RunRyder - how much gain is too much?

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Beginners Corner > how much gain is too much?

nmrs
Senior Heliman
Location: Austin, TX

I don't think I am moving it, though when plugging the battery in (deans connectors) I might shift it a little, but I try and be really careful doing it. I see this drift on every flight though, and I always try to carefully plug it in while not moving it.

05-29-2008 04:50 PM

Altrex
Senior Heliman
Location: West Bend, WI

possibility

something i had seen in the past was if you fly with a weak battery pack, the tail seems mushy. I found this out when I put in a brand new pack and my motor was running much faster. Originaly, I did not get any wag, but with the new battery, had to dial down my gain.

05-29-2008 04:53 PM

HeliSmith
Senior Heliman
Location: Canyon Country, CA

As we learned from Finless Bob optimal servo horn position for the 450 is closest to the servo yoke.

Now that you are on the gear switch plug in trying not to move the heli. Then click the gear switch 3 times down up down up down up. This will reset the gyro. Then try again and if it still drifts try to rebind the thing one more time.

P.S. Yeah rudder trim doesn't work with HH mode.

Edit:
Good point on the low battery and low headspeed could be a problem too!

*** Team HeliHobby.com ***

05-29-2008 04:53 PM

HOMEPAGE

Funky Trex
Key Veteran
Location: Westerville, OH - USA

How/where is your gyro mounted?

Do you have any gyro wires running near the motor or ESC?

05-29-2008 04:53 PM

nmrs
Senior Heliman
Location: Austin, TX

I doubt it's the batteries. I'm seeing this with the align 20C battery that came with the heli as well as both of my Kong Power 25C batts.

I will try the flip the switch 3 times trick before taking off to make sure I didn't accidentally shift it when plugging in battery, and if that doesn't work, will try rebinding.

Gyro is mounted under the boom at the back of the heli body (as in the finless videos -- this makes it difficult to see when the light goes solid, so rather than lying on the ground, I generally just wait 10 - 15 secs before spinning up the head after powering it on). Just looking at it now, I see that I did mount the gyro slightly off center. When looking at the nose of the heli, the gyro is flush on the right side of the gyro mount pad, and hanging off on the left about 3mm or so). Will that affect anything? I have more gyro tape. Should I remove it and reattach it more centered?

No gyro wires are anywhere near the motor or esc. Well before I say that, how near is near? ESC is mounted up front under batt tray. Gyro wires (they are really long with the voltage step down in there) are bundled up under the main gear, about 4mm behind the main shaft, strapped with a cable tie to the bottom of the heli.

In the first pic, you can see that the gyro is slightly offcenter, shifted a little to the right in that view. The second picture shows where my excess gyro wire is bundled.

05-29-2008 05:56 PM

Zaneman007
Key Veteran
Location: Texas - USA

I hate to ask but: "do you have the gain from the gyro plugged into the correct channel and the correct polarity (i.e. the gain wire is going to the servo input line and not the ground or negative wire).

I just helped someone with the same problem that you are describing, except it was a JR gyro. One sub-trim click would produce a slow clockwise rotation and a click the other way would produce a slow counter-clockwise rotation. The problem was the gain was to low.

If you can run the gain up to 105% with no hunting, something ain't quite right.
My suggestions would be;(and these are from experience)
1) make sure the gain lead coming off of the gyro is plugged in correctly, securely and in the correct direction.
2) increase the mechanical gain on the servo.
3) hold the tail while you make tail inputs (make sure the servo is in good working order)
4) make sure the belt is not slipping.

After that, I'm clean out of ideas.

I'd rather be flying

05-29-2008 06:16 PM

nmrs
Senior Heliman
Location: Austin, TX

Quote
1) make sure the gain lead coming off of the gyro is plugged in correctly, securely and in the correct direction.

I think it is plugged in correctly. When looking at my AR6200 with the bottom (side with the pins) facing me, the wire is plugged into the farthest pin away from me. If it was plugged in incorrectly I don't think I would be able to switch between HH and rate mode, which I currently can. When I toggle the gear switch into rate mode, the HH led on the gyro goes out.

Quote
2) increase the mechanical gain on the servo.

I have no idea how to do this.

Quote
3) hold the tail while you make tail inputs (make sure the servo is in good working order)

If I hold the tail and make rudder inputs (in rate mode), the body of the heli will rotate (tail can't move as I am holding it, so boom kicks out)

Quote
4) make sure the belt is not slipping.

I don't believe it is slipping, but not really sure how to test this. If I manually rotate the head, the tail turns. How else do you verify that the tail is not slipping?

I am going to the flying field on Saturday morning, so if I don't have it resolved by then, I'll have one of the experienced pilots take a look at it.

05-29-2008 06:32 PM

kcass518
Veteran
Location: Manhasset, NY - USA

I just tapped into this thread. Has anyone addressed the point that 9mm from the center of the servo to the ball link might be a bit much? I don't have my TRex with me, but my memory tells me that I'm at about 5.5 or 6.5, and that this distance was pretty critical. Sorry if my memory is weak, but since you've spent so much time on this I didn't want it to wait until I got home to double check it. Does anyone else have their ball link at 9mm? Hope this helps.

PS I think this is what Zaneman meant in Point #2 - move the ball link closer to the center screw. I actually drilled a hole in my servo wheel because none of the stock holes was close enough - I do remember that!

05-29-2008 06:59 PM

Skarn
Senior Heliman
Location: Pasadena, MD

Hey bro,

One thing to consider is not only the physical location of the ESC itself, but the routing of the wire going from the ESC to the receiver. I had my gyro wire touching that one once and had all sorts of issues. I then routed them on opposite sides of the heli and it corrected it.

One question: When you say it slowly drifts....how slow? If in a hover, how long would it take to fully piroette around 360?

Someone also mentioned low headspeed. Hmmm who was it...not HeliSmith....who was it?

That could be the ticket! What throttle curves are you running?

Skarn

It's better to burn out than to fade away...

05-29-2008 08:03 PM

helimatt
Elite Veteran
Location: Lafayette, IN

I just read up here and have a couple things you might try:

1. My 9257 worked best (on a MiniTitan, not trex, haven't tried it there yet) with the ball further out on the arm, not closest in. Sorry, don't have the exact distance. When I tried it furthest in, I had the gain to 100% (futaba radio) and it didn't hold super well, and no wag. Putting the ball further out on the arm INCREASES MECHANICAL GAIN. I then turned the transmitter gain down, and got a good hold. Higher gain could make it wag.

2. You noted about 30deg drift in 10-15 seconds, which is not super bad, but I had a similar issue with a 401 on my Trex 600, tried a lot of different mountings, gain, tail blades etc. I would add a click or two of trim but it would later drift again.- finally just swapped in a different gyro, and the drift went away. It might have been vibration-related but I couldn't detect any objectionable vibes.

I think that some 401's get out of calibration. The electronics have tolerances afterall. I am not the only one who has had this go on with a 401 and it was the gyro's problem in those cases.

3. If you are not wagging, then don't worry about burning up the tail servo.

4. If the HH light goes on and off as you flip the gear switch, you have it plugged in correctly and the transmitter is setup right.

5. In all cases vibration and/or poor gyro mounting is your enemy.

(I'd still set it up in rate mode, but that's my opinion.)

Never, ever, ever, ever give up.

05-29-2008 08:15 PM

JRjoe
Elite Veteran
Location: Portage, IN

JRjoe

05-29-2008 08:43 PM

nmrs
Senior Heliman
Location: Austin, TX

problem solved

First off thanks to everyone for their infinite patience with me.

Quote
One thing to consider is not only the physical location of the ESC itself, but the routing of the wire going from the ESC to the receiver. I had my gyro wire touching that one once and had all sorts of issues. I then routed them on opposite sides of the heli and it corrected it.

First I tried this. I rerouted all my motor and esc wires to one side of heli and moved all the gyro wires to the other side. Flying it, it seemed a tad bit better, but was still drifting. The tad bit better may have been wishful thinking.

Quote
Someone also mentioned low headspeed. Hmmm who was it...not HeliSmith....who was it?

After a frustrating first flight after rerouting the wires, I came back and reread the thread. I think headspeed was the culprit. I was always flying in normal mode. My throttle curve is 0, 50, 85, 92.5, 100. Due to my complete and utter lack of collective management skills, I'm pretty sure I was occasionally (if you define occasionally as very often

) bringing stick below 50% -- headspeed dropped, tail moved to left. After realizing this, went and flew a battery in idle1 (100, 92.5, 85, 92.5, 100). I got stick up to 50% in normal to spool up the head, then switched into idle1 on the ground, lifted off, and drift was gone.

Thanks again everyone for all the help!

05-29-2008 08:52 PM

SkyWarp
Senior Heliman
Location: Planet Earth

Word of wisdom

I see this type of thread on the little rex all the time. Funny thing is, it turns out to be several pages for what suppose to be a simple solution that is already said by Barracuda and suggested by Zman. It was a month or so ago when I witnessed a 600N piro out of control do to gyro failure. The guy apparently came prepared because he slapped a replacement on, popped the servo arm, stuck that sucker in rate, centered his slider, re-installed his servo arm and was done with the entire process before my battery was even done charging. My setup is similar on my Swift16 but not nearly as fast because of my old age. Cant do those NASCAR tire changes anymore. But with all that aside, someone needs to really pick and choose who to listen to when advice is given. I’m not defending no one, nor am I saying that old geezers know everything (no offense Barracuda), but I’ve already been proven wrong more than once trying to challenge these guys because they’ve been there and done that folks. One day, you will be in there shoes trying to convince some young pilot who claims he’s been around and look back realizing that you were the same way. I personally wouldn’t argue with these guys for the simple fact that there doing everyone a favor by saving you the troubles. I feel privilege when one replies to my post. But again, that’s just me.

Anyway, happy flying.

Century Swift-
I was born at night, but I wasn't born last night.

05-29-2008 08:55 PM

SkyWarp
Senior Heliman
Location: Planet Earth

In addition, for all of you newbies (no point intended).. browse around in the radio sections or categories where most of these guys hang around answering more of the technical aspects of the hobby. If you can honestly say that they still don’t know what they’re talking about then I stand corrected. In the meantime, lets recheck ourselves folks and start treating these guys with some courtesy. I’m not singling anybody out here or this thread in particular. I just thought this would be a good spot to mention this because its happening quite frequently.

Ok, I’ve said enough on the topic and getting off my soapbox.

Century Swift-
I was born at night, but I wasn't born last night.

05-29-2008 09:16 PM

nmrs
Senior Heliman
Location: Austin, TX

Now the drift is issue is mostly solved but I am seeing another drift. When I raise pitch and heli rises, tail drifts a bit to the right, then when I bring the pitch stick back to mid stick, tail evens out to where it was before I climbed. Inverse happens when I bring the heli down in altitude. As it comes down, tail drifts a bit to the left (maybe 20 - 30 degrees), but when I stop descending, tail moves back to where it was before I was descending. Is this normal (tail blowing out a bit right when climbing and left when descending)? Is this also a headspeed issue? I am running 100 - 85 - 100 now with a 12-tooth pinion. Motor is the Align 430xl.

05-30-2008 01:30 AM

Zman9545
Veteran
Location: The Golden STATE

Try this...... start over and redo your mechanical setup as per Barracuda rate method. After that, run a fairly high headspeed just so you can witness that you will no longer experience drift during climbouts. Mind you that the heli will be a bit sensative so tone down by adding some expo and or flybar weights if needs be. I really think your problem resides in both your mechanical setup and throttle/pitch curves programing.

Trex600N Pro
Kinetic 50

-The ONLY way you fail is when you quit.-

05-30-2008 02:51 AM

Blade_Master1
Key Veteran
Location: Canada

I have tried every mode on the align ESC for me I find my heli runs best in governor mode @ 100% throttle with tail servo horn set at the 2nd hole out
100% flat curve in governor mode with the 11t pinnion
switch to the 13t, after you can fly well the use the bigger head spacers when your ready for 3d

try that, I used to have problems until I started running full throttle

I also use the gyro menu and have the gain set to 76%
Since I only fly in HH mode so I did the setup the Finless bob way.

start to end no drift issues

JM2C's :)

05-30-2008 02:51 AM

nmrs
Senior Heliman
Location: Austin, TX

Quote
Try this...... start over and redo your mechanical setup as per Barracuda rate method.

I pretty much did that yesterday when following HeliSmith's very detailed instructions. In rate mode, slider is centered, limit is adjusted on the gyro so that it gets ever so close to binding on both sides without binding.

Quote
After that, run a fairly high headspeed just so you can witness that you will no longer experience drift during climbouts.

Tomorrow I will do a couple of headspeed tests. First I'll up from 100 - 85 - 100 to 100 - 90 - 100 and 100 - 95 - 100 if necessary to see if that gets rid of the climbout drift. If that doesn't do it, I'll try Blade Master's governor suggestion. As for the tail servo horn, my 9257 only came with 3 horns: the round one I am using, a 6-pointed star, and a 4-pointed star. Both stars hit the boom when the servo moves, so I think the round one is my only option. Blade, what servo and horn are you using?

05-30-2008 05:01 AM

Blade_Master1
Key Veteran
Location: Canada

IM using a Hitec hs56
your allowed to trim the servo horns

if your throttle is below 75% in governor mode your tail will wag
I was intimidated by high head speed too
1 last suggestion getting the plastic or carbon blades
LOSE those wooden blades they are dangerous IMO
I have had 1 pair of woodies explode on me already

JM2C's :)

05-30-2008 11:26 AM

Funky Trex
Key Veteran
Location: Westerville, OH - USA

Strange... my results have been different. I never could get gov mode to work well on the Align ESCs. It always seemed to hunt more than just using flat curves in airplane mode. The hunting also played havoc on my tail. I have even tried it on a few different versions of the ESCs but they all seemed to have the same hunting problem although the newest version was slightly better... but it still worked better overall in airplane mode when running back to back flights in both modes.

I also love the woodies. The carbons fly better, but the woodies are great for practicing new tricks. I have run them at 3000+ for well over a year with only one set exploding in air (after previous damage from a tipover). If you are just learning, I would stick with the 325 pros for a while.

05-30-2008 03:16 PM

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Beginners Corner > how much gain is too much?

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