HG3XA problem - RC Groups
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Nov 04, 2017, 02:21 PM
Retired and Lovin' it!
TPfingston's Avatar

HG3XA problem

Some time ago, I purchased an HG3XA on a whim (thought it might be interesting to play with). At the time, I didn't have a plane that I was interested in putting a gyro in so the HG3 got set aside and more or less forgotten. This summer I got a ElectroStik and thought that it would be a good plane to experiment with the gyro. I installed it as best I could according to the instructions (couldn't figure out how to set up my Aurora 9 to work with the HG3). The first flight was almost disastrous. After a series of severe abrupt climbs and dives, I managed to get the plane down with only broken landing gear. I removed the gyro and stuck it back in a parts drawer until this weekend when I thought maybe I would try again to set up the gyro and if successful at the bench, then try again in an airplane.

The setup is as follows:
Hitec Aurora 9 transmitter
Optima 7 rcvr
4 HS 422/300 servos
2300 mah Nimh power pack
HG3XA gyro

Power up the transmitter, activate RF, turn on airborne pack. Steady red LED on rcvr. Both red and blue LED's blink on the gyro at about 1 second intervals and the "throttle' servo glitches in time with the blinking LEDS(throttle servo is not connected to the gyro-direct connection to throttle output on rcvr only). No other servos will move at all.

I have attempted to set up the Aurora 9 but the instruction manual instructions do not correspond with the HG3.

Any help will be appreciated.

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Nov 06, 2017, 11:49 AM
Xpress..'s Avatar
You do not want to follow the Aurora 9 manual for setting up a gyro as it will want you to use the gyro function on the transmitter- this is not one of those types of gyros, ignore this entirely.

You need to program in a 3 position switch (any 3 position, does not matter which, whichever you are most comfortable with) into your Aurora 9 and assign it to any unused auxiliary channel. Plug one of the HG3XA's jumper wires into that channel on your receiver (so if you use channel 6 in your transmitter as being assigned to the 3 pos. switch, then you would plug the jumper into channel 6 on your receiver).

Now plug the other end of the jumper into the channel labeled "Switch" on the HG3XA. You will now have control of the gyro with your assigned 3 pos. switch. Plug your servos into the corresponding channels on the gyro, these will be labeled as "OUT" on the right side of the servo pins.

Now plug the jumpers into the channels labeled as "IN" on the right side of the servo pins. These jumpers need to be plugged into the corresponding channels on your receiver- for example, "Aileron" needs to be plugged into your AILERON channel on your receiver, "Elevator" into ELEVATOR , "Rudder" to RUDDER.

Once you have established this, you will then need to power the model up- make sure the motor is disabled somehow, either propeller removed, or motor unplugged. Set the powered up model on the runway and perform the following procedures:

-Set the tail as though the airplane were to be flying perfectly straight and level.
-Take the 3 position switch on your transmitter and cycle it back and forth for 2 times within 1 second. This need to be done at a high enough speed to tell the gyro you want to establish the neutral point. When this has been done correctly, the gyro will indicate with a rapid series of flashing lights.

This procedure is outlined on page 4 of the HG3XA instruction manual.

At this point, you are ready to check whether or not the gyro is commanding the controls in the correct direction. Flip the aircraft into Stabilized mode (blue light) and then proceed to checking the model as per the HG3XA instructions on page 6. Ensure that the control throw directions are operating in the correct direction. Do note that it takes quite a sudden movement for the gyro to react, you may not see any movement of the surface if you move the aircraft slowly.

If the gyro is commanding the control directions of the control surface in the incorrect direction then you will need to reverse the function inside of the gyros reverse menu- please do note that by reversing the control directions in your transmitter you will effectively reverse the direction that the control surface moves by your input, not by the gyros input. What you are correcting here is the direction that the gyro tells the surfaces to move, not what direction you tell the controls to move. You can find reversing information on page 7 of the HG3XA manual, it details exactly how to reverse the gyro compensation directions.

If you need any more assistance then you may find it best to give our office a call, sometimes these things are better explained over the phone with someone- please do have all of your equipment in front of you as they will be able to walk you through the gyro setup.
Dec 31, 2017, 04:44 PM
Retired and Lovin' it!
TPfingston's Avatar
I finally got around to trying to set up the new HG3. Too cold outside to do anything else.

Setting up on the bench in a Tower Hobby Electro Stik as a test bed aircraft. Xmitter is A9, rcvr is Optima 7. Wing, therefore, aileron servos not connected (takes up too much space on the bench). Rate gyros seem to be working properly. I have done the 3 position switch toggle several times. Switch changes modes as it is supposed to.

Using Sw C on the A9. Up position turns on Rate mode, center is off, down is Head hold. Problem seems to be in the head hold position. When head hold is turned on, elevator servo slowly drives to full down and rudder servo drives to full left.

Any suggestions?


PS: I plugged a spare servo into the aileron channel and I think that it is working as it is supposed to. If I move aileron stick, it will drive the servo to a position where it will stay until I move the stick again and drive the servo to a new position where it will again stay until moved again.
Last edited by TPfingston; Dec 31, 2017 at 04:54 PM.
Jan 02, 2018, 01:11 PM
Xpress..'s Avatar
You need to set the neutral position of the gyro, place the aircraft on the bench and position it as though it were flying straight and level. Next, power up the transmitter and aircraft like normal. Once the gyro has initialized, cycle the 3 position switch for the gyro back and forth 2 times within 1 second. It needs to be a rapid movement which will command the gyro to reset its neutral position. The gyro will indicate with its lights that it has accepted the command and reset the center point.

You should not have no issues with heading hold mode, but do keep in mind that heading hold mode is very unconventional and unless the aircraft is actually flying, will seem utterly useless.
Jan 02, 2018, 08:45 PM
Retired and Lovin' it!
TPfingston's Avatar
Express, for me, the whole idea of the gyro is a personal experiment. My idea for heading hold would be for takeoff and more so for landing. My assumption for heading hold was to line up the aircraft on final approach to landing with roll, pitch and yaw set for the approach, then turn on heading hold and let the gyro control roll, pitch and yaw while I control sink rate with minor adjustments of throttle. Have I made incorrect assumptions regarding the operation of heading hold?

I will try again to reset the centering of the gyro and respond here.

Jan 03, 2018, 10:47 AM
Xpress..'s Avatar
You are welcome to try it but we generally don't advise using Heading Hold mode for anything but in flight maneuvers, it's not recommended for takeoff and landing.

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