V-Bar Tail Tuning and Troubleshooting Guide with Mikado Logo Example

[ElectricSheep]

Originally Posted by OverTemp

Man it was a pain to get the glue off the shelf and vBar.

Glad to hear you're all fixed up now!

Re: the glue...
This is minor in the whole scheme of things, but I hated having to scrub off the leftover glue and servo tape/foam bits off the sensor tray and sensor...

So now I lay down a piece of clear packing tape that fits on the sensor shelf, and I also put another square piece of the same type of tape on the bottom of the VBar sensor. Then I put the gyro tape on the sensor (the packing tape is now between the gyro tape and the sensor), then mount the sensor in the tray. The packing tape is more than sticky enough for the sensor and gyro tray. I'm 100% positive the sensor isn't going anywhere.

If/when I have to take the sensor out, I just peel the packing tape off the sensor tray and everything comes off the heli in one pull. Peel the packing tape off the sensor and throw the 2 pieces of packing tape and gyro tape in the trash. You never even have to touch the gyro tape. Both the sensor and tray will be 100% clean -- no scraping necessary. Hope that helps!

[alexf1852]

Originally Posted by ElectricSheep

Glad to hear you're all fixed up now!

Re: the glue...
This is minor in the whole scheme of things, but I hated having to scrub off the leftover glue and servo tape/foam bits off the sensor tray and sensor...

So now I lay down a piece of clear packing tape that fits on the sensor shelf, and I also put another square piece of the same type of tape on the bottom of the VBar sensor. Then I put the gyro tape on the sensor (the packing tape is now between the gyro tape and the sensor), then mount the sensor in the tray. The packing tape is more than sticky enough for the sensor and gyro tray. I'm 100% positive the sensor isn't going anywhere.

If/when I have to take the sensor out, I just peel the packing tape off the sensor tray and everything comes off the heli in one pull. Peel the packing tape off the sensor and throw the 2 pieces of packing tape and gyro tape in the trash. You never even have to touch the gyro tape. Both the sensor and tray will be 100% clean -- no scraping necessary. Hope that helps!

So the gyro tape is strong enough to stick to the smooth side of the packing tape? I'll have to try this.

[crash1000]

whats the best solution to get a perfect tail in heavy sudden pitch changes like very hard and fast hard tictocs or moving the heli by max pitch when its taildown like a tail 90 degree down rainbow? (tail is exaclty 90 degree down and just uing max pitch going from one side of the field to another)

having a higher I-gain and lowering the precompensation?
or
higer precomp and lowering the igain?

both will give the same result I think, but wich one is the better solution that wont effect other moves?

[terrabit]

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[Justin Pucci]

Originally Posted by crash1000

whats the best solution to get a perfect tail in heavy sudden pitch changes like very hard and fast hard tictocs or moving the heli by max pitch when its taildown like a tail 90 degree down rainbow? (tail is exaclty 90 degree down and just uing max pitch going from one side of the field to another)

having a higher I-gain and lowering the precompensation?
or
higer precomp and lowering the igain?

both will give the same result I think, but wich one is the better solution that wont effect other moves?

Crash,

Wow! Sorry for the really late reply on this one...it's been a busy last few weeks.

Increasing I-gain will always result in the tail holding better under hard and sudden load changes. As you mention above, you will need to lower the precomp though. Give that a try and report back if you haven't already fixed the problem long before my reply...

[Wogboy]

When you say precomp, are you talking collective or cyclic, or both?

[MrMel]

Both, cyclic usually is best with 50% of that of collective, or slightly lower

[Justin Pucci]

Originally Posted by MrMel

Both, cyclic usually is best with 50% of that of collective, or slightly lower

The Master got to it before I could! Thanks, Frederik!

[Wogboy]

Ok thanks guys. I'll see how it goes.

[terrabit]

Hi guys!

Okay, I dropped collective precomp by two points, cyclic precomp by one point and raised I-gain by ten points. The tail feels a little better but still juts with torque when pitch piumping, maybe two or three inches on my 700E. I'm just not sure how far I should go. I'm tempted to just call it good.

Also, you'll notice that the control loops are pretty far apart at 17 and 61. Should that be telling me something?

Thanks!

[Justin Pucci]

John,

See my PM, but you will likely need to drop your precomps lower than that... My general rule of thumb is to lower your collective and cyclic precomps by 3 and 2 points, respectively per 5 points of I-gain increase. This means that with stock settings, if you increase your I-gain to 70, then you ought to be running collective and cyclic precomps somewhere in the range of 16 and 5, respectively.

Please keep in mind that this is simply a guideline that I've found to work in most cases. You will need to fine-tune once you get in the ballpark and as you well know, not all birds are the same.

Good luck!

Cheers,
-->J

[terrabit]

Check and check! Thanks!

[OverTemp]

Try 75 on the I gain. I was getting kicking with the lower I gain value. Tweaked into it's happy place at 75.

[terrabit]

Any input on wildly uneven control loops, like 16 and 71?

[MrMel]

Originally Posted by terrabit

Any input on wildly uneven control loops, like 16 and 71?

It's normal, in one direction, the heli has very easy to stop (torque from main rotor helps), the other direction it's fighting against the torque to stop.

[terrabit]

Thank you Mr Mel, I am very happy to hear your input on this.

[carlocivicsi]

I'm going to be purchasing a mini vbar for my new 600e pro but i have some newbie questions.

how do i control the gyro gain with the radio? i have a dx8
and how do i know when I'm in a rate or heading hold? with align a light would turn red for rate and green for heading hold.

and since programming the vbar is all with the computer what would the settings with ccpm and pitch curves be with the dx8 when setting up a new heli?

thanks.

[MrMel]

Vbar is always in HH unless you program it specially not to be in the VBar program.
You will (in express) be setup Gain via radio as part of the setup process.

the DX8 should be setup as 1 servo (no mixing), pitch curves should be as you need them, but 0-100 for programming purposes.

[vad0r]

Hi , thanks for this very usefull topic

I am flying a logo 600 and have a "fast wagg" on the tail when doing rainbows,hurricanes and fast translations. I have reduced the "main" gain of the tail gyro in my DX8 to get 80-85% but i doesn't change anything.

I have inspected the mechanical setup and found no problem at all (the heli is stock, never crashed).

I'm using JIVE 80HV and MKS BLS980 tail servo.

I'm running "stock" setup in the VBAR menu :



Here is a video where I can hear my problem



I Will try to reduce the "P gain" to 70 and see what happenned.

If you have any other suggestions...

[Justin Pucci]

Vad0r,

While I'm not able to see your tail wag on the video (it's actually pretty tough to capture), I can definitely hear it getting really angry when you load things up. That having been said, it appears to be holding quite well, so I'd bet you've just got an over-gain situation on your hands...

I would suggest setting your P and I gains to between 70/70 and 75/75, dropping your precomps to around 10-15 for collective and 3-5 for cyclic, and then retune the tail to your liking. Remember to tune the common gain in a funnel or hurricane...keep increasing it until it buzzes or wags (over-gain), then decrease it by a few points, recheck and you should be fine.

Nice flying and good luck!

Cheers,
-->J