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4G6 / V120 Series Walkera 4G6 / V120 Series Helicopter Support


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Old 06-04-2012, 10:28 AM   #1
Smithye46
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Default Walkera v120d02s spinning on take off, help!

Hi everyone I'm new to the site and this is my first post, hopefully you can help. So basically I was just out flying and everything was going well until I did a tight turn and suddenly the chopper started to spin on its own so I cut power and put it into the grass! So when I went to take it up again it starts to spin without any input! Don't have a clue why?

Please please help, many thanks!
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Old 06-10-2012, 08:34 AM   #2
will792
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Quote:
Originally Posted by Smithye46 View Post
Hi everyone I'm new to the site and this is my first post, hopefully you can help. So basically I was just out flying and everything was going well until I did a tight turn and suddenly the chopper started to spin on its own so I cut power and put it into the grass! So when I went to take it up again it starts to spin without any input! Don't have a clue why?

Please please help, many thanks!
Verify that tail rotor is consistently spinning while you rotate main gear. Also when you add throttle you should see tail rotor spin. That is what is used by gyro to maintain helicopter stability. Also verify that you did not flip some switch on the transmitter (i.e. mix) to a mode that reduce gyro gain. Typically beginners fly with mx (top right side corner on Walkera TX) set to 0 and somewhere in the configuration gyro gain is set to ~80 for this switch position.

I would say since stability changed without you crashing your helicopter most likely you flipped some switch which basically disabled gyro.
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Old 06-11-2012, 02:14 PM   #3
Heli-opolis
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Check to see if you are able to hold the tail rotor while you try to spin the main rotor by hand.

If holding the tail rotor doesn't prevent the main rotor from turning, or vice versa, the problem is with one or more of the tail gears. The usual problem is that the 'D' hole in the gears that 'lock' them to the shaft so they don't rotate, except with the shaft, can get worn out to an 'O'.

Or, the gears on the shaft running along the tail boom can slip off the ends causing the same problem.

You might want to look into modifying your 02S with what is called the 'Slipper clutch' if stripped gears are your problem.
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Old 06-21-2012, 09:10 PM   #4
neoneo
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Quote:
Originally Posted by Smithye46 View Post
Hi everyone I'm new to the site and this is my first post, hopefully you can help. So basically I was just out flying and everything was going well until I did a tight turn and suddenly the chopper started to spin on its own so I cut power and put it into the grass! So when I went to take it up again it starts to spin without any input! Don't have a clue why?

Please please help, many thanks!
Quote:
Originally Posted by will792 View Post
Verify that tail rotor is consistently spinning while you rotate main gear. Also when you add throttle you should see tail rotor spin. That is what is used by gyro to maintain helicopter stability. Also verify that you did not flip some switch on the transmitter (i.e. mix) to a mode that reduce gyro gain. Typically beginners fly with mx (top right side corner on Walkera TX) set to 0 and somewhere in the configuration gyro gain is set to ~80 for this switch position.

I would say since stability changed without you crashing your helicopter most likely you flipped some switch which basically disabled gyro.
Quote:
Originally Posted by Heli-opolis View Post
Check to see if you are able to hold the tail rotor while you try to spin the main rotor by hand.

If holding the tail rotor doesn't prevent the main rotor from turning, or vice versa, the problem is with one or more of the tail gears. The usual problem is that the 'D' hole in the gears that 'lock' them to the shaft so they don't rotate, except with the shaft, can get worn out to an 'O'.

Or, the gears on the shaft running along the tail boom can slip off the ends causing the same problem.

You might want to look into modifying your 02S with what is called the 'Slipper clutch' if stripped gears are your problem.
I'm having this problem to. i only crashed 2 times. but they were hard. anyway, the main rotor spins without the tail rotor when given enough throttle to pull up. i checked out the link for the slipper clutch mod but i cannot even understand the first step. i hope to find a vid for that, but in the mean time, can anyone tell me how to get my bird back where it belongs. in the sky. FYI the canopy cracked just as easy as the mini cp canopy and the skids cracked faster lol
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Old 06-22-2012, 10:33 AM   #5
Heli-opolis
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The main thing is to figure out what is spinning that shouldn't.

There are a number of places gears can be loose:
  • The gear that meshes with the main gear.
  • The gear on the opposite end of the driving rudder shaft.
  • The gear in the rudder motor cage.
In addition to those, check for chipped teeth on all the gears involved as well.
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Old 06-22-2012, 12:49 PM   #6
ChitownMatt
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+1 to all

Tail Drive Gears

If you fly the 02s, you will get very familiar and quick at replacing these gears. Even with the slipper clutch, the gears need to be replaced periodically. Without it... even the most gentle brush of the tail rotor against the carpet (or anything else) will ruin one of the gears and induce the dreaded counter clockwise spin.

Slipper Clutch and servo saver mods are a must with the 02s.... Or just don't crash. lol.
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Old 06-22-2012, 09:03 PM   #7
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Quote:
Originally Posted by ChitownMatt View Post
+1 to all

Tail Drive Gears

If you fly the 02s, you will get very familiar and quick at replacing these gears. Even with the slipper clutch, the gears need to be replaced periodically. Without it... even the most gentle brush of the tail rotor against the carpet (or anything else) will ruin one of the gears and induce the dreaded counter clockwise spin.

Slipper Clutch and servo saver mods are a must with the 02s.... Or just don't crash. lol.
After owning and flying three different 4G6 modeIs (Walkeras of yesteryear) and remembering all of the weak gearing discussions we all had 3 years ago, I find these 02S "D" hole discussions t' be pretty funny cuz the joke's on us. Although I only replaced just two "B" gears in all the time I flew that model and with gearing known to be weak, here we are with the D02 "S" and it's obviously more chunky gears and now they strip from the inside out in an absolute heartbeat.

I used to be able to drag my 4G6 through the carpet with nary a hiccup but the 02S spins out a "D" hole if you look at it cross-eyed. As you suggest, "even the most gentle brush of the tail rotor against the carpet", is literally all it takes to wipe out at least one gear guaranteed if not everything but the main gear. I wonder what we've gained? The first time it happened, I thought it must have been a fluke. By the 3rd time, I knew it was just another case of more = less. I think we should quit sellin' our recycled milk jugs to Bejing cuz they're comin' back to us in Walkeras.

Bob Livonia's slipper clutch has proven t' be the only satisfactory solution.
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Old 06-24-2012, 08:20 AM   #8
shayaan
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Check for ball links on the rudder it cpuld be one of them popped loose check your switches on the tx and see what switch enables what
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Old 06-26-2012, 11:01 PM   #9
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I hate to disagree but I can rebind mine when it happens and it fixes it. Just saying it does happen, even if the heli is tottaly fine mechanicly. Did I mention walkera is a cheap heli!!!

Sorry but I've had it with mine... It's always something. If I could get a 1/4 of what I've put into it, I'd sell all walkera stuff.......

I gave em a shot, 3 times and have 1 bird that might lift off without spinning or it might spin out of control. Rebind and it's fine,. again...
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Old 07-06-2012, 02:18 PM   #10
Mikey2
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Quote:
Originally Posted by ChitownMatt View Post
+1 to all

Tail Drive Gears

If you fly the 02s, you will get very familiar and quick at replacing these gears. Even with the slipper clutch, the gears need to be replaced periodically. Without it... even the most gentle brush of the tail rotor against the carpet (or anything else) will ruin one of the gears and induce the dreaded counter clockwise spin.

Slipper Clutch and servo saver mods are a must with the 02s.... Or just don't crash. lol.

I'm sure that most of you guys have already checked out the "130X" part of the forum and found that E-Flite is encountering exactly the same TT / gear issues as we've experienced with Walkera stuff. Everybody's already talkin' about slipper clutches but lamenting the fact that the design doesn't seem to offer enough "room" for installation.

I'm sure somebody'll figure out something but I find it really interesting that Blade has certainly had time to research the issue and I know that HH tech support routinely contributes to the forum. God bless 'em for that but sounds like it's just another case of a new model introduced without being fully sorted. When it's so easy for the buying public to find weaknesses in a new design, makes ya wonder why a clean sheet of paper design would not address some of the TT / small gear issues more effectively.

With Bob's slipper clutch in my current D02S, sounds like the Walkera's currently far more rugged than the 130X in exactly the area where it counts. Time will tell!
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Old 07-07-2012, 06:50 AM   #11
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Since installing L-Bob's slipper clutch, I haven't wrecked a single front tail drive gear. That being said, the problem I have now is that if I crash, I sometimes dislodge the drive shaft from the D-hole of the rear gear! Then it spins out the inside of the D and I'm back where I started before the slipper clutch.
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Old 07-16-2012, 04:54 PM   #12
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Apparently that's what I'm having now. Tried lifting off yesterday, spin spin spin then it broke a servo with the insides hanging out. I almost think I should just buy another and use this one for parts, then I think I should just sale it so I can get my trex 250 finally. I know, that has problems too, but I bet they aren't as often. But it would be cheaper to get another d02s and use the one i have for parts. Just wondering if it is worth the money.
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Old 07-21-2012, 10:19 PM   #13
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Quote:
Originally Posted by gabeoravitz View Post
Since installing L-Bob's slipper clutch, I haven't wrecked a single front tail drive gear. That being said, the problem I have now is that if I crash, I sometimes dislodge the drive shaft from the D-hole of the rear gear! Then it spins out the inside of the D and I'm back where I started before the slipper clutch.
Replace the "B" gear and CA it on the shaft.. making sure that you have the boom inserted all the way in the tail holder and the frame and locked down.. Also back off the slipper clutch adjustment a hair if you flying style allows it..
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Old 07-22-2012, 09:13 AM   #14
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If you think about it, if something interferes with the driveline, the rotational energy has to go somewhere-- this is true with any brand heli that has a non motor driven tail. You'll either strip the gear cogs-- if you make those stronger, you'll strip the D-holes, if you make that stronger you'll strip the main gear, if you make that stronger you'll shred the torque tube... if you somehow make that indesctructable, then the heli will chicken dance on the ground and you'll tear the whole thing up.

I like having the tail gears being the weak link. Minimizes the damage, cheap and easy to replace. Plus the slipper clutch makes changing the gears a rare event anyway.

Just remember that this issue is inherent to any shaft driven driveline (including the larger t rex models). You can change to a belt driven model (which basically has a "built in" slipper clutch), but then you'll trade one set of maintenance issues for another. Or switch to a motor driven tail and live with crappy performance.

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Old 07-22-2012, 10:58 AM   #15
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Quote:
Originally Posted by gabeoravitz View Post
Since installing L-Bob's slipper clutch, I haven't wrecked a single front tail drive gear. That being said, the problem I have now is that if I crash, I sometimes dislodge the drive shaft from the D-hole of the rear gear! Then it spins out the inside of the D and I'm back where I started before the slipper clutch.
Make absolutely sure your boom is not cracked.
The same thing was happening to me when my boom had a crack and it would flex a bit and pull the a or b gear off the shaft. It did't look broken, but if you can hear tiny noises when twisting it, it's time to replace it.
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Old 07-22-2012, 06:32 PM   #16
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A walkera fanboy I am not, but mine has been pretty trouble free. I put the "spins" on it after crashing into a lawnchair and came to find out that the only trouble on the bird (besides the cracked canopy) was that the tail linkage had popped loose and mysteriously disappeared. My motor losened up from the main gear on another crash in my front yard, and just today I put it in a small bush growing against the brick on my house, after it nearly gave me a haircut and I lost sight of it.

I'm starting to have a hard time understanding what all the hu-bub is about. That said, walkera is a little cheap and I had a tx loose signal when I touched it while checking out the bird for the first time.

Check your linkages, check your gears, check your switches. Rebind if that doesn't help. Check the tail servo and make sure it is working properly. Make sure that it sets up at 90deg and that your tailfins appear flat from above when the servo is at 90. She's a pretty crash resistant little heli, already saved me about 200 bucks in B4503D damage.
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