Gain Settings for Align Gyro

[Aztek1701]

Hi Everybody.

Im very new to helis but very keen. I recently bought a T-Rex 450X and a heading lock gyro to go on it.

Can anybody recommend what the gain settings should be for heading lock / normal mode as mine seems to work in both settings (tail servo drifting towards an end) but when I engage head lock in the hover, the heli turns thru 90 degrees and scares me silly

Thanks in advance...

[JontheRooster]

Unfortunetly, you get what you pay for. I have been told to start out with 100% gain to get tail wag then back off until tail becomes stable. No mater what I did my bird spinned out of controll. Turned out to be a bad gyro,(They are out there!) I mailed back to shop for a return, but, it never got there! So now I have to buy a new one.This one will be the GY401 from Futaba (Quality). My bird has been together for over a month ( collecting DUST)! waiting for a gyro that works!!!!!!

[Aztek1701]

Yeah, I know what you mean, I think my next one will be a Futaba, if for no other reason than it will stick to the mount better than the Align one.

Thanx for the 100% thing. I'll bear that in mind but I think I got it licked cos I turned the Tx gain up to 63% and ajusted it using the instructions I (finally) found on trex tooning and it seems to be better, I'll know tonight cos I plan to drag the thing back to me office workshop to test fly it tonight. Heres hoping I dont kill the thing. lol.

[gpitt]

I have one that works well, you have to set it on it's side, not upright like the directions say or you will crash. Here is a link to trextuning web site. I hope this helps. http://www.trextuning.com/alignhhgyro.htm

Can anybody help me ref. gyro set-up? The trex tuning site is good but assumes that I know more than I do. It doesn't say in detail how to set up gyro gain from the transmitter (mine is a JR X-378). What do they mean "use any spare channel providing the ATV can be ajdusted"
How do you set the transmitter up to be either heading hold or ordinary gyro stabilisation? Any help for this beginner would save me from terminal frustration - thanks

Edd

[JontheRooster]

If your Gyro has 1 male plug & 1 femal conector (servo) Yon cannot adjust gyro from your Tx. If your Gyro has 2 male conectors & 1 female you can adjust sensativity using your Tx. I have a Hitec Tx and my rudder is chanel 4 & channel 5 is for sensativity adjustment from Tx, I dont know if Jr is the same channel, but here is what I know. On the Tx setting from 01 to 50% is in standard mode, & 51% to 100% is in Heading Hold mode.Hope it helps!!

[gpitt]

Setting up the Align HH Gyro

The Align gyro is basically the Telebee gyro badged under the Align brand. It is a dual rate gyro in that it supports ordinary gyro stabilisation as well as heading hold mode.
The gyro has two methods of setting the gain, either through an adjustment pot on the gyro itself or via remote gain through plugging the gyro into your transmitters appropriate channel for adjusting gain remotely on a gyro.
If you don't have a specific function for adjusting gyro gain then any spare channel will do providing the ATV or end points can be adjusted on that channel (to set the gain).
The gyro also has two other features on it's casing, on is an LED indicating that the gyro has finished it's initialization and is now operational and lastly there is a slider switch for reversing the gyro to ensure it is giving the correct inputs, depending on how you have mounted it.

Before going any further the following things should be checked otherwise the gyro may not behave or work correctly or excessive tail wag my be present.

Blades and the head of the helicopter should ideally be balanced to eliminate any unnecessary vibration affecting the gyro.
The tail pitch slider should be able to move freely and easily with no obstructions or notchiness.
The carbon rod connected to the tail pitch slider control horn should be able to move freely and should be directly in line with the control horn. i.e. there should be no bends or flexing of the rod between the tail servo and the tail control horn.
The tail pitch slider ball links should be able to rotate freely. This means the screws holding the ball links in place need to be a little loose and not tightened down hard.
The full movement of the servo should not cause any binding at either end of the tail pitch slider travel. Make sure the appropriate **** has been selected on the servo horn. Do not try to adjust the servo movement using ATVs or end points, these should be left at 100%. On this gyro the ATV/end points just affect the pirouette speed and don't affect the length of travel of the servo.
The gyro should be mounted the correct way up, the instructions for this are in fact incorrect and if followed WILL cause a crash. The gyro should not be mounted such that it's label faces towards the sky, it should be on it's side with the label facing to either the left/right/front/rear. In my picture below the label is facing the front of the machine. In this orientation the gyro reversing switch (for me) is in the 'B' position but this may vary by transmitter.
The servo for the tail should be operating in the correct direction, more on this below.
The tail belt should be fairly loose such that it is almost possible to make the belt touch itself when pinched together
The tail rotor hub grub screw should be checked for tightness and that it was fitted with locktite. It should be possible to manually turn the tail and cause the belt to slip a notch. The hub itself should definitely not rotate independent of the belt notching round, if it does the grub screw is not tight enough and you could suffer an airborne tail failure.
Revolution mixing on your transmitter (tx) should be disabled
Any other tail mixing on your transmitter should be disabled

To check your servo is operating in the correct sense, when you command left stick the tail servo control horn should move towards the front of the helicopter.
For the benefit of beginners I should point out that when you command left stick it is the nose of the helicopter that turns to the left NOT the tail moving to the left.

Below are some pictures of the setup to help with the above description :



OK, so now we have to check the gyro is not reversed. Take the main blades off (for safety) and/or disconnect the motor. You may also want to put the motor on throttle hold (make sure before you do this that your throttle hold is set at zero throttle) just in case you knock the tx whilst performing the test.
Make sure the gyro gain is set high, 90% or so and is not in heading hold mode, again this will vary by transmitter.
You can tell when you are not in heading hold mode as the servo will stay centered, in heading hold mode the servo will creep to one extreme of it's movement.
Now with the machine on a flat surface make sure you can see the tail servo and in a short sharp movement turn the nose of the helicopter left. If the gyro is setup correctly the servo should make a corrective movement towards the tail of the helicopter, if it moves towards the nose then the gyro needs to be reversed, move the slider switch on the gyro case from it's current position to the opposite position e.g. A to B
If the servo doesn't move at all it is one of two things, either the rate is too low and you couldn't see the corrective movement as it was too small or your gyro is mounted with the label facing the sky and therefore didn't sense the movement you just made at all. Whichever it is correct and try again.

Once you have verified the gyro is not reversed it's time for a flight test.

In a previous step you worked out what gain settings to use to get normal or heading hold mode. Put the remote gain of your transmitter to around 50% sensitivity in heading hold mode. As an example on my transmitter (Hitec Eclipse 7) this is a gyro setting of 75% (0-50% is non heading hold and 50-100% is heading hold mode).

Slowly increase throttle to get the T-Rex light on it's skids and then add a little throttle to get it to just clear the ground. If the T-Rex suddenly spins and you can't stop it then your gyro is reversed and you didn't correctly set it up in a previous step. Just move the switch on the gyro case to it's opposite position e.g. B to A.

If the TRex doesn't spin or you had that but have put it right you should now be just hovering off the ground and you will either have some tail wag or you won't. You may also find you are having to hold in a certain amount of control to the tail (either left or right) to keep the tail in one place. Land and use the tail trim on your transmitter to get rid of the need to hold in tail input to keep it straight ie. if you were holding left stick to keep it straight then add left trim to alleviate this problem. Continue trimming until the model holds a relatively stable tail without any stick inputs from you.
Now we can adjust the gain.
If you have tail wag then reduce the gyro sensitivity a few points at a time until it stops. If you don't have tail wag then increase the gain until you notice the beginnings of wag then back it off a couple of points.

We now have a stable hover, you may still get wag in forward flight, if so just reduce the gain again by a few points at a time until the wag disappears.

Once you are happy that it is setup OK it's time to try non heading hold mode. Switch to this mode or adjust your gain appropriately to make the switch. Follow the same procedure above but instead of using the radio to adjust the trim of the tail adjust the tail pushrod length instead. If you need left trim then the tail pushrod needs to be lengthened, if you need right trim it needs to be shortened. Keep test flying and either lengthening or shortening the tail servo pushrod until you get to a position where you are very close to zero or only a couple of points of tail trim. Having reached this point you may find that you can now increase the gain without getting any tail wag, this is due to your mechanical set up being much better and the gyro not having to compensate for that. In non heading hold mode you should be able to get close to 100% gain, if you can't you may have a vibration throwing off the gyro. Check the head, main blades, feathering spindle, main shaft and so on to try to find the cause of the vibration.

Following this setup procedure switch back to heading hold mode and make any trim adjustments that may be necessary (as before) on your transmitter trims due to the tail pushrod length being changed. Again you may find that you can achieve a higher gain setting now that the mechanical setup is correct.

The golden rule with this gyro is that in non heading hold you make mechanical adjustments (pushrod length) in heading hold mode it is done using the transmitter trims.

If you are unable to eliminate wag then you either have an excessive vibration upsetting the gyro OR something is too tight or binding in your tail pitch movement mechanism. Disconnect the servo and feel for any binding my moving the rod manually. Double check that the ball links on the tail pitch slider can rotate freely and were connecting to the tail blade holders with the 'A' in the correct orientation as per the TRex manual. Revisit my list of things to check at the top of this page to make sure nothing has been overlooked.


This is off Trex tuning, a link within the artical. Channel 5 on Jr is the gyro switch, also used for gear. Hope this helps.