Where can I go to

[porsche]

Where can I go to read and fully understand gyro setups ?? John helped me set up my 500T "thank you John" but I don't fully understand the principle of the thing. I know to some of you it's easy but I am not big on this electronic stuff. I have read and reread the instructions and I just don't get it. I can read but I guess I need it spelled out a little better.. Thanx Alan

[Hotshot Charlie]

It doesn't get any better than this:

http://www.raptortechnique.com/gy401-jr8103.htm

Good luck and let me know if I can help.

[porsche]

MAN did that help thanx... Alan

[Hotshot Charlie]

Alan, I just saw you are using the 500T, sorry I sent you the info on a 401.... but I couldn't find a setup on the 500T, there is one on the 5000 on the same site.

Good luck !

[TMoore]

Here is what I would do to set this gyro up:

Use an arm with the ball out 16-18mm from the servo center. If you are using a JR radio and using the gyro function, bear in mind that 0-50% is like "minus" EPA/ATV so the gyro will be in rate mode. 50%-100% is "plus" EPA/ATV and will be in HH. Futaba uses something similar but they call it Axxx% or Nxxx%, A being AVCS mode and N being Normal or Rate mode. This makes a difference because ATX doesn't work like this. I had to use a pulse counter to check to make sure what is what with these values. 0-50% is like 0 to -125% and 50%-100% is like 0% to +125%. Scott advises to use 68%-75% gain in high rate. Here is a little trick. On the bench set the gain in HH to max (whatever your radio supports) and watch the gyro drift. Use "subtrim" or "center" to stop the drift. At this high rate there may be some drift but not always. Flip the gyro back and forth from rate mode to HH to center the servo and watch for drift, then subtrim the drift out. Make sure the gyro is in HH to watch for drift, it won't drift in rate mode. Checking for HH mode is easy, just move the stick, if the servo snaps back to center you are in rate mode, if not you are in HH mode. Make sure there is no rudder trim in the radio.

Make sure your rudder EPA/ATV is at 100% during the setup. Set the total travel on the gyro in rate mode and check for binding. No binding is the goal even if you are short on travel in one direction or another. I have another trick for that issue later. Reset your gyro gain to JR68%/FutA68% or +80 on ATX. Set the rate mode to JR25%/FutN25% or -80 on ATX. This will give you a starting point.

Once these steps are complete look at the tail blades and make sure you have the direction set correctly. Incorrect settings here will make your machine a handfull on test flights if you aren't careful. Setting the gyro sense direction is easy. Rotate the maingear in the direction of rotor rotation and watch the tail blades, make sure the tail blades are in their grips in the right direction and based on the direction of the rotation of the tail blades imagine where the air will be pushed from the tail blades when you give right tail rotor. This direction will tell you which way the body of the machine will rotate when you give right tail rotor. Now look at the servo and see which way the servo moves when you give right stick. In rate mode twist the body of the heli to the left or CCW and watch the tail servo, not the tail blades, if the tail servo moves to give right tail rotor you are set. If not, fix it. Set the rudder direction in the radio and the gyro sense on the gyro and you should be good to go.

Once all this is sorted out, look at the tail blades in rate mode and make sure that you have some pitch in them. Tail blades with no pitch will be out of trim in the hover. If you just fly in HH mode and depend on the gyro to compensate you are losing half of the effectiveness of the system. You will need to trim the heli in rate mode, mechanically by making changes to the rod length from the servo to the tail rotor. Let's say you fly the machine in rate mode and the nose is going to the left and you have to hold a lot of right rudder to keep the tail straight. At this point you may be out of adjustment on the tail pushrod or can't slide the servo along the tail boom depending on the machine you fly. Here's that trick I mentioned. Rotate the servo arm one spline in the direction you need and reset the mechanical endpoints in the gyro and you should now be able to trim the tail.

The 500T's that I have set up hold like vise grips on the tail and work very well. If you are using the 8700G on the tail the reason that JR want you to use PCM is due to the noise that the 8700G emits from the servo amp and motor. JR SC FM RX's don't like this. To be honest I haven't tested this with ATX and don't know if you could use FM or not.

TM

[porsche]

Thank you guys, my 500T is set up just fine thanx to John Garst but I just need to understand exactly what % does what but I have alot of info from here and from the sight that hotshot sent me and with all that hopefuly I can understand it, maybe reading it many times it will sink in Thanx Alan