Setting Up the GP-750 gyro in T-Rex 250 kit

[steph280]

The Align GP-750 heading lock gyro that is included in the new T-Rex 250 super combo kits has setup steps that differ with most other gyros on the market. In order to take advantage of its capabilities, correct options must be set according to the specific application. I will try to walk through the setup steps and explain each setting.

Similar to other gyros, when it is powered up, the LED will flash rapidly indicating initialization is in progress. Do not touch the gyro or helicopter at this point. Once the initialization process completes, the status LED will remain lit in green or red. Green indicates gyro is in heading lock mode, red means it’s in normal rate mode.

Before you start, it’s best to understand what each option means.

• 1520/760: This represents the frame rate of the rudder servo used. Most commonly used analog or digital servos use the 1520us frame rate. 760us rate is used specifically for high frequency servos such as Futaba 9256 and BLS251. If unsure, always set this option to 1520us to avoid burning out your servo. 1520us is also the factory default settings.
• DS/AS: This sets the gyro for either Digital Servo or Analog Servo. DS is the factory default setting.
• NOR/REV: This sets the compensating direction for the gyro.
• Limit: This setting limits the rudder servo travel and is used to avoid binding in the tail linkage.
• Delay: This is the setting used to dampen the gyro compensating speed for slower servos that are unable to keep up, resulting in tail oscillation. There is also an imbedded setting for the size of helicopter used. Small includes 250/450 size, while large includes 500/600/700.


The setup steps involve the use of your transmitter’s rudder stick and the “SET” button on the gyro. You basically cycle through the 5 options with the set button, and select the setting using the rudder stick.

• To enter the setup mode, press and hold the SET button for 2 seconds until STATUS LED flashes.
• While in setup mode, momentary press of the SET button will cycle through each of the settings.
• Select the setting by moving the transmitter rudder stick left or right, and observe the color of STATUS LED.
• When correct color is observed, press the SET button to memorize the setting.
• The gyro will exit the setup mode if left idle for 10 seconds.


Below is the walk through of an example setup. Suppose you will be using this gyro on a T-Rex 250 with Align’s DS420 digital servo.

1. Push and hold the SET button until STATUS LED flashes.
2. 1520/760 LED will lit up
3. Move rudder stick left or right and watch the STATUS LED. Green LED is 1520us, red LED is 760us. Let’s set it to 1520us.
4. While holding the rudder stick and LED shows green, press the SET button on gyro.
5. Now DS/AS LED lights up.
6. Move rudder stick left or right and watch the STATUS LED. Green is for digital servo (DS), red is for analog servo (AS). Let’s set it to DS.
7. While holding the rudder stick and LED shows green, press the SET button on gyro.
8. Now NOR/REV LED lights up.
9. Move rudder stick left or right and watch the STATUS LED. Green is for normal, red when direction needs to be reversed. Let’s set it to normal.
10. While holding the rudder stick and LED shows green, press the SET button on gyro.
11. Now Limit LED lights up.
12. Move the rudder stick and observe your tail pitch travel. Move the rudder stick left until the tail pitch slider reaches the end, then move to the right until pitch slider reaches the other end.
13. While holding the rudder stick, press SET button on gyro.
14. Now Delay LED lights up.
15. Move rudder stick left or right and watch the STATUS LED. Green LED is large helicopter, red LED is small helicopter. Let’s set it for small helicopter.
16. The amount of rudder stick moved from center will determine how much delay is applied. For this example, the Align DS420 servo does not need any delay, so rudder stick can be left centered.
17. While holding the rudder stick and LED shows green, press the SET button on gyro.
18. That’s it!

[ChrisH]

Thanks for the great setup walk-through. Be sure to let us know how this gyro/tail servo combo works out in real life testing as soon as you get that missing bearing!

[CeeveeSiN]

nice info!

[Bobbyk]

I have the GP700 on my T500E and like it, it looks like the difference is the size of the bird you have to select on the GP750. I don't recall that on mine, it sure is better than the 401.

Robert

[Future1]

It also has a metal baseplate (something like that!) to dampen the vibrations. I am most likely going to get the super combo looks like a good deal and good servos/gyro.

Thanks for the info Steph, will come in useful as soon as people get the 250.

[crash1000]

from the programming it looks like a 2100t. If you can get a spartan, go for the spartan.

[10karer]

Originally Posted by steph280

.
11. Now Limit LED lights up.
12. Move the rudder stick and observe your tail pitch travel. Move the rudder stick until the tail pitch slider reaches the end.
13. While holding the rudder stick, press SET button on gyro.
!

This part was confusing on the gp700 instructions as well. If you move the rudder to the left slowly to where you want full travel then to the right slowly untill full travel go back to center and press set it will remember the full travel on both sides.

my $.02

[steph280]

Interesting, I didn't know the limit travel can be adjusted each side separately on this gyro. Thanks for the pointer. I have edited the 1st page to include this.

[bkervaski]

Can anyone confirm this is actually the gyro that ships with the Super Pro Combo kit? Some vendors indicate it's a GP700, not the GP750.

[cgal_1]

I'm trying to set up a GP700 in a trex600.
I've set the ball 10 mm from the centre as suggested, but have way too much movement, stalling the pitch slider. Can I then use the limit setting to reduce this to how far I want the slider to go?
I tried this, but then got part of the stick movement for which the tail didn't move, which didn't seem right.
Should I use end point settings on the transmitter?
I'm new to heading hold gyros. Am I doing something stupid?
Any help much appreciated.
Charles.

[ChrisH]

Originally Posted by bkervaski

Can anyone confirm this is actually the gyro that ships with the Super Pro Combo kit? Some vendors indicate it's a GP700, not the GP750.

My Super Combo came with a GP750.

[stmpngrnd]

Originally Posted by cgal_1

I'm trying to set up a GP700 in a trex600.
I've set the ball 10 mm from the centre as suggested, but have way too much movement, stalling the pitch slider. Can I then use the limit setting to reduce this to how far I want the slider to go?
I tried this, but then got part of the stick movement for which the tail didn't move, which didn't seem right.
Should I use end point settings on the transmitter?
I'm new to heading hold gyros. Am I doing something stupid?
Any help much appreciated.
Charles.

I set my gp700 the same way I used to set jrg550t.

• use the stated servo arm length
• set everything up 90*
• use max travel in the radio
• use the gyro to adjust the endpoints to prevent binding
• then use dual rates in the radio for your piro rates

slow piro rates setup this way will a yield a stick movement where the stick and the servo endpoints are the same(none of the dead stick movement you talk about)

faster piro rates will have differing amounts of that dead stick at the end as you will be using a higher dual rate.

My setup with this gyro on my T700:
30% dual rate in normal - very mellow piro but with full stick movement
45% dual rate in idle1 - pretty darn fast piro with just a little dead stick at the end
55% dual rate in idle2 - holy smokes its a piro blur with about a 1/4 deadstick at the end.

the dead stick really does not matter because you never need full rudder stick movement. ..well atleast I don't and I'm definetly no Zsabo or Riva!

[butters149]

hey i dont get step 16, it says for delay i shouldnt move the rudder stick? but you just said move it to get red to set it for small heli. after that there are no more steps.

[steph280]

you move it left or right to get the green or red led. Then if you want 0 delay, center the rudder stick before pushing the set button.

[alignrcusa]

Steven:
thank you for your setting go through!

one thing that everyone need to be watch out! if you set up T250, do remember set you swash mixing around 40%-45%(40% of swash mixing will give you 10 degree of pitch) tail won't holding good if you set too much of pitch!

[blahblah9]

what is everybody % for the other 2 swash mixing settings?

[cfrankfly]

Originally Posted by bkervaski

Can anyone confirm this is actually the gyro that ships with the Super Pro Combo kit? Some vendors indicate it's a GP700, not the GP750.

GP750 is what came in my Super Combo with all supplied.

[cfrankfly]

Originally Posted by alignrcusa

Steven:
thank you for your setting go through!

one thing that everyone need to be watch out! if you set up T250, do remember set you swash mixing around 40%-45%(40% of swash mixing will give you 10 degree of pitch) tail won't holding good if you set too much of pitch!

Do you mean the "Expo" settings or the "Aile/Elev/Pitch" Swash mix?

I cannot find the setup for that part.

I just bought the super-combo 250 with the Align servos and AlignGP750 gyro hoping to get a great flying bird out of the box.
Since new I have always had a occasional slow "drift" that drifts, and returns to original heading by drifting back, or faster "dog-wag" when increasing
the gyro sensitivity to about 70 ( Spectrum DX6i box).
The tail will acts the same with a Spectrum 2100T gyro as an alternate test.
I notice a small amount of play between the tail rotor blades and the tail slider assembly (new) and cannot tighten down the assembly that I know of.
I seems to me that the Align DS420 servo has the strength to hold but cant figure out how to resolve my symptoms....
Could I ask for your advice?

[growler]

Does anyone know if the delay settings work the same on the GP700?

Meaning the big heli/small heli thing, as well as center for zero delay?

[Mujenpwr]

Originally Posted by alignrcusa

Steven:
thank you for your setting go through!

one thing that everyone need to be watch out! if you set up T250, do remember set you swash mixing around 40%-45%(40% of swash mixing will give you 10 degree of pitch) tail won't holding good if you set too much of pitch!

He means do not use more than 40% to 45% of swash mix for your main blade pitch travel for your CCPM settings.