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Old Sep 15, 2012, 01:24 AM
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Adjusting V911 Trim

Hi.
Am new to this site, so please excuse me if asking in wrong place.
Just got into the RC Helicopters..... had Sigma 107 as my 1st one.
The V911 is my 2nd Helicopter.
Have seen great reviews on it.
But I am leary (spelling?) of it because it appears so fragile, and initial start-up steps have been troublesome.
Installing the battery into the unit seems to be very hard and pushing it into the holder requires enough force that I fear breaking something especially if I should slip. I also was quite concerned about the wire that hangs out from just below the battery area. I thought initially that it was a loose wire, but later concluded that it was the antenna. Only saw it on 1 picture of a helicopter from online site.
But anyway, my question is: how do I adjust the trims? The instruction manual that came with it is very unclear and poor english, and never even explains what the 'crab' trim is, so would appreciate if someone could give me a overall breakdown. Initial start-up of my helicopter has it falling/leaning to the left when first starts off.
Thanks for any help for this newb.
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Old Sep 15, 2012, 01:54 AM
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v911 is indestructable. The parts look flimsy, but they're so light weight they don't get any damage during a crash. The canopy, which takes the brunt of crashes is a hard shell and doesn't tear.

As for the flight characteristics. It has a strong tendency to pendulum, so that's what you'll find yourself fighting at first. Find a large windless area, lift the heli up three feet, and let it swing back and forth (don't touch the cyclic) until it settles into a shallow circle.

It will have a tendency to turn left or right, use the trim below the left stick until it stops turning. You will continue to have to adjust this as the battery drains and the propeller loses power.

Then pay attention to how the heli hovers, even tho it's moving in a shallow circle (a.k.a. Toilet bowl effect), it will have a bias and start to drift in a certain direction, use the trims around the right stick to counter it.

When you turn off the transmitter, the trims on the left stick reset, only the trims on the right stick are saved.

As for the heli 'tilting' left on liftoff. That's normal. Has to do with gyroscopic forces around the main and tail rotors. You'll have to learn to give the heli a quick push forward and right to counter it. You'll also notice the heli tilted right while hovering, that's normal.


The v911 is meant for leisure flying. Not precision. Great for learning orientation, throttle management and helicopter flight characteristics, but not so good when you want fine control. You need to push the sticks on the v911 quite a bit to be able to make it to move, if you do the same thing on a 6ch, you'll flip the heli.
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Last edited by Hajile; Sep 15, 2012 at 02:03 AM.
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Old Sep 15, 2012, 06:56 AM
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I would plus one what the previous post said i would also mechanicly trim it out and fine tune with the transmitter. Just google mechanicly trimming the v911 and all will be good. also have fun its an awesome little heli i am taking mine wind surfing in an hour.
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Old Sep 15, 2012, 01:30 PM
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Thanks for the response Hajile, but what is the 'cyclic'? Also what is what the manual calls the 'Crab' trim?
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Old Sep 15, 2012, 02:14 PM
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I don't know what 'crab trim' is either. When you find yourself needing to constantly push the stick to center it, the trim lets you digitally move the center point to where the center of the joystick is. That's all trim is.

Elevator is what points the nose of the heli up and down, it's tied to the up and down motion of your right stick.

Aeleron makes the heli lean left and right, it's tied to the left and right motion of your right stick.

Those two combined is called a cyclic. So when someone mentions cyclic, they're referring to the right joystick of your controller. It's also the term used for the large joystick real pilots uses to control their helicopters.

EDIT: Finally found the manual. It's a translation error. Crabbing is what you call a sideways motion. They used that word instead of aeleron trims.
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Last edited by Hajile; Sep 15, 2012 at 09:58 PM.
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Old Sep 17, 2012, 02:50 PM
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Thanks Hajile, have done a little 'flying' time, but still do not feel that I know how to adjust the trims. Should I adjust the Alleron(Crab) when the heli drifts left while flying? If so, do I just move the trim slider right? If I have the left control held in the same spot and the heli drifts up or down, should I be adjusting the left side Speed trim? I tried a few Crab adjustments while flying and really could not see the difference.
Also, pushing the top left button on the transmitter does not seem to cause any difference on the display - always shows Mode 1. How do I get to Mode 2? Am confused..... is this button for a speed change option, or is it for for Rudder Conversion (as manual shows - what does it exactly convert in the Rudder???) or is it for something else???
Thanks for the help.
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Old Sep 17, 2012, 03:18 PM
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Guys:

Mode 1 is always shown on the display - ignore it. The tx is always in mode 2. The top left button switches between low and high rates.

Cyclic controls are those that control swashplate movement and depending on operating mode, may be on different sticks. On mode 2, such as most v911's, it is on the right stick.

Crab movement comes from the tendancy of an actual crab to move sideways. And some do refer to aileron trimming as crab adjustment. Same thing just expressed differently.

Trim your heli manually, by adjusting servo arm lengths. Start with digital trims centered. Observe the swash movement and adjust the arm length to make it stop drifting. The digital trims are best used for fine tuning only.

Daryoon's blog here has a very concise procedure.

regards . . . g
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Old Sep 17, 2012, 04:56 PM
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Wow, did not know what I was getting into......... too much info for me at this stage of commitment, I guess.
I do not even know how to take my small heli apart, and do not WANT to do that at this time...... just want to be able to control it.
Gordonzo - thx for your feedback, but your answer to my what does the top left button on my transmitter do ..... left me with more questions. What does changing the 'rate' do? ... and why does the manual say the button is for 'Rudder Conversion'?
Still need info on adjusting trim with the sliders.
Thx.
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Old Sep 17, 2012, 05:47 PM
Different fly 4 different guy
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Quote:
Originally Posted by Bob6831 View Post
Wow, did not know what I was getting into......... too much info for me at this stage of commitment, I guess.
I do not even know how to take my small heli apart, and do not WANT to do that at this time...... just want to be able to control it.
Gordonzo - thx for your feedback, but your answer to my what does the top left button on my transmitter do ..... left me with more questions. What does changing the 'rate' do? ... and why does the manual say the button is for 'Rudder Conversion'?
Still need info on adjusting trim with the sliders.
Thx.
OK 'Rudder Conversion' is a bad translation or something . . . . Basically low rates are about 60% of cyclic movement and high rates 100% (rudder is also affected).

Hover the heli in front of you, nose pointing away from you. Give it some gentle cycle stick in any direction. Now press the top left button once and try it again. The difference will be very obvious. You can also watch the little bars on the cyclic display; 3 for low rates, 4 for high rates.

No need to disassemble anything for mechanical trim. Just pop off the servo link from the ball on the swashplate and turn to shorten/lengthen the link as needed.

You might as well start to learn now - if you are going to fly you are going to have an 'unscheduled landing' sooner than later. Repair is easy once you get started. Don't fret about any of this, just fly and have fun. Cut the throttle on imminent crash to avoid (or at leasr minimize) damage.

regards . . . g
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Old Sep 17, 2012, 06:39 PM
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Originally Posted by gordonzo View Post
OK 'Rudder Conversion' is a bad translation or something . . . . Basically low rates are about 60% of cyclic movement and high rates 100% (rudder is also affected).

Hover the heli in front of you, nose pointing away from you. Give it some gentle cycle stick in any direction. Now press the top left button once and try it again. The difference will be very obvious. You can also watch the little bars on the cyclic display; 3 for low rates, 4 for high rates.

No need to disassemble anything for mechanical trim. Just pop off the servo link from the ball on the swashplate and turn to shorten/lengthen the link as needed.

You might as well start to learn now - if you are going to fly you are going to have an 'unscheduled landing' sooner than later. Repair is easy once you get started. Don't fret about any of this, just fly and have fun. Cut the throttle on imminent crash to avoid (or at leasr minimize) damage.

regards . . . g

Enjoying and learning from this thread as I am in the same position, although I have already lengthened the aileron rod a couple of turns. Have not been able to Houver yet, to much wind and no room in the house.
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Old Sep 17, 2012, 08:28 PM
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The easiest way to see what the button does is to take it outside. While going full forward, press the silver button and you'll notice that it leans a bit more forward, and consequently, faster. Especially useful when you're flying against wind.

You don't have to trim your helicopter perfectly, that's really not possible in any heli. I've often found myself clicking back and forth on my GeniusCP because 'perfect tail hold' is between two trims, and that changes depending on the battery. If the heli is unbalanced enough that you notice it, then you can use the trim. Otherwise you can just leave it. The rudder trim is the one that you'll be adjusting the most. After flying the heli for a while, that's when you'll be proficient enough to notice the bias and compensate with the trims accordingy.

No need to drown yourself in info. Just relax and fly. You'll learn things as you go, and the heli will be able to survive it.
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Old Sep 24, 2012, 01:46 AM
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Well, have flown it enough now to be dangerous. On my last outing one of the magnets in the balance bar fell out, have new one on order ($2.04). Need info on putting new one on. I know there is a screw holding it on. Do I just pop the 2 linkage connections off/on ? Afraid to do repairs on it without explicit instructions because is so delicate.
Note that I also broke a landing skid leg. Think the glue job I did should work, as looks like replacing the skid requires replacing the battery holder as well.... and would require soldering the 2 wires to the main board. Correct?
Last question, to take the canopy off, do you just pop (pull) the plastic off the cross bars?
Thx.
P.S. One of the problems I have flying is that the heli seems to turn so quick when move rudder control, and also, when is any distance from me, can't tell whether is front of back of heli I see so don't know whether s/b forward or reverse to get back to me.
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Old Sep 24, 2012, 04:57 AM
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Originally Posted by Bob6831 View Post
Well, have flown it enough now to be dangerous. On my last outing one of the magnets in the balance bar fell out, have new one on order ($2.04). Need info on putting new one on. I know there is a screw holding it on. Do I just pop the 2 linkage connections off/on ? Afraid to do repairs on it without explicit instructions because is so delicate.
Nothing to it really, pop the two linkages, remove the screw, and then replace it. It's a very simple construction. The only complicated flybars are on the big ones. Thank goodness flybars are going out the door.

Quote:
Note that I also broke a landing skid leg. Think the glue job I did should work, as looks like replacing the skid requires replacing the battery holder as well.... and would require soldering the 2 wires to the main board. Correct?
Yes, they soldered everything to the board to save on cost. You need thicker wires and connectors to make everything pluggable.

Quote:
Last question, to take the canopy off, do you just pop (pull) the plastic off the cross bars?
Yes. You can try squeezing the top and bottom a bit to widen it and make it easier to put back.

Quote:
P.S. One of the problems I have flying is that the heli seems to turn so quick when move rudder control, and also, when is any distance from me, can't tell whether is front of back of heli I see so don't know whether s/b forward or reverse to get back to me.
It's a rather long explanation and has something to do with cheap patentiometers and deadzones. But suffice to say that i believe you're realizing the benefit of being able to set exponentials on a programmable TX. Consider it part of your learning. For a basic v911 transmitter, all i can say is that you'll learn to get used to it with practice.

Regarding orientation, that's also part of your practice. That's why you have people here talking about canopy colors so they can see which way it's facing.
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Old Sep 24, 2012, 11:17 AM
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Thanks for the quick reply Hajile.
I read somewhere that when connecting the charger to a USB port, you should plug in the USB first and then put the batteries in, otherwise could ruin the charger. Is this so?
And if so, does this mean that I should remove the batteries from the charger first before I disconnect from the USB port?
Thx.
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Old Oct 05, 2012, 04:39 PM
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V911 - Learning

Hi.
Have made some good progress on flying my V911. Have also just got a E-Sky Simulator... but not sure that it really helps me.
The most problem I have with flying is ....as heli gets farther from me and I have to do something to bring it back, I find that it is very difficult to know whether it is facing me or is just the opposite.
I also have a broken leg on the landing skid, and I tried both super glue and hot gun glue to repair it........ but neither seems to hold up to a hard landing. Any suggestions?
Thx.
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