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CarbonXtreme . Midland Helicopters . HeliProz

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Main Discussion > tail rotor out of control on trex 450, cheap servo
 
 
helismasher
Heliman
Location: Chadron, NE

T-rex se v2 with cheap tower pro servo on rudder. Align head lock gyro. It acts like the gyro is over conpensating (tail swings back and forth violently when pitch is applied). is this because of the slow servo? .3 sec @60 degrees
05-10-2008 11:07 PM
 
 
speeddemon370
Veteran
Location: Spruce Grove, Alberta, Canada

No, it's because you have the gain set too high. Turn it down bit by bit till the wag goes away.

with 2 ears and 1 mouth you should listen twice as much as you talk
05-10-2008 11:09 PM
HOMEPAGE  
 
 
3kidzheli
Heliman
Location: columbia, ms usa

have friemds with se and one in particular does hard 3d and he used slower servo at first but had to upgrade... same prob but if decreasing gyro gain does trick fly it but if it doesnt get a good dig servo and a fast one... that heli will hold like the big boys when set up right.

Theirs no such thing as up, it's all out...
05-11-2008 04:04 AM
 
 
helismasher
Heliman
Location: Chadron, NE

I put the gain all the way down and it didn't seem to make a difference, can't see any difference all the way up either. Do I have to find a spot in the middle some where that works? I've got the gyro mixing and revo mixing off on my transmitter (6exhp), doesn't seem to help.
05-11-2008 04:57 AM
 
 
RcNutTz
Senior Heliman
Location: Chicago Illinois USA

I have the same problem right now with a 450 se v2/ Gy401 w/3400g servo

So far a swapped the 401 from my Raptor, changed to s9257 servo, installed new out put shaft in tail, adjusted gain +/-, looked for binding linkage, used a diferent brand dubble side tape and still have a slight amount of wag

Just cant seem to find the problem only thing left if change the tail blades??? I plan on trying that tomorrow

Bob

I fly (I smile) I crash (I'm sad) I repair & Fly (I smile) Wife sees credit Card bill (I run )
05-11-2008 05:47 AM
 
 
cassat
Veteran
Location: Alberta,Canada

Yeah, add me to the list. Mine has the wag also. Had 3 flights trying to lower the gain also after setting up the Telebee in rate mode first.
Mine had a bite on the tail shaft so I used Tri Flo to lube it. Will try it tomorrow and maybe new tail blades also.
05-11-2008 05:51 AM
 
 
helismasher
Heliman
Location: Chadron, NE

mine to me acts like the servo. It has for of these: Towerpro-SG90 Mini-Servo

Item# Towerpro-SG90
Sale price: USD$9.99



Product Description
SG90 weight- 9g
Dimension 23x12.2x29mm
Stall torque 1.5kg/cm
Operating speed 0.3sec/60degree(4.8v)
Operating voltage 4.2-6V
Temperature range 0¡æ_ 55¡æ
Dead band width 10us



First time setting up a good heli so i'm shooting in the dark a little.
05-11-2008 05:54 AM
 
 
speeddemon370
Veteran
Location: Spruce Grove, Alberta, Canada

If you can turn the gain all the way down and all the way up without noticeing a difference you have some major issues. For example, a gyro not working at all! Seriously, the gain should solve or at least help your situation. If it dosen't, start swapping stuff out till you find what's doa.

with 2 ears and 1 mouth you should listen twice as much as you talk
05-11-2008 05:55 AM
HOMEPAGE  
 
 
speeddemon370
Veteran
Location: Spruce Grove, Alberta, Canada

What hole do you have the linkage attached to on the servo horn. Eg, is it close to the pivot or towards the outside. On a slow servo it should be as much to the outside as possible. 10mm from the shaft is normal I believe. You can somewhat compensate for a slow servo by moving the mount farther out from the axis. Maybe even putting on a bigger horn.

with 2 ears and 1 mouth you should listen twice as much as you talk
05-11-2008 06:05 AM
HOMEPAGE  
 
 
dkshema
rrProfessor
Location: Cedar Rapids, IA

Quote 
I've got the gyro mixing and revo mixing off on my transmitter (6exhp), doesn't seem to help.

Revolution mix OFF -- that's a good thing...

...but...

You turned off the gyro mix in your transmitter. Are you using thought control to run the gain on your gyro, or just crossing your fingers and hoping it will all turn out OK?

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A quick read of the 6EXHP manual and a couple of different Align gyro manuals tends to tell me that getting your gyro to work is not a difficult task.



Plug the single-wire plug from the gyro into channel 5 of your receiver.
Plug the three-wire plug into channel 4 of your receiver.
Plug the servo into the remaining plug of the gyro.

Enable the Gyro menu in your TX as per the picture above.

One position of the channel 5 control switch on your TX will put you into HH mode, the other position will put you into Normal mode.

To figure out WHICH mode you're in, turn everything on, let it initialize, then move the rudder stick side to side, and let it return to neutral. If the servo follows the stick and returns to neutral, you're in NORMAL mode. If the servo "kind of follows the stick", but doesn't return to neutral when you let go of the stick, you're in HH mode.

Adjust the gain numbers for each position to something like 50% for starters.

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Don't know how long your servo arm is, but somewhere in the neighborhood of 6/7 mm MAX from servo center to output arm seems to be about all the Trex can handle without really going weird on you.

Then you make sure that the pushrod and all of the tail feathers move smoothly and with no drag or friction. If you have anything anywhere that is putting a load on the servo, your Trex will wag its tail like a happy pooch!

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Make sure you have the transmitter AND the gyro commanding the correct direction.

If you built your Rex per the manual, RIGHT rudder command tells the TR servo to PULL the pushrod FORWARD. If it doesn't reverse your transmitter rudder channel.

Pick up the heli, turn the nose to the LEFT while watching the servo. The servo must pull the pushrod FORWARD, toward the nose of the heli. If it doesn't, reverse the GYRO direction.

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Do the mechanical setup correctly.

-----

* Making the World a Better Place -- One Helicopter at a time! *

Dave
05-11-2008 06:09 AM
 
 
helismasher
Heliman
Location: Chadron, NE

it's in the middle hole about 5/16" from shaft, maybe i'll try moving it out. With the head lock gyro i don't want any gyro mixing on my transmitter right?
05-11-2008 06:12 AM
 
 
helismasher
Heliman
Location: Chadron, NE

ok got everything set up and the servo started twitching and locked to one side and got pretty hot. What the? does it matter if the gyro is mounted upside down or not as long as the direction of motion sensed is in-line with the tail? it must be a gyro glitch, i don't know.
05-11-2008 06:52 AM
 
 
helismasher
Heliman
Location: Chadron, NE

Now i'm not getting any response out of my reciver! What the hell?
05-11-2008 07:03 AM
 
 
cassat
Veteran
Location: Alberta,Canada

mounting

helismasher

You cannot mount the Align gyro upside down! It must be mounted with one of the sides of the case on the frame. You might have burned out your servo trying it the wrong way.
05-11-2008 01:44 PM
 
 
dkshema
rrProfessor
Location: Cedar Rapids, IA

Quote 
You cannot mount the Align gyro upside down!

Mounting a gyro upside down will only reverse its operation. If you couldn't mount it upside down, you would never be able to do any aerobatics...

This is a solid state gyro, like all others now on the market, and the sensor is not affected by being upside down. All that matters is that the sensing axis be vertical, parallel to the main rotor shaft.

If your gyro didn't have a reverse switch on it, the way to reverse its operation is to turn it upside down.

-----

If your servo ran to one end and you let it stay there and get really hot, bound up and stalled, there is a good chance you fried the poor sucker. That is why you never want ANY control surface to be stalled at an endpoint.

-----

* Making the World a Better Place -- One Helicopter at a time! *

Dave
05-11-2008 06:14 PM
 
 
helismasher
Heliman
Location: Chadron, NE

servo is toast. I think i better just put down the money for a good hi speed and go from there. These tower pro's chatter a little, they don't seem like very good quality. After i get a little flight time with this thing I can upgrade the other three servos and maybe the gyro. Sound like a plan?
05-12-2008 01:21 AM
 
 
PitchFan
Heliman
Location: Sunny FL

These work well for budget servos on the tail. http://www.heliproz.com/prodinfo.asp?number=103111
05-12-2008 01:51 AM
 
 
helismasher
Heliman
Location: Chadron, NE

How about for swash servos? Should I not worry about the chattering or get something better? And thanks for all the help guys great forum!
05-12-2008 02:47 AM
 
 
RcNutTz
Senior Heliman
Location: Chicago Illinois USA

If I was you, I'd just put better servo's in it now you got a lot of $$ invested you should be able to get some nice servo's in it for under $100 the hitec 65mg is what every one told me to go with but you can get them with the plastic gears and alway change them to metal later

I fly (I smile) I crash (I'm sad) I repair & Fly (I smile) Wife sees credit Card bill (I run )
05-12-2008 02:53 AM
 
 
Way2slow
Veteran
Location: Jeffersonville Ga

I'm running my V2 SE off the gear off a 6200RX and X9303 with the 401 and 9257 servo and if I have my gain much more than 45% it gets the nervous jitters. As long as I run it less the 45% it never bobbles. I am also running the Hitec HS65HB servos on the cyclic.
05-12-2008 04:30 AM
 
 
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Main Discussion > tail rotor out of control on trex 450, cheap servo
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