Report for JR 6000T Gyro w/SX8000G Servo - by Bob Johnston
I first heard rumours about the new gyro from JR a couple of months back, I didn't initially get too excited about it but after talking to Curtis Youngblood about it I decided I really would like to at least try it.
Some of you may know I have been sponsored by JR for some years now but have used CSM gyro for a long time, having been closely involved with the development of all the CSM gyros. Because of my sponsorship and the speedy response of MacGregors I managed to get my hands on a gyro in a short time.The 6000T is similar in design and use to the 5000T but comes complete with a special extra high frame rate servo (SX 8000G) it can't be used with any other servo and in fact the servo has a totally different plug on the end to prevent it been used other than with this gyro.
In use the most obvious differences to other HH gyro's it the totally stable tail, all other HH gyro's I have tried or seen have a tendency for the tail to constantly but randomly hunt backwards and forwards over a couple of degrees, no matter how smooth your model is you always get a tiny amount of movement but not so with the 6000T it just sits there!
The other obvious difference is the extremely fast stop and I do mean fast!
I think I am right in saying with the 5000T you selected between heading hold and normal mode separately from the actual gain setting, so it used 2 channels to do this or to put it another way, including the rudder channel the gyro took up a total of 3 channels.
(1 for the rudder, 1 for the gain and 1 to switch between HH and rate gyro mode). The 6000T uses the same basic set up but goes a little further, in that the mode switching channel also controls the amount of heading hold, let me explain a little why you would want this feature.Any gyro's heading hold action could be described as a spring, the gyro has a memory just like a spring so that if you stretch or compress that spring it will bounce back to it's original position with the operative word been "bounce", just like the spring the heading hold part of a gyro has little natural damping and once disturbed will continue to bounce backwards and forwards for a while before finally settling down to the correct position.
So a amount of conventional "damping gyro" action is mixed in with the HH action to damp it's response down, just how much of each sort of gain to have is the question, if you just want a small amount of HH action then you just need a small amount of HH gain but if you want the tail to have a really vice like grip then you want the most HH gain you can use and still have a stable tail.
(no HH gain = smooth tail, crisp stops but no HH action. Lots of HH gain = powerful HH action but less stable tail, bouncy stops)So what JR have done is allow you to adjust this ratio from the transmitter (in flight if you want to) the CSM gyro's have always allowed you to adjust this as well but via the PC interface which meant it is was never so quick and easy to adjust.
Oddly enough I found that after a lot of test flying I have actually ended up with quite a small amount of HH gain but still have a very strong lock on the tail, this low HH gain gives the fastest, crispest stops!One thing that made a direct comparison of the gyro a little difficult at first is that it it so sensitive to stick inputs, I have ended up with 65% expo on the rudder channel and it is still a little sensitive like this, this some times gives the feel that the gyro is not holding that well but this is not the case, what I was seeing was the results of me accidentally putting in very small rudder inputs.
I spent a lot of time doing extremely testing things with the tail trying different settings to look for very small differences, I found how consistently I could stop the model tail down from a "ripper" was one of the most telling tests and I managed to make several improvements to my original settings, some very small and some a little bigger, I didn't realise how much better it had got until I went back to flying another of my Millennium's which is fitted with a CSM 540 and old type 2700G servo.
I found that I had got so used to the stop of the 6000T that my timing was way out on any rapid stops and the rotation rate was no where near as consistent during stressful manoeuvres like the ripper or pirouetting loops!I do feel that where the CSM gyro's are critical on having the model set up just right, the 6000T is not so critical of model set up but the set up from the transmitter is a little more demanding so the gyro may not be for every one but if you must have the very best available then this is the gyro for you.
For the average sports 3D set up the CSM 540 coupled with a JR DS8417 servo still makes a very good package at a more affordable price.
The current instructions are I believe a direct translation from the Japanese instructions and not that clear really, I plan to write some brief additional instructions that will be posted on my website in the very near future and I believe Mark Christy is also working on some extra information, I presume JR's US distributors "Horizon" are also working on instructions, they are responsible for most of the JR manuals and these are generally very good so it is always worth checking their website for these.
So the bottom line is how much do I like it, well all I need say is all my main models will be fitted with the 6000T as soon as I get some more of them which with luck will be some time this week (first week of April)
My setting with the 6000T, PCM 10X, Millennium 2 fitted with NHP 105mm tail blades.
Heading hold amount is 20% (This is JR "travel adjust" value)
Gyro gain is 52% (This is a JR Code 44 gyro gain value)
Rudder channel "travel adjust" values are 130% left and 150% right.
I used a 20mm servo arm.
(3rd April 2002)