of getting a CCBEC Pro or even HV servos to avoid this situation, however before I do that, I wanted to hear opinions from you guys.


2. I cannot make swash maintain level at high and low stick. I know I'm not the only one. Mid-stick, perfectly leveled, high and low, 1 or 2 servos are a little off. I read this should not be a concern as long as at mid-stick all is leveled, however I'm a perfectionist I checked my other helis and I didn't find any where swash keeps level all its travel though the shaft (I didn't check this before). Those other helis flight great, so I think I will let this one go off my mind.


3. Main shaft Still shocked to realize that Align really placed the wrong shaft in my brand new kit, and I do have to pay for that error. Anyhow, I will get the new and appropriate shaft, problem solved.


4. I found about the shaft being shorter when I put the head on with blades to measure 0° at mid stick. I found then that my swash wasn't at the middle of the shaft available space. Giving full positive collective, servos bind and swashplate reach it's maximun possible travel. Also, at mid-stick I got like 1.5° with ball links fully fastened (no room to fasten them more). Servos are centered, 90'ed, linkages are as per manual (31.5mm or so), and swash is leveled at mid-stick.

I cannot take the swash further down adjusting linkage length, as elevator servo/link marks the limit.

I read others have this problem, but I haven't found a documented solution from anyone. Some say I could take elevator servo down a bit (moving the arm or subtrimming) and then adjust linkage from other servos to lower the swash and level it. However, elevator servo won't be centered and I don't like that.

My questions are: 1) do the new main shaft for this kit correct this problem? Is it longer also in the top or something like that? 2) Is this another design problem from Aling? 3) Am I doing something wrong? Is anybody else owner of a 600n DFC kit having this issue? What did you do about it?

I wanted to take this bird to fly this weekend, however due to these issues, I don't see how

Sorry for the lenght of my post, hopefully someone could share some experiencies around these issues.

Happy flying!
Oscar
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Old 07-25-2013, 08:56 PM   #2
garvin74
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Default Main Shaft

I believe using the correct shaft does solve this issue. I don't have a DFC kit, but my nitro pro was converted to DFC. At first I had to make my own shaft, then they came out with the first shaft which was too short, and then I finally got the correct shaft. If this is a design flaw in that kit, I would think that the three arms that go from the bell cranks to the swash are simply to long and you can purchase shorter ones to correct this problem, even tho you shouldn't have too. As for the 2 n 1, I believe it is set for 5.1 to 5.8 volts somewhere around there. So I don't think switching to HV servos would make a difference. I would recommend a CC BEC Pro which is what I was using at 6.0, but now im on LIFE packs with no BEC/VR. And I would go with either a switchglo pro or pushglo, your preference. I have a switchglo on my NX4 and a pushglo on my 600. Hope this helps.
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Old 07-25-2013, 09:01 PM   #3
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I haven't experienced any of that. Mine went together great with no issues other than the stock clutch liner being too thin.
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Old 07-25-2013, 09:06 PM   #4
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Also, as far as the main shaft is concerned, I put many flights on the shaft that came with the kit with no problems-it just wouldn't reach the lower bearing block. I now have the newer, longer shaft and the only difference is the length on the bottom-approximately ten millimeters. I can tell you that the shorter shaft has no impact on swash centering.
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Old 07-25-2013, 09:38 PM   #5
chavanel
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Originally Posted by williey78 View Post
Also, as far as the main shaft is concerned, I put many flights on the shaft that came with the kit with no problems-it just wouldn't reach the lower bearing block. I now have the newer, longer shaft and the only difference is the length on the bottom-approximately ten millimeters. I can tell you that the shorter shaft has no impact on swash centering.
Sorry, you got the new DFC kit with the stock main shaft, and you are saying that your swash centered great and you didn't have any issues getting 0º at mid-stick?

That's interesting, what am I doing wrong? I have exactly the same kit and I can assure you (and I'm not the only one) my swash is not at the middle of the main shaft available travel space (is higher) and I can't get 0º at mid stick with servos centered. Did you do anything different?

Thanks for all replies.
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Old 07-26-2013, 07:23 AM   #6
williey78
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I believe what I had to do was turn the ball links on the elevator one turn so that the elevator arm is just slightly lower than level. So that would mean you would turn the top link out one turn and the bottom link in one turn to bring it down a hair. I know that you mentioned that you are meticulous about having everything 100% level and I am as well. However in this case, setting the elevator arm slightly lower is the only way to get the swash centered and will NOT affect flight performance once so ever. Everything else will be perpendicular and 90 degree angles as it should. After you do that, level your pitch and aileron links with the elevator arm and install the head. I have my links about one or two turns out on the blade grip arms to get zero pitch. If you have your settings correct in your tx, you should get equal travel in your swash. If not, you might have to go back and play with the elevator arm again but it should not be far off. It takes a little time to get it right but you just have to keep tinkering with the swash position and the blade grip arms but I promise you it will achieve zero pitch and equal movements with the swash. Please understand that if you are slightly low on your elevator arm, it will not hurt a thing and you will never notice it in flight.
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Old 07-26-2013, 11:09 AM   #7
chavanel
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Originally Posted by williey78 View Post
I believe what I had to do was turn the ball links on the elevator one turn so that the elevator arm is just slightly lower than level. So that would mean you would turn the top link out one turn and the bottom link in one turn to bring it down a hair. I know that you mentioned that you are meticulous about having everything 100% level and I am as well. However in this case, setting the elevator arm slightly lower is the only way to get the swash centered and will NOT affect flight performance once so ever. Everything else will be perpendicular and 90 degree angles as it should. After you do that, level your pitch and aileron links with the elevator arm and install the head. I have my links about one or two turns out on the blade grip arms to get zero pitch. If you have your settings correct in your tx, you should get equal travel in your swash. If not, you might have to go back and play with the elevator arm again but it should not be far off. It takes a little time to get it right but you just have to keep tinkering with the swash position and the blade grip arms but I promise you it will achieve zero pitch and equal movements with the swash. Please understand that if you are slightly low on your elevator arm, it will not hurt a thing and you will never notice it in flight.
williey78:

Thanks a lot for your comments. What you say makes total sense, and I will try that this evening and see how it goes.

I would really like to know what ALIGN position on this is

Thanks again, man.
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Old 07-26-2013, 12:55 PM   #8
mdz12345
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I built my Trex 600N DFC back in April and experienced many of the troubles you noted. I inferred from your post that the servo twitch you are experiencing is fairly constant. If this is the case, you may want to contact Align for assistance. The servo twitch I experienced was very random. It would twitch a few times, clear for several minutes, and then twitch again. This is a known issue and does not affect flight performance (as long as it is only doing it in DIR mode). I was able to resolve this issue by upgrading the 3GX to version 3.1. Once upgraded, the only time I noticed this servo twitching was when I had the USB dongle attached and it was much less prevalent. Additionally, 3.1 significantly improves take-off and landing stability (Do a search on “3GX tip over on take-off”).
I was able to rectify the issue with the swash not being at 0 degrees mid-stick by filing the base of the elevator ball link which allows it to sit a little lower in the elevator arm. The shaft length doesn’t impact the position of the swash in any manner. I contacted the store (Align Trex Store) where I bought my kit and they sent me a new main shaft free of charge.
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Old 07-26-2013, 06:51 PM   #9
chavanel
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Quote:
Originally Posted by mdz12345 View Post
I built my Trex 600N DFC back in April and experienced many of the troubles you noted. I inferred from your post that the servo twitch you are experiencing is fairly constant. If this is the case, you may want to contact Align for assistance. The servo twitch I experienced was very random. It would twitch a few times, clear for several minutes, and then twitch again. This is a known issue and does not affect flight performance (as long as it is only doing it in DIR mode). I was able to resolve this issue by upgrading the 3GX to version 3.1. Once upgraded, the only time I noticed this servo twitching was when I had the USB dongle attached and it was much less prevalent. Additionally, 3.1 significantly improves take-off and landing stability (Do a search on “3GX tip over on take-off”).
I was able to rectify the issue with the swash not being at 0 degrees mid-stick by filing the base of the elevator ball link which allows it to sit a little lower in the elevator arm. The shaft length doesn’t impact the position of the swash in any manner. I contacted the store (Align Trex Store) where I bought my kit and they sent me a new main shaft free of charge.
Hi mdz12345

My twitching is random, similar to your case, but always reproducible. Not present in normal mode, only in DIR mode. You say it was corrected upgrading to 3.1, my 3gx is already on 3.1. I'll try upgrading again with the same FW and see if it's still there. However, its better to know it's something known and does not affect the heli in flight.

Thank for your help, really.
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Old 07-27-2013, 08:16 AM   #10
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I have never had mine twitch. I am running the stock Align servos and 3gx 3.1. I have had a couple of defective servos out of the box but no twitching. Could you post a video of it?
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Old 07-27-2013, 02:22 PM   #11
chavanel
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Quote:
Originally Posted by williey78 View Post
I have never had mine twitch. I am running the stock Align servos and 3gx 3.1. I have had a couple of defective servos out of the box but no twitching. Could you post a video of it?
Will try later and post the video.

Thanks!
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Old 07-28-2013, 09:37 PM   #12
chavanel
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Ok, so I followed all recommended approach to solve my elevator link level and 0º pitch at mid stick. I had to turn two complete turns servo linkages for elevator, but finally got there (0º at mid stick and full collective travel, no binding.

Just wanted to thank all people who shared their thoughts. I maiden my bird today, and it was awesome. Servo twitching didn't cause a problem during flight (as you said), and the stock (shorter) main shaft didn't cause any issues either.

Again, thank you so much.

Happy flying!
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Old 07-29-2013, 05:44 PM   #13
williey78
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Glad you got it worked out!
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Old 08-02-2013, 11:05 AM   #14
HedgeHeli
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Yeah I had a few issues, although the only build issue was with the ball link on the tail (flip flop attached to the frame at the back) needing to be mounted opposite to the manual otherwise the carbon rod was bent like a banana.

- The clutch liner needed replacing flight one, got a Lynx heavy duty one now and that's better but I think Align have made the clutch itself too stiff.
- One cyclic servo was twitching out of the box, this is in flight not on the desk like others have seen - I ignore that one
- Tail servo went after about 15 flights
- COG WAYYY out cant believe using the kit Align recommend you need to add so much weight to the front to get the COG
- The fuel pipe walling is too thin to cut off the flow using the supplied fuel pipe clips so flooded my heli bag
- Poor build quality on the new torque tube black gear off the tail block it was buckled
- Stripped the button screw on the head - annoying and never done it before, think the metal is poor quality.

Personally:- Can't see the canopy very well in poor light, looks great on the floor though

Everything is fixed now and I am having a great time with it, but this being my 6th heli (Blade 400, Raptor 50, HK 450, Align 600n, Align 700e V2 and this Align600n DFC) its the worst out of the box experience I've had. It's the 3rd Align I've built and def the worst, I do think their QC has slipped.

Still not 100% sure about DFC either, I think the new HFC head from Goblin is the way forward. DFC just seems too stiff to me and all the servos are taking all the strain, we will see.
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