How to Optimize the Programming of a Telebee Gyro
WARNING: This has been tried on a sample of one, and appears to work without any problems. The only reason I even attempted this was because I seem to remember a forum topic on this at one time. Just be aware that your are messing with the brains of the gyro, so there is an opportunity that something could go awry.
There are a number of gyro parameters that you can reprogram on your Telebee gyro if you can buy or borrow the PC software and cable for programming the CSM ICG360 gyro. There is no reason why this should work, except that there must be quite a bit of similarity between the two designs (that is, almost identical).
The recessed 3 pin connector on the side of the gyro is the data input port. A same sex adapter cable is needed to connect the CSM cable to the gyro (one of the cables supplied with the Telebee works fine).
1) Do not connect the gyro to the computer initally.
2) Start the CSM PC Interface software.
3) Select the LPT port.
4) Select the RC system (JR or Futaba, and type).
5) With the transmitter off, turn on the receiver and the gyro.
6) The gyro LED should flash.
7) Plug the interface cable into the gyro.
8) Press any key on computer to initiate communication.
9) Select Flight Mode 0 (conventional) or Flight Mode 1 (heading hold).
10) The table will display your default settings in the Telebee.
11) Change settings and enter. Repeat for other Flight Mode if desired.
12) Unplug interface cable. The changes will be active on next normal power-up.
The following parameters can be adjusted for both conventional and heading hold modes:
| PARAMETER | COMMENTS |
| Conventional Gain | Sets amount of tail rotor correction as function of angular velocity; dampens like tail in viscous fluid |
| Direct Coupling | Determines how much pilot input can override gyro gain. |
| Servo Speed | Just what it says, but numbers may not be accurate. Try different values. |
| Heading Lock Gain | Sets amount of tail correction as function of angular position; acts like a spring return to position |
| Max Yaw Acceleration | Optimizes gyro to actual rotational mass of helicopter. |
| Heading Lock Range | Number of degrees over which heading will attempt to hold before breaking lock |
| Servo Travel Limit | Sets maximum throws for tail rotor servo to prevent binding. End points cannot be independently set. |
The options for both flight modes are the same. In Flight Mode 0 (conventional), heading hold gain is set to 0%, and heading lock range is not defined. In Flight Mode 1 (heading hold), some degree of heading hold gain is added, along with the heading lock range.
The gyro ATV range set on your transmitter still controls both gains remotely as you would expect. Programming the gyro can be considered another way of setting the gain. The fact that the conventional gain default for my gyro was at 60% might be the reason that the Telebees seem to want to run at higher gains than other gyros (since 60% is a relatively low gain that must be compensated by using higher ATV).
The real benefit of getting into the software is the ability to adjust the relative proportion of conventional and heading lock gains in the heading hold mode. Using only heading hold gain without any (or low) conventional gain can make the tail wag like it's on a spring, stopping only if the gain is severely reduced to the point that the gyro is no longer effective. The relative relationship of the heading lock and conventional gains is what matters. The transmitter ATV then sets the combination gain, although the proportion of the two different gains stays constant.
For example, my ECO helicopter had a wagging problem in heading hold, but not in conventional mode. I kept reducing the heading hold gain (to 50%) and increasing the conventional gain (to 125%, for damping) to get a satisfactory proportion that would provide a solid heading lock with no wagging. The transmitter ATV ultimately sets the amount of combined gain, but the proportion is always 125/50. I could theoretically get the same results with different gain settings, say 63/25 (same proportion) and a higher transmitter ATV on the gyro channel.
The other obviously useful setting is the servo travel limit. This allows the use of a long tail rotor servo arm to effectively speed up the servo response. The limit can then be reduced to prevent binding of the tail linkage. You will need to adjust your linkage mechanically to center the servo travel with the center of the total tail rotor pitch range, since the travel limit in the gyro cannot accommodate asymmetric throws.