JR 3000 gyro and 388 radio

JR 3000 gyro and 388 radio

Post by Peter Christ » Wed, 25 Nov 1998 04:00:00



Quote:

>Does anyone have experience setting up the dual rate gain on the radio
>with the 3000 gyro?
>How do you set the gain if you are using the gear channel and the
>travel adjustments are set to one positve and one negative servo
>position value?

Use the sub-trim function to move the "neutral" position of the gear channel
to a point between the two gain settings you are likely to want to use. This
should enable you to set the two gain positions in a fairly normal way. With
a 3000/2700G combination it is not unusual to be able to run 90-100% gain in
high gain. Occasionally this will give a slight sideways "vibration" on the
tail, in which case back it off a bit. Low gain will typically be about
50-60%. If you use the sub-trim to move the neutral point to about 75%, you
should then be able to adjust both high and low gain ends.

Quote:
>The 3000 manual says you need to set the tail trav adjust to 150% ,
>however when I did this the tail was super twitchy and I had to put in
>100% exponential and turn the dual rate down to 30%!!!

Run the highest gain you can get without oscillation, and then use the
travel adjust to get the desired rate of turn. 30% expo is a good starting
point, with 125% travel adjust. You probably weren't running enough gain.
The 3000/2700 will run VERY high gain without instability, giving a very
"locked" tail.

Quote:
>Any ideas why this is happening??
>Could the gyro be faulty??

I think its just your setup - its very unlikely to be a fault. As I've
indicated, the setup for a 3000 is a bit different from most other gyros,
due to it's ability to run extraordinary high gain. This in turn leads to
the need for plenty of Tx input to overide the gyro!

Pete

 
 
 

JR 3000 gyro and 388 radio

Post by Andy » Thu, 26 Nov 1998 04:00:00


Does anyone have experience setting up the dual rate gain on the radio
with the 3000 gyro?
How do you set the gain if you are using the gear channel and the
travel adjustments are set to one positve and one negative servo
position value?

Is there a better way to segt it up?

The 3000 manual says you need to set the tail trav adjust to 150% ,
however when I did this the tail was super twitchy and I had to put in
100% exponential and turn the dual rate down to 30%!!!
Any ideas why this is happening??
Could the gyro be faulty??

Any help would be appreciated.
Regards
Andrew

 
 
 

JR 3000 gyro and 388 radio

Post by Andy » Thu, 26 Nov 1998 04:00:00


Quote:

>>Does anyone have experience setting up the dual rate gain on the radio
>>with the 3000 gyro?

Thanks Pete for your help.
I ended up sending the gyro to JR Australia anyhow as when I was
adjusting the end point on the amplifier the servo was swapping
directions when you bumped the amp   ???  So it is definately faulty
however I think this had nothing to do with my setup problems

Where have you set up the gyro yourself?? (On the gear switch etc..)
If it's on the gear channel I have to adjust the sub trim on that
channel no???
WHat values have you put in your radio at the gear sub trim and travel
adjusts or you rates of gain?
I realise they will probably be slightly different on my machine but I
would appreciate a rough guide
regards
Andrew

 
 
 

JR 3000 gyro and 388 radio

Post by Peter Christ » Thu, 26 Nov 1998 04:00:00


Hi, Andy.
                I've just been swapping radios, having traded in my old 388,
and inherited my son's old PCM10! I'm actually using a 1000, though the
setup is broadly the same as a 3000. My son uses 3000s in his contest
machines.

On the 1000 in an Eagle gas, I 'm using 95% at the high gain end, and 75% at
the low gain end (this is in the PCM 10). The rudder travel adjust is set to
150% at both ends, and the expo is 30%.

To achieve the same effect on a 388, you would have to set the sub-trim on
the gyro gain channel (retracts?) to, say, 80% - then set the high end gain
to about 95%, and the low gain to about 10%. The 388 measures from the
sub-trim position ("neutral"), whereas the pcm 10 measures from the "low"
end.

On my son's contest Eagle with the 3000, he uses 95% hi gain, 65% lo gain,
25% expo for hovering and 40-60% for aerobatics. Travel adjust is 150% each
way. (this is on a PCM 10X)

Again, this would translate to a subtrim setting of approximately 80% on the
gain channel, a hi gain of about 85-90%, and a low gain of about 20-25% on a
388. (I'm working these numbers out in my head as I write, so PLEASE don't
take my translations as gospel! They SHOULD get you in the ball park!)

Hope this is of some help!

Pete