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4G3 Walkera 4G3 Helicopter Support


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Old 07-17-2009, 06:09 AM   #1
oldhui
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Default 4G3 initial setup

After watching those exciting videos on the Internet, I finally bought a 4G3 double-brushless. I'm quite a newbie in the subject except from flying co-axial micro infrared heli.

When I tried to take off, the 4G3 just isn't as stable as I thought. It slides to the left (which I believe is normal) and then tends to drift in other directions. The heli is only 1 inch from the floor. Counter-acting seems to be extremely difficult and it also has a tendency to turn anti-clockwise. I can do reasonably well in he simulator and I wonder if this is my problem or the heli's.

I tried to hold it in hand and trim it so that it feels stable. But some time it tends to turn anti-clockwise.

So far I have broke 2 sets of blade, 1 swash-plate, and the tail fin. :-( The experience is quite frustrating as I spend more time repairing instead of flying.

I check and see that the blade tracking is off. Is there any other things that I need to tune before it can hover (until I get a new set of blades)? What about the CG? Is it going to have an effect on the stability? Is my gyro setting too low?

Any help is appreciated.
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Old 07-18-2009, 05:44 AM   #2
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Assuming no,problems at the tail e.g. the tail rotor shaft is perfectly straight, tail gears meshed not too loose and not too tight, sounds like you might have too much pitch on the main blades creating more torque than the tail can handle. Spin up again in your hand to full throttle/full pitch and note how much the blades slow down by when you do. Then switch on dip 11, rotate V1 fully anti-clockwise and you should see the head speed up with the throttle at mid-stick.Then up the throttle to max and adjust knob V2 so that there is slightly less pitch on the blades than before - i.e. head should not slow down by as much as it did. You can test fly it with the dip switch on, if the heli doesn't lift off then turn V2 clockwise, if it spins turn V2 anti-clockwise - eventually you should find the perfect position for V2, switch dip 11 back off, job done

You're description of it flying after coming from a co-ax sounds normal, these helis are not easy to fly and take a lot of practice, training gear I'm sure would help. Stick with it though as once you do get the hang of a single rotor heli your co-ax will become an ornament

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Old 07-18-2009, 03:46 PM   #3
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To make the blades last a lot longer I fasten mine together and grind them both simultaneously to maintain symetry. Grinding the ends so that the carbon fiber strips sticks out the farthest allows the CF to take the brunt of the impact. Seal the ends of the blades with some CA glue.
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Old 07-20-2009, 06:25 PM   #4
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Thanks for the help.

Now I am quite sure that the tail rotor is not generating enough torque to counteract the main rotor.

I tried the method you described and it is still trying to turn anti-clockwise when the throttle is up. When I have enough pitch to lift it off, it starts to turn CCW. I also tried increasing the rudder mix in the receiver. The tail rotor spins faster but it is still not enough to hold the tail.

I don't know if the tail motor is bad. It is the Walkera double-brushless set up. Once a crash knocked the the tail motor out of place and it stuck. Luckily I pushed outter part back in and it rotates again. When I hold heli in my hand and swing the tail left and right, I can feel the tail rotor rotating slower or faster. Seems that the gyro is working and the tail motor does try to spin up/down to keep the tail.

I don't know what else can be wrong. The heli is new and I never got it hovering. :-(
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Old 07-21-2009, 02:57 AM   #5
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Possibly something not quite right with the tail set up.
Check for a bent shaft by looking at the tracking of the tail rotor as it spins.
Also gears could be meshed too tightly or not tightly enough - it's quite a finicky tail to get right.
When you blow on the tail rotor it should spin very freely - if it doesn't, may give you an idea as to what might be wrong.

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Old 07-21-2009, 11:16 AM   #6
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There is no gear at the tail as it is a BL. I briefly checked and the shaft is ok. No problem with tail rotor tracking. I blow it hard and it does rotates.

I'll check out stuff tonight (connection, other physical damage, etc.). If nothing works then I may consider changing to a 2.9g BL tail motor (in Chinese Jade? Mine is head-heavy anyway). It is frustrating that even the stock BL motors couldn't get it lift off.

Does anyone know if the stock Walkera tail ESC works with the 2.9g BL?

Thanks.
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Old 07-21-2009, 12:36 PM   #7
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Quote:
Originally Posted by oldhui View Post
There is no gear at the tail as it is a BL.
Ah sorry, yes you did mention that in your first post, in which case please ignore what I said regarding the tail motor, gears and shaft.

I wouldn't rush out and buy a new motor unless the one you have has suffered damage. The 2.9 motor is a bit more powerful but plenty other folk fly with the motor you have so finding the problem should be the priority - and there's no guarantee the 2.9 motor will be powerful enough to overcome whatever problem you have

Did you notice much change in headspeed when you turned V1 anti-clockwise?
Also, has the heli always been like this?

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Old 07-21-2009, 09:09 PM   #8
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The head speed does change when I have DIP 11 on and turning V2. It all behaves correctly: more V2 -> more pitch -> slower head speed. When V2/pitch is enough for it to lift off, the CCW turn kicks in. I couldn't fix it no matter how much rudder mix I put in (by turning the dial on the RX).

As far as I can remember it has been like this from the beginning. I once broke the swash plate and change it. I don't think this is related.
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Old 08-11-2009, 05:06 AM   #9
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Ok. I am still struggling with my 4G3.

Changed to Chinese Jade 2.9g brushless motor with original Walkera tail ESC and still no use. Then changed to Chinese Jade's ESC and still the same. Tried pitch settings, etc. When there is enough lift to take off, it starts to spin anti-clockwise.

What can be wrong? Could it be messed up settings? I followed Walkera's default settings in the manual and other suggested settings on the net. Still no use. Increase rudder mix (even to the max) in the receiver. Still the same.

Seems that I am rebuilding this whole thing from parts. It has a RX2605a receiver. All servos work fine and the gyro seems working (tail rotor changes speed when I move heli CW/CCW). The brushless main motor is working.

The only thing that it doesn't do is to hold its tail.
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Old 08-11-2009, 06:19 AM   #10
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Quote:
Originally Posted by oldhui View Post
Tried pitch settings, etc.
Can you explain what you did?

I still think it's likely you have too much pitch / not enough headspeed.
When you adjust V2 with dip 11 on, turn V2 down so that the heli won't take off even at full throttle, then start turning it up click by click until the heli just takes off at full throttle - does it still spin?

Also, is blade pitch 0 degrees at mid-stick ok?
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Old 08-11-2009, 08:13 PM   #11
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Quote:
Originally Posted by Dusty1000 View Post
Can you explain what you did?

I still think it's likely you have too much pitch / not enough headspeed.
When you adjust V2 with dip 11 on, turn V2 down so that the heli won't take off even at full throttle, then start turning it up click by click until the heli just takes off at full throttle - does it still spin?

Also, is blade pitch 0 degrees at mid-stick ok?
Dusty,

I set dip 10 and dip 12 according to Walkera's recommendation.

For dip 11, I first turned both V1 and V2 fully anti-clockwise. Then apply throttle and slowly turn up V2. When it gradually "wants" to hover, it starts to spin anti-clockwise (slowly, as it is still in contact with the ground). So, either it doesn't lift off. When it starts to lift off, it spins anti-clockwise.

If I add enough V2 and throttle so that it lifts off (1 feet off the ground). It spins CCW like a top. This is weird as I suppose the gyro will exercise the tail rotor to counter act the spin.

Maybe I should check all connector and wires for contact/physical damage. Other than that I have no clue. Seems that the RX is the only possible cause. What about the TX?
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Old 08-11-2009, 10:57 PM   #12
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Quote:
Originally Posted by oldhui View Post
For dip 11, I first turned both V1 and V2 fully anti-clockwise. Then apply throttle and slowly turn up V2. When it gradually "wants" to hover, it starts to spin anti-clockwise (slowly, as it is still in contact with the ground). So, either it doesn't lift off. When it starts to lift off, it spins anti-clockwise.
1) Did you apply full throttle when you did this?

2) is blade pitch 0 degrees at mid-stick ok?

I assume you have wired the tail motor correctly and it blows air to the right when looking at the heli from the rear? Also check the tail rotor isn't slipping on the shaft

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Old 08-12-2009, 06:08 AM   #13
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Quote:
Originally Posted by Dusty1000 View Post
1) Did you apply full throttle when you did this?

2) is blade pitch 0 degrees at mid-stick ok?

I assume you have wired the tail motor correctly and it blows air to the right when looking at the heli from the rear? Also check the tail rotor isn't slipping on the shaft

Dusty
Dusty,

Thanks for the patience and persistent help.

Yes. I turned DIP 11 on, turned both V1 & V2 fully anti-clockwise, apply full throttle (no lift off, of course), then slowly turn up V2. It gradually wants to take off and starts to have the tendency to spin anti-clockwise. Fully trim right rudder helps a bit but still not holding tail. If I turn V2 further, it tries to lift off but spins like a top. V1 is kept fully anti-clockwise throughout the whole process.

Mid-stick pitch is roughly 0% (checked with eyes only). That's why it won't lift off at mid-stick, isn't it? But I can't understand why it starts to spin CCW as soon as there is enough lift for take off. I did all these in "normal mode" (not 3D) of course.

Also, even before it can lift off, I can hear the tail motor "pulsing". i.e. speeding up and down. It looks like a gyro sensitivity problem but adjusting the gyro sensitivity (via DIP 12, V1) doesn't help. I expect to see the tail "wag" if the gyro is over/under-sensitive but at least there should be enough anti-torque from the tail rotor to allow it to lift off??

Yes. Tail motor is wired correctly. It blows to the right. The tail holds on low throttle but not with higher throttle.

Different rudder mix tried. I can see the different tail motor speed but still max rudder mix doesn't hold the tail. Tail rotor is firmly pushed into the shaft. No slippage. And I have tried the spare rotor blade as well.
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Old 08-12-2009, 08:41 AM   #14
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Quote:
Originally Posted by oldhui View Post
Dusty,

Thanks for the patience and persistent help.

No probs, now I've started....

Sounds like you're doing everything correctly regarding pitch set-up anyway.
How did you connect the power wires for the tail esc? If you're using a splitter cable, perhaps one of the connections on it is dodgy.

I have my tail esc (chinese flea, same as yours I think) power wires soldered onto the terminals for the wires going to the battery on the main esc.

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Old 08-13-2009, 08:57 PM   #15
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Dusty,

I am using a Y-splitter. I tested it with an ohm-meter and it seems alright.

Maybe I can try soldering the tail ESC's power to the main ESC's. The main ESC is shrink-wrapped so I'll need to cut the wrap open before I can solder.

I'm wondering if this is a mechanical or electronic problem. Tried some lubricant on the main shaft bearings today. Check main shaft and it looks ok. The bearings actually turn quite smoothly. Unplugged and re-plugged connectors to RX and still no use.

I supposed the tail-holding is done on the heli, not the transmitter. So what left behind are the RX, brushless main and ESC. The servos should play no part in this.

BTW, turning the rudder stick does increase/decrease tail rotor corectly. It is just not holding tail.
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Old 08-14-2009, 06:35 PM   #16
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Dusty,

Soldering the tail ESC power to the main ESC doesn't help. Still the same problem. I even tried the 2-battery configuration (with a common ground). No difference.
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Old 08-14-2009, 07:06 PM   #17
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To check that the blades rotate freely enough, tighten them up, and with your fingers on the blade holders, flick them round as fast as you can, they should rotate 2 to 3 complete revolutions after you release your fingers - if they don't it's a sign that something is binding, or gear mesh too tight etc.

Apart from that i can't think of anything else to suggest, trying a new 4 in 1 would at least let you know if that is the problem, not the sort of thing you'd want to buy until you're sure it is though

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Old 08-28-2009, 07:37 PM   #18
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Hey guys,

I'm pretty new to this myself. I just ordered a 4g3 looking for something small I could fly in the house when I can't fly outside. I'm pretty new to this, only had a blade 400 for about a month or two, and no I can't really fly it...yet....

I've been reading the forums alot, and there is one thing I noticed hadn't been checked, but if the gyro has a reverse switch did that get changed? Since your heli is only rotating in one direction, and no matter how much trim you apply, it sounds like the gyro is trying to hold the tail but it's only adding to the problem.

Not sure if that will help.

oh and check out this thread for a few other things people have tried.

http://www.helifreak.com/showthread.php?t=144479
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Old 08-29-2009, 01:58 AM   #19
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Hi and welcome to the forum, thanks for the suggestion, but the gyro in these helis is part of the 4 in 1 and can't be reversed, and the tail motor in this case is brushless which is set up is totally different to the brushed tail motor in the thread you linked to.

You'll love the 4G3 once you learn to fly, but it's not easy as you've probably gathered, it takes practice and lots of it. Do you have a sim? If not good idea to get one, we all buy them eventually so may as well get one now and practice on it - Phoenix is what I would recommend. I'd also get the Blade fixed as it's a LOT easier to fly than the 4G3 due to it's size and weight.

Best of luck and let us know how it goes

Dusty
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Old 08-29-2009, 02:07 AM   #20
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Well, when you get it figured out let us know what you did.

Nothings really wrong with the Blade 400, just don't have a lot of room to fly it as much as I'd like to...I only have a few parking lots that when they are full their kinda small... ohwell...

I decided to get a small Collective Pitch heli that I could fly inside. I realize the smaller the heli the harder it is to control, but hopefully it will make my 400 a lot easier to fly.
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