CSM400 Gyro How-to
Using the JR 662

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  Connect the 'Rud In' plug on the gyro to channel 4 on the receiver. Next run the 'Servo' wire to the plug of the rudder servo. Next run the 'Gain' wire to channel 5 on the receiver.
  Mount the Gyro on the back plate behind the main shaft. Use the mounting tape that comes with the gyro. Apply one strip on the left and one on the right of the bottom of the gyro. Make sure you clean both mounting surfaces so the tape sticks good.
  Before we continue it helps to understand the characteristics of heading hold gyros. They all have to initailize. This one takes about 5 seconds. Don't move the helicopter during the first 5 seconds after you turn it on.
Common misconception of all heading hold gyros Another thing that a lot of people don't understand is that the rudder travel adjust (TRV ADJ) does not adjust how far the servo moves. You cannot use this to prevent linkage binding. This adjustment only effects how fast the tail moves (your pirouette rate).
radio setup Disconnect the rudder link from the servo. Turn on the radio and receiver. Wait 5 seconds for the gyro to initialize.
zero revolution mixing Go to 'MIX RVH' and set it to zero. Now go to 'MIX RVD' and also set it to zero.
zero center position In the radio, go to 'SB-TRIM' and select 'RUD' and set to zero. Next use the digital rudder trim to set the value to zero.
set limits to 90% Go to 'TRV ADJ' and select 'RUD'. Move the rudder stick left and set to 90%. Do the same for the right side.
set gyro ch. Go to the System menu then go to 'GER' and set to 'A'
set the gain Go to 'TRV ADJ' and select 'GER' then set it to75%. Flip the aileron d/r switch and set that side to75% also (one of these values will be positive and the other will be negative).
set to normal mode Move the rudder stick to the right, then back to center, if the servo does the same then you are in normal mode. If the servo moves to one direction but does not move back to center then you are in heading hold mode. If your switches are in the right place for normal mode, but the gyro is in heading hold then you can go to the channel reversing menu and change the direction of the channel you use for gyro gain (REV-NORM channel 'GER').
servo direction Check the servo direction. Move the rudder stick to the right and watch the servo arm. It should move the servo clockwise which thereby should pull the rudder control link forward. This will make the nose of the helicopter rotate to the right. If not, then go to the channel reverse menu 'REV-NORM' on your radio and change the direction of the rudder 'RUD'.
With the rudder link disconnected from the servo. The first thing to do is make the link slide as free as possible. Adjust the guides to acheive the least resistance. I added a slight bent to the front section of the rod as you can see if you click on the photo to the left. I did this so as to stop the resistance the rod had on the first frame guide due to being pulled down to the servo. I also used a JR Ball link resizing tool to remove unecessary resistance from the ball links. Once you get the link as free from resistance as you can, turn on the radio and receiver. Wait 5 seconds for the gyro to initialize. Set the rudder servo arm so that it points straight up with the rudder stick and rudder trim centered. The best position for tail centering is to adjust the rudder link so that you have 4.5mm between the pitch slider and the tail rotor casing with the collective stick centered up/down and left/right. Check that the front link is centered with the servo arm. If it's not, turn the link clockwise to move it toward the back or counter clockwise to move it forward. Once the center of the ball link matches with the center of the arm and you have the 4.5mm at the tail slider, then you can move to the next step.
  Hold the tail rotor stick full right and pull the control rod all the way forward. Hold the link over the servo arm to see which hole it will align with and install the ball in that hole. You want to use the one that is furthest from center that does not allow the servo to mechanically bind. After you mount the ball, confirm that it does not try to pull the link further than it can mechanically go either right or left. Now you can snap the link on the ball.
Notes about this setup To switch between heading hold and non, use the Aileron D/R switch at the top/front/right.
CSM400 auto setup mode With the helicopter off, turn it on and before the gyro initializes, toggle the Aileron D/R switch a couple of times. The gyro will verify setup mode by moving the rudder servo back and forth a couple of times before going to center. During this time make sure the rudder trim is centered and you do not move the rudder stick. They gyro is remembering center position at this point. Now to set the gyro reversing you first check that the yellow "REV" LED turns on and off as you move the rudder stick full left and full right. Now move the rudder stick to the left and release it back to the middle. This will set the gyro direction. Toggle the aileron d/r switch to move to the next step. The gyro will 'zip' the servo back and forth in acknowledgement and again park the servo in the middle. The next step is to set the travel limits. After you just got through toggling the aileron d/r switch you should have noticed the rudder servo moved all the way to the first travel limit. Use the rudder stick to adjust this position. Toggle the aileron d/r switch and now set the other side of the travel limit the same way. Toggle the switch again and you should see the rudder servo move back and forth twice then go to center. The auto setup is now complete. For the setup changes to take effect you have to turn the helicopter off then back on.
Symptom Cause
Gain values for Normal and HH are low. 1. The helicopter is out of balance. Vibration is the cause of low gain settings. Check the blades, check for bent main shaft, spindle shaft, tail shaft, out of balance tail blades, etc.
2. I found that a sticky clutch caused me to have to turn down my gain by 20%. Check the
engine/start shaft alignment and look for a broke shoe.
3. The electronic boards inside the sensor box could be vibrating. Use small rubber foam pieces inside to cushion the circuit boards.
4. The ball on the rudder servo is too far away from the center.
HH doesn't hold good 1. The RPM's should be 1850 to 1950 for 3D flight. It's also important that your engine is running good. If your engine loads up a lot then you won't be able to keep a consistent RPM. Remember that a few hundred rpm drop on the head is several hundred rpm drop on the tail.