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Old Apr 04, 2011, 02:37 PM
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Joined Jan 2007
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Updete from 4#6 to v120d02

Hi,

I'm trying to set v120d02 and looking for suggestions.
Some time ago I got 4#6s, which I updated to v120d01 and was happy until I decided to update it to v120d02. What I did is following
1. added one more servo,
2. updated all the upper parts on the main shaft,
3. added new Rx/Ts set: RX2610V and WK2603 and
4. setted the electronic/mechanics. I hope that I did this properly (I'm not a beginner): all reactions to my commands are ok (when I hold the heli in my hand), the reaction of all the three gyros is also correct.
But I still can not get v120d02 flying.

The problem is that after taking off heli starts to rotate very fast along its vertical axes and I have no chance to stabilize it. The similar things was doing sometimes my old 4#3. The direct explanation is that the tail rotor does not have enough momentum to stabilize the heli. But the problem is that before taking off it is enough, and after taking off still stay up to 2 sec, or sometimes can start to rotate immediately. The question is why this happens.
I use CFK blades main as well as the tail ones (from chinesejade and wowhobby). I checked all the gears and teeth are OK. I tryed to change sensitivity of the ruder gyro... Nothing helps.

The only idea I get is that the CFK blades for v120d02 are significantly heavier that the plastic ones from V120d01. Correspondingly it should develop higher Torque. As a result v120d02 should require more effective tail (e.g. one with higher rpm, or larger blades). But v120d02 and V120d01 have the same tails. So what is wrong? Why my v120d02 rotates?

Thank you in advance,
David
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Old Apr 04, 2011, 04:48 PM
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Air Vaca's Avatar
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Did you accidentally invert the slider links on the tail?
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Old Apr 04, 2011, 05:05 PM
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reverse your tail and see if that corrects it
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Old Apr 04, 2011, 05:19 PM
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livonia bob's Avatar
United States, MI, Livonia
Joined Apr 2009
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Quote:
Originally Posted by davidmancho View Post
Hi,

I'm trying to set v120d02 and looking for suggestions.
Some time ago I got 4#6s, which I updated to v120d01 and was happy until I decided to update it to v120d02. What I did is following
1. added one more servo,
2. updated all the upper parts on the main shaft,
3. added new Rx/Ts set: RX2610V and WK2603 and
4. setted the electronic/mechanics. I hope that I did this properly (I'm not a beginner): all reactions to my commands are ok (when I hold the heli in my hand), the reaction of all the three gyros is also correct.
But I still can not get v120d02 flying.

The problem is that after taking off heli starts to rotate very fast along its vertical axes and I have no chance to stabilize it. The similar things was doing sometimes my old 4#3. The direct explanation is that the tail rotor does not have enough momentum to stabilize the heli. But the problem is that before taking off it is enough, and after taking off still stay up to 2 sec, or sometimes can start to rotate immediately. The question is why this happens.
I use CFK blades main as well as the tail ones (from chinesejade and wowhobby). I checked all the gears and teeth are OK. I tryed to change sensitivity of the ruder gyro... Nothing helps.

The only idea I get is that the CFK blades for v120d02 are significantly heavier that the plastic ones from V120d01. Correspondingly it should develop higher Torque. As a result v120d02 should require more effective tail (e.g. one with higher rpm, or larger blades). But v120d02 and V120d01 have the same tails. So what is wrong? Why my v120d02 rotates?

Thank you in advance,
David
If the tail seems to work OK if you hold it in your hand and twist the heli back and forth. Maybe you are running to much pitch on the main blades? Did you adjust the tail in rate mode first? It's going to need more starting off with pitch on the tail then when it was a FP heli..
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Old Apr 04, 2011, 05:28 PM
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Good idea, Thanks,

I will check...
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Old Apr 05, 2011, 03:17 AM
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I have cheked and the both, the slider links as well as pitch are OK. In the no gas position the main blades have ~0 pitch and during the take off I need 1/2 gas...

The only hope is that I have to fix the play of the teil steering (thanks to "RobsHangar"):
Walkera 4G6 pitchslider repair (get rid of the play) (1 min 45 sec)

I will report what comes out.
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Old Apr 05, 2011, 03:51 AM
I love HAM
Joined Nov 2005
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Hi David,

Did you stick the tail servo plug in the correct output of the RX?

Check here

Sandor
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Last edited by Schermvlieger; Apr 05, 2011 at 03:56 AM.
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Old Apr 05, 2011, 07:02 PM
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Joined Jan 2007
151 Posts
I fixed play of the teil steering and this helps a little bit: no I can fly up to 5 sec ad then heli starts ti spin - no chance to control. It is not a beginers mistake in controlling of the heli (I have flown FP and CP helis before) - the heli really starts to spin itself. This "phenomenon" I observed with my old 4#3 (with brushed motors) too.

&Schermvlieger
Thank you. yes before starting this discussion I checked everything. E.g. for cheking of the ruder you put finger on the ruder servo arm and rotate a little bit the heli: if gyro works properly, then you will fill the servo reaction in your finger directed towards the compensation of this spinning...

At this moment I have three possible explanations of this sdtrange spinning:
1. may be the servo sensitivity i set is wrong.
2. the CFK blades http://www.wowhobbies.com/hm-4g6-z-0...d02andn-1.aspx are not OK for v120d02;
3. ther is some defect in my new RX2610V
4. may be I'm doing something else wrong

Slowly I'm comming to the conclusion that Walkera was wrong choise for me...
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Old Apr 05, 2011, 07:32 PM
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livonia bob's Avatar
United States, MI, Livonia
Joined Apr 2009
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Quote:
Originally Posted by davidmancho View Post
I have cheked and the both, the slider links as well as pitch are OK. In the no gas position the main blades have ~0 pitch and during the take off I need 1/2 gas...

The only hope is that I have to fix the play of the teil steering (thanks to "RobsHangar"): http://www.youtube.com/watch?v=8NTDV...eature=related
I will report what comes out.

In no gas you mean the throttle is all the way down.. and you have 0 degrees pitch at this point?? how much pitch do you have when the throttle is all the way up to full gas??
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Old Apr 05, 2011, 08:45 PM
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never mind... I'm stupid
Carry on

Bill
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Old Apr 05, 2011, 09:02 PM
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United States, MI, Livonia
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Originally Posted by Air Vaca View Post
never mind... I'm stupid
Carry on

Bill

uh what gear wrong side tail???
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Old Apr 06, 2011, 04:38 AM
I love HAM
Joined Nov 2005
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Well the only other thing I can think of is a problem in the tail rotor drive train; did you check all the gears for problems like improper meshing, missing teeth and stripped D-holes?
Also also, to test if the tail rotor blades are not up to the task you can make them somewhat (3 or 4mm) wider using light tape. Never mind exact balancing for the test.
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Old Apr 06, 2011, 04:48 AM
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Joined Jan 2007
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Quote:
how much pitch do you have when the throttle is all the way up to full gas??"]how much pitch do you have when the throttle is all the way up to full gas??
No idea, but when it takes off I do not feel that something is wrong (according to the sound the rpm should be OK: i.e. it seems to be similar to one I had in v120d01).

Quote:
did you check all the gears for problems like improper meshing, missing teeth and stripped D-holes
Yes I did thie before bothering the forue with my questions.

Quote:
Also also, to test if the tail rotor blades are not up to the task you can make them somewhat (3 or 4mm) wider using light tape. Never mind exact balancing for the test.
exactly that is what I'm planning to do: first I will change the CFK ones t the original plastic ones,...
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Old Apr 06, 2011, 10:26 AM
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USA, CA, San Diego
Joined Oct 2007
762 Posts
Quote:
Originally Posted by davidmancho View Post
Hi,

I'm trying to set v120d02 and looking for suggestions.
Some time ago I got 4#6s, which I updated to v120d01 and was happy until I decided to update it to v120d02. What I did is following
1. added one more servo,
2. updated all the upper parts on the main shaft,
3. added new Rx/Ts set: RX2610V and WK2603 and
4. setted the electronic/mechanics. I hope that I did this properly (I'm not a beginner): all reactions to my commands are ok (when I hold the heli in my hand), the reaction of all the three gyros is also correct.
But I still can not get v120d02 flying.

The problem is that after taking off heli starts to rotate very fast along its vertical axes and I have no chance to stabilize it. The similar things was doing sometimes my old 4#3. The direct explanation is that the tail rotor does not have enough momentum to stabilize the heli. But the problem is that before taking off it is enough, and after taking off still stay up to 2 sec, or sometimes can start to rotate immediately. The question is why this happens.
I use CFK blades main as well as the tail ones (from chinesejade and wowhobby). I checked all the gears and teeth are OK. I tryed to change sensitivity of the ruder gyro... Nothing helps.

The only idea I get is that the CFK blades for v120d02 are significantly heavier that the plastic ones from V120d01. Correspondingly it should develop higher Torque. As a result v120d02 should require more effective tail (e.g. one with higher rpm, or larger blades). But v120d02 and V120d01 have the same tails. So what is wrong? Why my v120d02 rotates?

Thank you in advance,
David
I'm sure you did step # 7 right?

Step 7. Go into GYRHLD, GYROSENS and change INH to GYRO/AUX2

Set to 0: 50-100%, HH mode 78% is typically required but may be more or less.
Set to 1: 0-49% Rate mode.

0: - This is for HH Mode which is 50%-100%
1: - This is for Rate Mode which is 0%-49%

And also make sure the rate switch is in the up position.

Also make sure that the drive shaft hasn't rounded out the D sections in the gears, this is easy to miss.
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Last edited by chevell; Apr 06, 2011 at 10:36 AM.
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Old Apr 10, 2011, 08:13 AM
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Joined Jan 2007
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Dear Fiends,

Thank you for your comments and sorry for late responce.
No I tried all and it does not work.

@chevell
I have 2603 (not 2801), and I went thrue the set up check list few times.
Pitch anngles are set to 75%, the gears are OK, all the reactions (including rudder gyro) are also OK, I used different gyro settings at Tx, but the heli still spinns.

I conclude that the thrust of the tail blades is not enough:
after taking off I manage to fly 1-5 sec. (usually keeping the rudder at maximum right), but then heli starts to spin left. When I keep it in hands I feel that already at 1/2 gas it has a small torque to the left, although I trimmed the rudder to the maximum right.

The only thisg is left is the blades: I use the CFK ones. There wheight = 8.8 gr, lengths = 13.8 cm; for the original v120d01 blades i find 5.2 gr and 12.0 cm. This means that for the same rpm the CFK blades will have almost two times higher angular momentum (~Mass*length^2) than the v120d01 blades. In reality this difference will be highe because the CFK blades are thiker and resulting in higher friction with air... Then v120d01 and v120 have the same tail parts, same gear.

So what is compansating the increased torque of the main blades after updating *d01 to *d02? How it worked out in your case? was a simple rudder trimming enough?

David
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Last edited by davidmancho; Apr 11, 2011 at 03:20 AM.
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