Yarm6

I have a HBK2 with an ESKY heading hold gyro and I just got a shiny new DX7 transmitter. I am setting up the Tx and was trying to eliminate servo creep per Finless Bob’s gyro setup video. I am using a HS-50 tail servo if that helps. I did some searching for creep, but I didn’t really find much that pertained to this.

So my question: when I start up the bird and switch into heading hold mode, I eliminate the servo creep with sub-trim. No problems. However, when I unplug the bird and plug it back in, I notice I have to re-sub-trim (aka use a different value) the servo. I have to do this each time the battery was unplugged. I was under the impression that once I did the sub-trim, it should be set, but I guess not.

Am I doing something wrong, or is this normal with the ESKY 0704A gyro, having to re-trim the servo on each start up? I was going to try to eliminate creep with sub-trim, and then adjust the position of the servo for rate mode, but having the different sub-trims puts a damper on this. Maybe it’s just best to adjust the servo for rate mode (with 0 trim and sub-trim), and then have to fiddle with sub-trim each time. This way I can go back into rate mode with it getting messed up because of the different sub-trims.

I appreciate any help or feedback you guys have. I don’t know where I would be without this forum. Thanks again.

Dave

Druss

You should set up the servos position in rate mode as much as possible to remove creep then use sub trims. The gyro would have no effect on whether the radio keeps the sub trim setting, this sounds like a radio issue. remember you have to rebind after you've set up the radio to keep the settings.

Yarm6

Thanks Druss, I didn’t even think of re-binding. I forgot you have to do that for any major changes. Unfortunately I did try to bind it again and get the same results. I notice there is no creep in rate mode, just HH. Maybe I’m just nit picking, but I thought I could use sub trim once to get the servo from creeping, and then it would remain the same every time (i.e. same sub trim number all the time). It seems a bit time consuming to have to adjust the sub trim every time the bird is ready to fly on first initialization of every new battery.

This is what I did for setup if it helps anybody.
1. Move the position of the servo on the boom with 0 trim and sub trim in rate mode to keep the tail from drifting.
2. Adjusted the gain in rate mode so there was no wag.
3. On the bench, switched to heading hold mode, where the servo proceeded to creep at the 0 trim, 0 sub trim position.
4. I adjusted the sub trim until there was no creep.
5. Bound the Rx to the Tx
6. Re-initialized
7. Adjusted the gain so no wag and repeated the process

Then I notice when I shut down and unplug the battery and then plug in a new one, I have to re sub trim the servo to eliminate creep. I have to do this each time I swap a battery. I also noticed this with my stock ESKY Tx and thought it was just the poor Tx creeping all over the place.

Sometimes I have to use more “L” sub trim and on other batteries I have to use more “R” sub trim. It’s different every time. Would a better gyro like the Telebee not creep as much, or “creep consistently”? Am I just being overly paranoid (I am an engineer and do have some minor OCD) or is there something I’m missing in setup? Also, what’s the proper way to start up the bird (in rate mode and then switch over, or start the Tx and bird in HH mode)?

Druss and everybody else, thanks for your help and time and these forums are great.

Dave