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4G6 / V120 Series Walkera 4G6 / V120 Series Helicopter Support |
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11-01-2011, 04:21 PM | #1 (permalink) |
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Join Date: Dec 2010
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Save me from "myself" please!
I wouldn't normally be asking this question but since I recently screwed up the pitch and tracking on a B450, I thought I'd better check with you guys. Specific to an M120D01 and if I want to "reduce" pitch on one blade, it would appear that I need to "lengthen" the link on the high blade...............not shorten it? Would that be correct?
If so, is it best to just pop the link end off the ball with fingernail or unscrew the entire ball from the headpiece and turn the link that way? I have one blade that's just very slightly out of track under power and I dunno whether to just leave it alone or "strive for perfection". From historical perspective, I figure I have about a 50/50 chance of making things worse when I try to make things perfect. One more question. I've weighed both tail rotor blades and one comes in at .365 gr and the other at .368 gr. Is this close enough for this bird? Have also noticed that as compared with a 4G6, the tail rotor blades on the M120 must be slightly longer cuz it's a helluva lot easier to just "nick" the tail rotor blades on the M120 as compared the 4G6. I never nicked the blades on the 4G6 but have done it 3 times now on the 120. To date, the damage has been very, very minor and easily repaired with a piece of "fine" emery cloth. |
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11-01-2011, 07:50 PM | #2 (permalink) | |||
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Join Date: Nov 2008
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Quote:
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If the tracking is ever so slightly off, do not bother with it as it may be impossible to totally correct tracking. By adjusting the link (you can only adjust by a full turn) you may throw the tracking off the opposite way. Quote:
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Some people have a problem for every solution... |
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11-01-2011, 08:00 PM | #3 (permalink) |
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Thread Starter
Join Date: Dec 2010
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Thanks John! Appreciate your typical "reasoned" replies to all questions!
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11-02-2011, 11:42 AM | #4 (permalink) |
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Join Date: Jun 2011
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you should pop of the link, I do not advise unscrewing the link ball. They should actually have lock tight on them. I think that it is actually good practice to make sure that the grip metal ball end extension is tight, as well as the matching ones on the swashplate. They will give excessive play if even a slight amount loose. i usually remove the whole link, removing it from the plastic uper swash links as well. I have a little tool I use to pry them off, but the fingernail method works well. I measure them first so I have a reference. They are difficult to get perfect. Also make sure that the swash is level, and the balance off when adjusting the blades. The thing is that the blades can appear to be farther off than they are, but the swash can induce a phantom effect at times when the fbl is doing something weird. I have had issues with bad servos ect that caused some strange interactions with the swash plate and rx. Now I make sure that I have the swash level and then take out the battery or put in adjustment mode.
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11-02-2011, 11:48 AM | #5 (permalink) |
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Join Date: Jun 2011
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As far as the tail blades go, the rx does not like vibes, and if you can balance them out then I would. The best ting for this is the extreme blade balancer with the smallest attachment they make. It suspends the scale with magnets and so is able to pick up even minute differences in weight. I wouldnt loose sleep, but the more vibes you remove the better it will run! Also, I have found that the m120d01 simulated carbon blades do in fact easily hit the ground. They are the largest tail blades walkera makes for the 120 cp tails. There are 4g6 ones that are shorter, but are not as good. The best solution for this is to use skid nuts on your landing gear. The ones for the trex 250 will work, or I get a foot or so of appropriate sized nitro fuel line and it makes dozens of skid nuts. I have notices that the m120d01 has the least clearance stock with the tail blades. Once you get a little more clearance you should be fine. Emory cloth, fine file or sandpaper is fine as long as you do the same thing to both tail blades.
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11-02-2011, 02:13 PM | #6 (permalink) | |
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Join Date: Dec 2010
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Quote:
Just found an older post by Vronny indicating that all I have to do is remove the two screws under the boom and loosen the servo holder. Assume I also remove the boom supports? Then gently pool on the boom, slide it out far enough to remove / replace new gear, slide everything back in and reinsert and tighten screws. Does that sound about right? Vronny, I know you have an M120D01 with the "215" motor as well. This motor seems to have enough speed and torque to wipe out the gears in a heartbeat. All I did was brush the carpeting with the main blades and that was all it took to "peen" off a tooth or two from the front bevel. Gentle blade strikes with the 4G6 and an HP08 weren't enough to routinely strip bevel gears. Last edited by Mikey2; 11-02-2011 at 03:28 PM.. |
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11-02-2011, 07:53 PM | #7 (permalink) | |
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Join Date: May 2010
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11-03-2011, 02:07 AM | #9 (permalink) | |
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Join Date: Dec 2010
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11-03-2011, 04:40 PM | #10 (permalink) |
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Join Date: Dec 2010
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Well, you guys were correct. That was "easy" as compared with performing the same task in a 4G6 and even "that" wasn't too bad. This was indeed a snap. The front bevel was indeed crunched and it surely didn't take much t' do it.
It's flying again but again has the same sort of "jittery" in flight characteristics as it did when brand new. It sort of "quivers" in hover and it's always been a little more "sensitive" to vibration than the 4G6. I've looked everything over and I just don't see any more smoking guns. The gear train feels smooth and I certainly don't see anything else obvious. Main shaft seems straight and true as does tail shaft. Don't see any "wobble" in the main gear. What I've described "gradually" diminished with flight time when the heli was brand new so just wondering if things need to find their sweet spots again? The Rx is sitting on the usual thin piece of ESC mounting tape and the ESC is plastered directly beneath the Rx. The "cable" end is sort of shoved under one of the frame crossmembers and that's how it was delivered to me. With this motor, have noticed that the ESC gets "warm" (not hot) but it gets warm enough to cause the ESC tape on the "front" end of the ESC to lose bond strength and "droop" a little. Given that these things appear to be so damned sensitive to any kind of vibration, wondering if I should further separate the Rx and ESC and place the ESC on a "good" piece of 3M mounting tape? Any ideas or should I just give it some "time" again? The blade strike which ruined the front bevel in the first place was just a mere brush against the carpet and didn't even leave any marks on the blade tips. Hard to imagine there was any further subtle damage and I can neither feel nor see any other damage to the main gear. Guess I could try a new set of main rotor blades as well. What d'ya guys think? Oh, one more thing. Noticed (to my dismay) that when I removed the old bevel, I pulled the shaft out of the tail gear causing it to drop out of the tail drive unit. After a few minutes of fiddlin' around was able to reinsert w/o further ado but "that" was inconvenient! |
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