Topic Subscribe
WATCH  2 pages [ <<    <    ( 1 )     2     NEXT    >> ]2655 viewsPOST REPLY
HeliProz . Boca Bearings . Encore RC
. .

e-
Align T-REX Electric Series
 >

T-REX 450
Setting up 401 Gyro to hover in rate mode first - why?
ov10mechHeliman - Lake County, Illinois -

I have been using 401s exclusively on 4 helis for the past year. I have had them on a 450, 500, Raptor 50, and even my Raptor 90. I have had no issues when used with Futaba Digital Tail Servos. Someone was telling me that you are supposed to hover in rate mode when you center the servo and set it with just enough pitch so the tail doesn’t drift. I confirmed this by reading an article on Trex Tuning. I have never done this. I put the thing in rate mode and mechanically center the tail at 0 pitch with the servo arm 90 degrees. I set the limits, go into HH mode, then I fly. All I ever have to do is maybe adjust the gain. So I understand that if you want to fly in rate mode then putting some pitch on the tail in rate would make perfect sense. What’s the point in setting it up to hover in rate mode without any rudder input? I am not disputing it , but none of the guys at the field could explain it other than saying “that’s what they read”. I am just the type of guy that needs a reasonable explanation on why to follow a specific setup best practice. If someone could help me understand why this is required I will join the rate mode setup club

05-11-2009 Over year old.
HOMEPAGE  
Anthony.L

Elite Veteran

Seattle, WA

For the past 2 years I did the same thing as you, put the tail servo arm 90 degrees, center the tail pitch slider, and go fly. However recently I went through the steps to adjust tail pitch until the tail stops drifting in rate mode.

If you think about it, this will also reduce stress and work on the servo. If the servo center is 0 pitch, and the tail needs say 4 degrees of pitch to hold a hover, then the servo is always working. However if you have 4 degrees of pitch at servo center the servo is doing less work to hold a hover. This is strictly my theory, I have nothing to back it up.

When you are adjusting in rate mode, do not use sub trim on the radio! Either move the servo forward/back on the tail boom, or shorten/lengthen the tail control rod.

Bottom line I found the gyro performance to be better with going through these steps, especially in piro speed consistency left vs. right.

05-11-2009 Over year old.
Skarn

Veteran

Pasadena, MD

If you think about it, this will also reduce stress and work on the servo. If the servo center is 0 pitch, and the tail needs say 4 degrees of pitch to hold a hover, then the servo is always working. However if you have 4 degrees of pitch at servo center the servo is doing less work to hold a hover.
This is not true. A servo requires no more power to hold any given position and is not "working" when at a given postion..it's no different from center 0 pitch to 4 degrees...

Also, if you set up for a rate mode drifltess hover, you won't have equal travel on the slider due to the tail geometry of the trex 450 and the single limit pot on the gyro.

There simply is no benefit to setting it up for a rate mode drifless hover on a trex 450 unless you plan on flying in rate mode.

I've tried both ways just to experience it and the tail did not hold any differently either way.

Skarn

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

05-11-2009 Over year old.
Micro-Maniac

Elite Veteran

Pasco,Washington Formerly: Captain Chaos

I'm pretty sure I've tried it both ways and didn't notice a differnce either but I do still like to set it up driftless in rate mode if for nothing else than to neutralize the tail at the flip of a switch after walking the heli out to the launch and I can do this and still get full travel by rotating the servo arm one spline forward on the servo to get more throw one direction than the other and it works out great

In otherwords I center the servo and orientate the arm so that it's 90° then rotate it one spline forward so the rotational arc of the arm will have shorter pull one direction and longer push the other direction

Start with low limit to trim the tail in hover then increase the limit afterwards - If that orientation doesn't work out try another until it does (move the ball to another limb and rotate it to one spline forward from 90° again)

Both worlds - No drift in rate mode and full pitch slider travel both directions without binding

05-11-2009 Over year old.
relax1

Senior Heliman

Tampa, FL

I have always setup on rate mode found the pirouting more consistance and heading hold performance better. Now if your having luck your way just keep doing it.

Luis

05-11-2009 Over year old.
Anthony.L

Elite Veteran

Seattle, WA

This is not true. A servo requires no more power to hold any given position and is not "working" when at a given postion..it's no different from center 0 pitch to 4 degrees...
Whether my theory was correct or not, the reality is every gyro I've done this on has performed better afterward.

Also note that in the manual for the Spartan and Futaba gyros, it tells you to adjust trim in rate mode for a stable hover during setup.

05-11-2009 Over year old.
ov10mech

Heliman

Lake County, Illinois

Thanks

Thanks for all the responses.. I do love a good debate. I think it would make sense for this to be in the user setup manual because the gyro is indeed a Rate and HH gyro, so they want it to fly well in either mode. At the moment, my tails are locked on the 450, 500 , and 90 and dont think I will be changing my ways anytime soon unless there is good reason to do so. I just wanted to make sure I wasn't missing out on something major or if I was doing something that would cause me a problem.

05-11-2009 Over year old.
HOMEPAGE  
TRex888

Veteran

Monmouth, UK

Also note that in the manual for the Spartan and Futaba gyros, it tells you to adjust trim in rate mode for a stable hover during setup.
Except Spartan's own FAQ counter acts against this http://www.spartan-rc.com/resources....php?category=2

05-11-2009 Over year old.
172AMD

Heliman

Richmond, B.C. Canada

"Also, if you set up for a rate mode drifltess hover, you won't have equal travel on the slider due to the tail geometry of the trex 450 and the single limit pot on the gyro".

Skarn, You are wrong about this! On my Trex600 with the tail pitch slider all the way to the left: 34.6 degrees pitch. Tail pitch slider all the way to the right: 24.4 degrees pitch.
The tail pitch geometry of the Trex600 is designed for some left pitch when the pitch slider is centered, so you will get equal pitch travel in both directions. This was the same on my Trex450. It is also this way on my TT e620se, and TT mini Titan.

05-12-2009 Over year old.
Skarn

Veteran

Pasadena, MD

Skarn, You are wrong about this! On my Trex600 with the tail pitch slider all the way to the left: 34.6 degrees pitch. Tail pitch slider all the way to the right: 24.4 degrees pitch.
The tail pitch geometry of the Trex600 is designed for some left pitch when the pitch slider is centered, so you will get equal pitch travel in both directions. This was the same on my Trex450. It is also this way on my TT e620se, and TT mini Titan.
No, I'm not wrong about this. With a trex and the slider mechanically centered, the pitch is zero. At least with a 450 and 500...I don't have a 600. This is not an opinion is is a fact. So if you setup for a driftless hover in rate mode, you will no longer have a centered slider.

Also it appears in your first picture you have confirmed what I was saying....you have zero pitch with slider centered...but admittedly it's hard to see the slider from that pic.

Skarn

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

05-12-2009 Over year old.
Micro-Maniac

Elite Veteran

Pasco,Washington Formerly: Captain Chaos

I gotta agree with Skarn as far as the T450 tail geometry - When using a GY401 I offset my servo arm to equalize the left/right slider travel from the torque offset position of the slider on the output shaft - When the tail is torque trimmed the slider is not centered

05-12-2009 Over year old.
Funky Trex

Elite Veteran

Westerville, OH - USA

The "set up in rate mode" argument will never end

05-12-2009 Over year old.
Skarn

Veteran

Pasadena, MD

Here is a great explanation from Finless Bob about the Align Heli's:

Well a big problem some of you guys are quoting is it is not possible on a Trex 450 to have the slider centered and have it hover in rate mode! Geometry of the tail gives you 0 tail pitch when slider is centered PERIOD.

"Airjawed, I think you are getting confused between actually FLYING in rate mode vs setting up the linkage while the gyro is in rate mode. To fly (hover) while the gyro is in rate mode, the slider will be offset from center with the servo arm 90.

So if you setup for rate mode hover, you will move the servo on the boom until the heli hovers and the tail doesn't drift. Once done and you have that, if you power off the heli and power it back up in HH mode you will see when the gyro inits and puts the servo center (90) the slider is offset. Now you have to adjust the limit pot on the 401 so you don't bind in either direction. Once done with that you will see the slider will NOT travel fully in one direction.

MOST OTHER HELIS do not have this kind of geometry! The 401 was made long before Align made helis with 0 pitch center slider geometry and setting up for rate mode hover was easy as the geometry of most heli tails gives you close to the right amount of pitch to compensate for torque when the control arm for the slider is 90. The 401 instruction were written for helis with rate mode pitch built in the tail geometry."

Skarn

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

05-12-2009 Over year old.
Micro-Maniac

Elite Veteran

Pasco,Washington Formerly: Captain Chaos

It's only an arguement between people who never use rate mode - For scale pilots etc who actually do fly in rate there is no arguement - They must get the geometry dailed no ifs ands or buts about it

05-12-2009 Over year old.
Waco

Senior Heliman

Bernalillo, New Mexico USA

I also tried both with and without rate mode trim. However, I find that having the rate offset prevents loss of heading hold in when spooling up on hard surfaces. Otherwise the heli will sometimes spin the tail out of limits and requires switching back between rate & HH to reset the gyro. Yes I use soft start and I always put the offset in after binding the TX so that the gyro will maintain the same servo travel limits in both directions.

05-12-2009 Over year old.
ov10mech

Heliman

Lake County, Illinois

Waco, I agree that my helis do spool up on ground the with a slight drift until the headspeed is up there. I am just used to it and give a tad input to correct it. Would never bother me enough to do anything about it. All I personally care about is full balls out idle up with Heading Hold. The only mode I ever fly in

05-12-2009 Over year old.
HOMEPAGE  
172AMD

Heliman

Richmond, B.C. Canada

"Geometry of the tail gives you 0 tail pitch when slider is centered PERIOD."
Not on my Trex 600! I no longer have my Trex 450, but it was the same.
I agree to disagree.

05-12-2009 Over year old.
baddynergy

Elite Veteran

sierra madre, ca- usa

IMHO you do NOT need equal travel. It naturaly spins nose left so it obviously need more throw the opposite way to counteract. Setting it up in rate mode is just one more step to a finely tuned machine. The piros are more consistent if set up in rate mode. And it will hold better.

I like Bobs videos but this one he got wrong. Trying to cut a corner for ease of set up is not the best way to a locked in consistent tail. Futaba (you know the manafacturer) says to set it up in rate mode.

**Unattended children will be givin a shot of espresso and a puppy**

05-12-2009 Over year old.
172AMD

Heliman

Richmond, B.C. Canada

"Also it appears in your first picture you have confirmed what I was saying....you have zero pitch with slider centered...but admittedly it's hard to see the slider from that pic."

No, the slider in that picture is not centered. The next picture shows full left slider travel [34.6 degrees left pitch]. And the last picture shows full right slider travel [24.4 degrees right pitch]. This should tell you that the slider is not centered in the first picture.

Again, I agree to disagree.

05-12-2009 Over year old.
Helico-pteron

Veteran

Glenview, Illinois

Mechanically center, set up in rate mode.

Done

Why argue about it?

05-12-2009 Over year old.
WATCH  2 pages [ <<    <    ( 1 )     2     NEXT    >> ]2655 viewsPOST REPLY
ExperienceRC . JR AMERICAS . HeliDirect
. .

e-
Align T-REX Electric Series
 >

T-REX 450
Setting up 401 Gyro to hover in rate mode first - why?
 Print TOPIC Advertisers 

Topic Subscribe

Friday, October 31 - 2:16 pm - Copyright © 2000-2014 RunRyder   EMAILEnable Cookies