Guys,

In my RDS8000 the gyro gain goes from -150 to +150. Is this common on all brand transmitters?

So when someone says set the gyro gain to 60%, then should I set it to 60 % or ((150 *60)/100)%

Different brands do the gain differently.  You should ask what radio did he take the 60% from, and "translate" it to yours. 

Of course, gain depends on a lot of factors, so someone else's numbers can at best be a guideline, you have will have fine tune it for yourself.

Can you tell me how its on your futaba?

Futaba has mapped the -100 to 0 as  "0 to 100 NORM" (rate mode) and 0 to 100 as "0 to 100 AVC" (heading hold) for the gain settings for gyros that support heading hold is better specified as "GY" (as compared to "STD") when you enable the gyro function.

For example, when I do physical setup on a heli in rate mode, I enable the Gyro into "GY" mode (for heading hold capable gyros), then put the gain at "NORM 55" or so.  Then fly it and adjust the linkage until the tail does not kick even when I do sudden stops or punch outs.  After the physical stuff is ready, I change the gain to "AVC 37" or so (still in "GY" mode), and fly it, gradually increasing the gain until the tail wags, then back down couple of points on the "AVC" gain number.

The STD mode is more like your 0 to 50 (normal) and 51 to 100 (HH) setup, and can be used for heading hold gyros also, but it is generally easier to deal with the GY mode because there are no negatives or 0.5 increments to deal with or the cut off from rate to HH at 50.

OK, thanks for the detailed reply, I have only -150 to +150. -150 to 0 is rate and 0 to +150 is HH.

Right.  Futaba, using the "GY" mode,  tried to avoid the confusion that can arise from the fact that to "increase" gain in rate mode, one has to put in a "larger negative" number OR to avoid the confusion form the fact that less than 50 is rate and greater than 50 is HH.

In STD mode on Futaba, the values are like how you would do in a JR transmitter (if I remember correct). I am not sure how the extra 50% (150 instead of 100) in Airtronics works, I would assume the total range of 100 positions (0.5 increments on a 0-50 system is 100 values in total) is spread across the 150 values.