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Old Aug 14, 2011, 10:09 PM
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nav, you can turn the pot down on the rx! Do it in small increments because a little does a lot
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Old Aug 15, 2011, 12:46 PM
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Hi Mitchie, thanks for the advice. I just don't want to make anything worse by screwing around with the Rx. Although I realize I can mark the stock position on the Rx, and return to the stock value if things go wrong, it's still a concern I have. But is looks like I'm going to have to monkey with the Rx at some point.
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Old Aug 15, 2011, 10:32 PM
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You can mark the pots, but usually, you just have to move a very little bit to make a world of difference. If it gets worse, you have to go the other way
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Old Aug 16, 2011, 04:23 PM
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Just dont turn down the balance delay lol. Unless your ready.

I had to return the go pro. I couldnt live with the barrel distortion . It was worse inside. I may use my web cam for now .



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Originally Posted by Mitchie View Post
You can mark the pots, but usually, you just have to move a very little bit to make a world of difference. If it gets worse, you have to go the other way
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Old Aug 16, 2011, 04:44 PM
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Speaking of adjusting potentiometers, I've been doing that on the v400 to try to work out the wobble based on kdeans recommendation. The good news is that the wobble almost completely went away, the bad news is that for that to happen I had to turn the aileron and elevator gyro pots almost all the way down, and now it's very hard to control without the gyros....

This does lead me in the right direction and I know to look more into what is causing the gyros to go so crazy. I may try to mount the rx better. Also, i noticed that between the two main parts of the frame (the top part that holds the motor and main shaft, and the bottom part that holds the rx, battery, and esc) they can be rocked back and forth what seems like too easily to me. All of the screws seem tight, so I think it's just the weakness in the plastic parts and the metal part they are screwed into. I might try to strengthen that, but other than that I don't have too many ideas aside from start messing with stuff until i find something else that helps.

I took some pictures and videos of my rx and of how the heli flies before and after the gyro gain adjustment. Any further ideas on how I can get rid of the wobble, but still have some gyro sensitivity are welcome I had it flying fine before with the rx setup in the stock position. Had one crash that created a little wobble, and after my last crash the frame was bent and cracked. I since replaced and straigtend the frame and replaced the main gear, main shaft, and rewired it for better wire routing.

Below are pictures of my rx in the stock position (never had changed it) and my rx after I adjusted it and got rid of the wobble. I also have two videos of the bad wobble before adjusting it, and virtually no wobble after adjusting it. I still can't really fly it like that though, because I don't trust myself that much without more help from the gyros.

Wobble, before aile and elev gyro gain adjustment:
V400d02 wobble before gyro gain adjustment (0 min 22 sec)


After gyro gain adjustment to almost all the way down:
V400d02 after gyro gain adjustment (0 min 47 sec)



I want to go work on it now but unfortunately my microwave broke so that gets bumped to a higher priority I think it's just one of the door switches, but it might take a while to get to and test. Once that's done i'm back to the helis though
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Old Aug 16, 2011, 04:51 PM
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Originally Posted by Heli Biggie View Post
Just dont turn down the balance delay lol. Unless your ready.

I had to return the go pro. I couldnt live with the barrel distortion . It was worse inside. I may use my web cam for now .
oh, one thing I should add to my previous post, I tried turning the balance delay up (because that helped tame out my 450) but it didn't seem to help with this wobble I have.
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Old Aug 16, 2011, 04:56 PM
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Dilberto, have you been able to fly the heli with the wobble? After putting on my brushless, I had a wobble that seemed to go away as the battery got just a bit lower. Have you taken off the blades and then spooled the heli in your hand to feel for the wobble up close?
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Old Aug 16, 2011, 04:57 PM
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Say, how's you pinion/main gear mesh? Having the mesh too tight definitely made wobbling an issue for me.
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Old Aug 16, 2011, 05:14 PM
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Say, how's you pinion/main gear mesh? Having the mesh too tight definitely made wobbling an issue for me.
hmmm, i'll check the mesh because I did change out the main gear and a few other things without ever needing to unscrew the main motor. It had seemed ok, but not sure how well I checked it so it's worth another look.

I hadn't been able to fly it unless I turned down the gyros almost all of the way. I had tried a number of other things, like adjusting my throttle and pitch curves up and down, and I tried a few different types of batteries that I have, but always the same.

Taking off the blades I was able to spool it up fast and it seemed to do fine. Also I tilted the heli while it was spinning and the servos and gyros seemed ok.

I'm not sure if you can see it in that video, but after a number of take offs trying to work out the wobble, I noticed that as I start to lift off, as long as one part of the skids is still touching the ground, it doesn't wobble. Only when the bottom half is totally free from the ground it starts to wobble. This is kinda what made me wonder if there is too much side to side wiggle between the top half of the frame that holds the shaft and blades, and the bottom half that holds the battery and skids. Without having another v400 though I have nothing to judge it by. Basically if i have the heli sitting on the bench, and then move the frame that holds the main shaft, it will pivot back and forth a few millimeters.

Also i was wondering if anybody has heard of bad bearings causing that bad of a wobble. I didn't end up changing out the bearings because they seemed ok to me, but other than that I'm not sure what's left.
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Old Aug 16, 2011, 05:32 PM
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I don't know about the bearings, but when I was running the Alpha 400 motor and the 3.17mm pinion gear, I had side-to-side wobble issues. That extra 0.17mm of free-play between the pinion gear and the 3.0mm motor shaft caused the pinion to have a "closest approach" to the main gear. I found that the wobble improved if I made sure the mesh wasn't too tight at closest approach. I realize many here think I'm out of my mind for worrying about the 0.17mm, but I found it to be an issue. My worries were even more well confirmed when I found zero wobble issues with the Esky motor and the correctly fitted pinion from RTF-Heli. Now, I'm running the stock motor and there are no side-to-side wobbles.
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Old Aug 16, 2011, 06:00 PM
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You have your blades really loose. Once i get a perfect blade spot , i keep them tight now .and i snug them up every 2 batteries
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Old Aug 16, 2011, 06:11 PM
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Originally Posted by dilberto View Post
hmmm, i'll check the mesh because I did change out the main gear and a few other things without ever needing to unscrew the main motor. It had seemed ok, but not sure how well I checked it so it's worth another look.

I hadn't been able to fly it unless I turned down the gyros almost all of the way. I had tried a number of other things, like adjusting my throttle and pitch curves up and down, and I tried a few different types of batteries that I have, but always the same.

Taking off the blades I was able to spool it up fast and it seemed to do fine. Also I tilted the heli while it was spinning and the servos and gyros seemed ok.

I'm not sure if you can see it in that video, but after a number of take offs trying to work out the wobble, I noticed that as I start to lift off, as long as one part of the skids is still touching the ground, it doesn't wobble. Only when the bottom half is totally free from the ground it starts to wobble. This is kinda what made me wonder if there is too much side to side wiggle between the top half of the frame that holds the shaft and blades, and the bottom half that holds the battery and skids. Without having another v400 though I have nothing to judge it by. Basically if i have the heli sitting on the bench, and then move the frame that holds the main shaft, it will pivot back and forth a few millimeters.

Also i was wondering if anybody has heard of bad bearings causing that bad of a wobble. I didn't end up changing out the bearings because they seemed ok to me, but other than that I'm not sure what's left.
dilberto, You probably know why I'm saying this if you remember my vibration problem. I had changed everthing that could cause a vibration. While sitting still, the servos looked like they worked fine. Then when I go to lift off the vibration started. I think if you disconnect the links to swash plate. Then wiggle the wires on the servos as your working them, maybe something will show up. Also, with the power off, move the servo horn through the stroke and make sure its smooth all the way through.
What servos are you using? Anyway, good luck I hope you get it back in the air soon.
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Old Aug 16, 2011, 07:56 PM
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Originally Posted by Heli Biggie View Post
You have your blades really loose. Once i get a perfect blade spot , i keep them tight now .and i snug them up every 2 batteries
haha, i was wondering if anybody would notice that I usually keep the blades tighter, but loosening them was one of the things that I read about and tried to see if it helped (fyi, didn't help...)

barnstorm, i do remember your vibration issues. Because of that I had also thought maybe the servos, but they feel fine. They are metal gear and seem fine, but they are the cheap exi213 servos. Wasn't that the same that you had?? Mine have been through a lot, and even through that last crash on my 450. I had borrowed them while the 400 was under repair for the new 450, which in the end ended in an unexplained crash.... hmmm, maybe we're onto something here What I don't get though, if it's the servo why would it seem to work fine when I turn the gyro gains down I do have 3 new exi servos that were meant for the 450. Don't feel like modding them to fit the 400 if it's not going to help, but I could give it a shot. If it is the servos I might opt for some better ones for the 450 anyway.

Thanks for the ideas. I'm still working on the microwave but I think I figured out the problem. One of the three (yeah, three) door switches inside the microwave that have to be closed in sequence is not giving the correct resistance reading on the multimeter, so i'm going to order a new part online. By the way guys, once you get good at repairing your helicopter, most other consumer electronics and home appliances will seem simple in comparison Just for poo and grins, I attached a picture of my microwave being taken apart
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Old Aug 16, 2011, 08:56 PM
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Thanks for the ideas. I'm still working on the microwave but I think I figured out the problem. One of the three (yeah, three) door switches inside the microwave that have to be closed in sequence is not giving the correct resistance reading on the multimeter..
Mine came with a circuit diagram inside. However it has been 23 years and that piece of paper probably has faded away already.

If I remember correctly, it has 3 switches as well. One to tell the controller, another to connect power and the last one is to short circuit the input to the magnetron directly if the other 2 switches do not do their job. It is better to blow the fuse than keeping the magnetron running when the door is open.

I probably would let it go instead of fixing it if it fails. My wife wants a new one years ago for colour match, but it is spacious and I hate the turntable in the newer ones. The passive deflector fan of the original design does a good job in steering the microwave. Anyway if it works why bother.

BTW, have you checked the two plastic pieces between the upper and lower frames of the V400?

Mine hit a resonance issue at one time. Anything that changes the resonant frequency may help. I believe I added cable ties around them to make the RX work. Try giving the RX additional cushion, like a gel pad.
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Old Aug 16, 2011, 09:17 PM
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[QUOTE=dilberto;19063968] I had borrowed them while the 400 was under repair for the new 450, which in the end ended in an unexplained crash.... hmmm, maybe we're onto something here.

My Blueray crashed because the elev servo burned out. The sticker on the servo said Exceed but it was the same as the EXI213. On the bench the servo worked but when you pushed it through the stroke it jammed. I replaced those with HS65 ?? Hitec and there was no more problem.
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