rrTV-PHOTO   New HD TV
HOME   rrTV-PHOTO   GALLERIES   MY GALLERY   HELP-FAQ
myHOME PM pmRR MEMBERS 596 ONLINE 72 EVENTS SEARCH REGISTER  START HERE
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]944 viewsPOST REPLY
MTA Hobbies . MRC/Altech Marketing USA . Next D

.
.
Main Discussion > I have two questions/ 2 head speeds in the same mode???
 
 
RcNutTz
Heliman
Location: Chicago Illinois USA

Hi, every one

I have A T-Rex 450SE V2 with a 401 gyro in a steady hover the tail wags (side to side a inch or so) With the help of a friend we turned down the gain to around 26 on a DX7 it has got a little better but still does it he told me 26 was pretty low? any one with this combo tell me what your is set at?


When I start it up some times it will lift off about half stick (throttle) and other times it takes more? you can see the blade speed and hear when its lower at time is some thing wrong? if so what? or what should I look for?

Thanks
Bob

I have found out in the same mode I get 2 head speed @ 1/2 stick just from spooling up not changing any thing (not flipping any switches) just spooling up and once while in flight hovering it changed to the higher speed on its owen

bad esc????

I fly (I smile) I crash (I'm sad) I repair & Fly (I smile) Wife sees credit Card bill (I run )
05-06-2008 12:34 AM
 
 
ckoelliker
Key Veteran
Location: St. Simons, GA

For the first problem, what is the length of the servo horn on your rudder servo. If it is too long you will get a low gain. 6-8mm is a good place to start.

As for the head speed issues, it could be as simple as a bad battery, or you could be running the Align esc in gov. mode which has caused problems for some people. What is the set up? IE motor, battery, pinion, esc, throttle curve, etc. Do you know your head speed?
05-06-2008 12:46 AM
 
 
Skarn
Senior Heliman
Location: Pasadena, MD

A gain of 26 in the DX 7 gyro menu means it's in rate mode...above 50 percent it's in HH mode. Are you using the gyro sense menu or gear ATVs?

Skarn

It's better to burn out than to fade away...
05-06-2008 05:08 AM
 
 
RcNutTz
Heliman
Location: Chicago Illinois USA

Hi, thanks for the reply!

I'm still new at this so I might not know every thing you asked

holes are 10.51mm apart on the gyro Servo arm from center mounting hole to hole where tail control rod ball linakage is mounted

The motor is the stock Align 430XL The ESC is also the stock 35amp, main gear is 84t, pinion is 12t


the throttle curve is bumped a little 25%/31, 50%/62, 75%/81, 100%/100 (if this is what you mean?)


Skarn, thats in HH mode 26, I'm not sure how the radio is set up he's the radio guy I still dont get it, But if you tell me what to look for in the radio I can see if I can find out for you ?

thanks

I fly (I smile) I crash (I'm sad) I repair & Fly (I smile) Wife sees credit Card bill (I run )
05-06-2008 05:33 AM
 
 
RadioFlyerMk
Senior Heliman
Location: Trenton, Ohio,

You should also check your mechanical setup. Make sure there is no friction on that control rod. Remove the rod from the servo end and check it with your fingers, you want no friction.
Was the linkage and everything setup in non heading hold mode? Meaning. in non heading hold mode, the light is off onthe gyro, you can lift into a hover without the tail whipping around. If not you will need to do that.

Sounds like watching a setup video on the other site would be very helpful to you. PM me if you want any details.

-----------------------
"I'd rather hover a Heli......than fly a plane"
05-06-2008 06:18 AM
 
 
alf1096
Senior Heliman
Location: TX

On my 50 nitro I run the gyro through gear with an endpoint of 73-78.
05-06-2008 03:01 PM
 
 
speeddemon370
Senior Heliman
Location: Spruce Grove, Alberta, Canada

Many esc's have a "slow start" safety feature. Basically for the first 15secs of operation the thing will spool up very slowly instead of just going to the stick position. It is entirely possible to lift off before the esc get's past it's safety timeout. I would imagine this is where you're "take off vs stick position discrepancy" is coming from.

As for your gyro setting. I'd say the mounting on your servo horn is the issue. Just like ckoelliker said.

with 2 ears and 1 mouth you should listen twice as much as you talk
05-06-2008 05:23 PM
HOMEPAGE  
 
 
RcNutTz
Heliman
Location: Chicago Illinois USA

I will change the servo and update the post

thanks for the input!

I fly (I smile) I crash (I'm sad) I repair & Fly (I smile) Wife sees credit Card bill (I run )
05-06-2008 10:45 PM
 
 
RcNutTz
Heliman
Location: Chicago Illinois USA

Update: Today I took my 401 gyro off my raptor and installed it on my Trex 450 to see if it was the gyro, Same wag with my other gyro so at least we know its not the 401 thats the problem. Servo checks out ok also

inspected the belt looks good, nothing binding in the linkage

The gyro is set on "gear" in my DX7

any more ideas? this got me pulling my hair out and its not good I'm balled

I fly (I smile) I crash (I'm sad) I repair & Fly (I smile) Wife sees credit Card bill (I run )
05-08-2008 06:02 AM
 
 
speeddemon370
Senior Heliman
Location: Spruce Grove, Alberta, Canada

Check for "slop" or "play" in the tail rotor linkage or your push pull link. Other than that, turn your gain down till it stops wagging. So what if you have to have it turned down lower than normal. If it works it works right?

with 2 ears and 1 mouth you should listen twice as much as you talk
05-08-2008 04:03 PM
HOMEPAGE  
 
 
biglarry
Heliman
Location: ME

Had this problem once and found out that it was caused by my tail grips being too tight so my tail rotors were causing an unballance. not saying this might work but its a thought.
05-08-2008 04:10 PM
 
 
RcNutTz
Heliman
Location: Chicago Illinois USA

their is a very little amount of "play" in the tail linkage all move freely dont feel any type of binding?

the wag comes and go's but its their about 50-60% of the time wags about 1/2" to 1" (side to side)

I just dont get it?

401= Good
Servo= Good
Belt= Good
Linkage= Good
Contections= Good

I'm gonna try to change out the ball ends on the linkage and loosen up the blade grips on the tail see if that will fix it

can this be caused by some thing on the main frame? head? motor? Esc?

I fly (I smile) I crash (I'm sad) I repair & Fly (I smile) Wife sees credit Card bill (I run )
05-08-2008 04:28 PM
 
 
speeddemon370
Senior Heliman
Location: Spruce Grove, Alberta, Canada

I don't think it can be caused by the head. Any type of delay from the gyro ot play in the linkage will cause tail wag. Basically it's created by the gyro correcting the tail and telling it to go one direction, the tail obliges and then the gyro stops it once it's happy with the position, what's happening is your tail is going too far or it's taking too long to stop so now it has to go back the other directon, but once again it takes too long to stop so now it has to go back the other direction. Viscious circle but you're gonna have to figure it out. I would think the play in your linkage would be the culprit. I would also be tightening up stuff at this point not loosening it but who knows. Try moving the push pull linkage closer to the axis of the servo. (move it inward a hole or 2 on the horn) Maybe that will help.

You still haven't mentioned if you just turned the gain down some more. Does that fix it?

with 2 ears and 1 mouth you should listen twice as much as you talk
05-08-2008 04:57 PM
HOMEPAGE  
 
 
Helinorth
Senior Heliman
Location: Terrace Bc Canada

I had something similar on my new se but it only twitches at about 80% throttle.tried gyros head balance etc but still there .the easy fix was to just up the curve above 80 before lift off in normal and go 100% in idle 1.It will wag a little while on the ground going past the 80% mark and then it's fine.I also noticed that the tail pitch slider seems to move back and forth slightly on the tail shaft as it is rotating like the bushing was not installed in the slider straight.i thought this might also be causing it but haven't got around to changing it yet.
05-08-2008 05:08 PM
 
 
ckoelliker
Key Veteran
Location: St. Simons, GA

This is a long shot at best, but if you are using the 3M red backed double sided tape to secure your gyro. You should try switching it out. To see if that helps.
05-08-2008 05:10 PM
 
 
RcNutTz
Heliman
Location: Chicago Illinois USA

I did have the gain down to 20 and it was almost gone, but every one tells me thats way to low some things wrong if it has to be that low?

I did switch the mounting tape no help with that

I fly (I smile) I crash (I'm sad) I repair & Fly (I smile) Wife sees credit Card bill (I run )
05-08-2008 05:12 PM
 
 
helimatt
Key Veteran
Location: Lafayette, IN

Move to the closest in hole on the servo arm. Should help a lot generally- only exception I've had so far is a JR 3400G servo, which I had better results with the ball on the second hole out (cannot remember the actual distance from servo center).

What tail servo and what tail blades are you flying- both will have a profound effect on the tail performance.

Never, ever, ever, ever give up.
05-08-2008 05:14 PM
 
 
RcNutTz
Heliman
Location: Chicago Illinois USA

JR 3400G tail servo 10.5mm distance right now (2nd hole out) & stock white tail blades

I do have some carbon tail blades i'll try swapping them out and see if that helps?

I fly (I smile) I crash (I'm sad) I repair & Fly (I smile) Wife sees credit Card bill (I run )
05-08-2008 05:16 PM
 
 
ckoelliker
Key Veteran
Location: St. Simons, GA

You are still at 10.5mm. You need to try moving it in. Try around 6-8mm. I think that is the problem.

This is from the spartan gyro website. It does a pretty good job of explaining briefly, the relationship between the servo arm length and gyro performance. Essentially "mechanical gain".




Quote 
It is not uncommon to find that the optimal gain value for a helicopter may be a small number such as 35-45%. The small value does not mean that the gyro will be limited in performance. Any gain value performs well as long as it is the optimal gain value. However, a gain below 35% indicates that the mechanical gain of the tail is too high and it is therefore recommended moving the servo arm ball link further in. Similarly if 100% is reached and no tail wagging is seen the ball link needs to be moved further out and repeat the gain adjustment procedure. The previously indicated 35% is for guidance only. There are significant variations in the tail design of helicopters and in some cases it may be deemed essential to use a value below 35%.
05-08-2008 06:06 PM
 
 
speeddemon370
Senior Heliman
Location: Spruce Grove, Alberta, Canada

If it gets better as you turn your gain down there is no problem imo. It's six of one and a half dozen of the other. Less gain and or moving the mount in on the servo horn do approximately the same thing. If 20% gain was too low to be used the gyro wouln't come with it in it's adjustment range. I think you may be making a really big deal over nothing. Turn the gyro down and fly the darn thing!

with 2 ears and 1 mouth you should listen twice as much as you talk
05-08-2008 06:23 PM
HOMEPAGE  
 
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]944 viewsPOST REPLY
Futaba-RC . Fast Lad Performance . Esprit Model

.
.
Main Discussion > I have two questions/ 2 head speeds in the same mode???
  UPDATE SCREEN   PRINT TOPIC Advertisers 

Subscribe to This Topic

Saturday, May 17 - 8:06 pm - Copyright © 2000 - 2008 runryder.com | email | link to rr | runryder needs cookie