JR G770 Gyro Setup Videos + some new 101's

[ping]

Originally Posted by SeanOC

I set up the 770/3500g as per the vids. ball at 8.5mm, 90 degree servo arm (used 4 clicks of subtrim to achieve) centered the pitch slider, adjusted pod on gyro to eliminate buzzing (apx 80% on the pod),

Make sure you rebind after adding subtrim

I tried increasing the pod to 100% despite the buzz figuring that dual rates would prevent reaching full travel and therefore servo damage.

This is very bad the gyro can drive the servo beyond what the radio endpoints are set for. You MUST set the endpoints on the pot.

I'm at a loss. I have had the problem since I first built the heli and nothing I have tried works.

This leads me to believe it is a tail mechanical or blade issue. My Trex 500 running a JR770 was VERY picky on what tail blades caused bounce back and which did not. The Align carbons ultimately proved to solve my bounce back issues.

You simply might have to gain set too high also. If the tail holds at 61 percent leave it there. Gain values will be different on every heli and gyro combo. Because someone is running one gain doesn't mean you can run the same even if your setup is identical.

[SeanOC]

Originally Posted by rupps5

have you tried to move the ball in on the servo even more?

Yes, in as far as 8mm out as far as 11mm.

Make sure you rebind after adding subtrim

One thing I havent tried will do, although I doubt that will help the bounce back problem because I have tried different servo arms including ones were 90 degrees w/o subtrim and still had the problem.

This is very bad the gyro can drive the servo beyond what the radio endpoints are set for. You MUST set the endpoints on the pot.

I only tried it for a test hover out of desperation, I don't fly like that.

This leads me to believe it is a tail mechanical or blade issue. My Trex 500 running a JR770 was VERY picky on what tail blades caused bounce back and which did not. The Align carbons ultimately proved to solve my bounce back issues.

Well I have tried it on both a belt and a torque tube, with the stock tail and the kasama tail, with and without chinese weights. I have also tried it on both Align CF and Radix tail blades. I don't know what else to try as far as the tail goes.

You simply might have to gain set too high also. If the tail holds at 61 percent leave it there. Gain values will be different on every heli and gyro combo. Because someone is running one gain doesn't mean you can run the same even if your setup is identical.

I am getting the bounce back at almost all gain settings. I set my gain as per Bob's vids and any other gyro I programmed. Slowly raising until I had a wag then backed off. 61 is my personal number, not something I copied from another setup.

I really appreciate the ideas guys, will rebind and report back. Any more ideas are much appreciated!

[SeanOC]

I just did some test flying and found that 60 was an even better number, however I am still getting a bounce back.

Interestingly when I go lower, closer to Rate mode the bounce gets worse. At 54 the bounce was very bad.

[idigrc2]

Try some zeal tape and see if that helps.Settings on my 600n with the 8900g are 61% gain with the ball 12.5mm from center using the big round wheel, 40% expo and 68% dual rate. Running align carbon blades with kasama grips and the tail is rock solid no bounce with the endpoints set bolth at 150

[Pinecone]

I forget, did you even out left/right piro rate?

And I assume, that when you changed the ball distance you reset the limit and the tweaked the gain?

[SeanOC]

Originally Posted by Pinecone

I forget, did you even out left/right piro rate?

And I assume, that when you changed the ball distance you reset the limit and the tweaked the gain?

Yes to both, however I did find that the piro rates were very close with the end points at 150/150 which according to Bob's video is unusual.

[ping]

Are you sure your hitting both endpoints on the tail pitch slider? Are you getting bounce on both directions? If your getting bounce on only one side try reducing the ATV throw for that direction.

Tape is another big one if you haven't already changed it the stock tape is horrible. Two or three layers of 3M outdoor tape and zeal tape work well with this gyro.

[SeanOC]

Originally Posted by ping

Are you sure your hitting both endpoints on the tail pitch slider? Are you getting bounce on both directions? If your getting bounce on only one side try reducing the ATV throw for that direction.

Tape is another big one if you haven't already changed it the stock tape is horrible. Two or three layers of 3M outdoor tape and zeal tape work well with this gyro.

Depending on settings I either get bounce in one direction or both. As of right now with gain at 60, 40% expo, 65% dual rates, 8.5mm, 142/150 I am getting a bounce on left (CC) piro stops.

I will try reducing the left side atv more to see if that helps, although I have brought them both down to 120 with no effect before.

As far as tape goes I have Futaba gyro tape on at the moment which is fairly thick. I have a roll of 3m outdoor I can switch back to as well. I am curious though ping.... what is bad about the stock tape? Is it too strong or too weak? Is 1 layer of 3m too strong hence the layering you suggest?
What does this gryo like a little give in the tape?

[ping]

I believe it transfers too many vibes. The best gyro tapes feel more like gel than foam. Zeal and 3M tape are the only examples I can find.

A single layer is probably not enough dampening, 2-3 layers work best from my experience.

When your testing for piro stops do you stab at the stick and let it recenter with spring tension or do you use a smooth controlled motion?

[idigrc2]

I forgot about this but take the cover off the gyro and see if the board is loose inside, there is a small dap of glue that hold the board down if the board comes loose it will cause that. Simple fix is a dap of hot glue in the corners to secure it.

[Jamesppp]

What is the reasoning behind maxing out the end points then effectivly changing them with the dual rate function?
I know it works well, I just dont really understand the theory. When I posted this method on another group as the way I had my 770 setup, some guy responded that it is a myth that this will help maintain higher resolution and then made a list of other things that he called myths about gyros.The only thing that I could offer was that I thought using this method might keep the resolution higher than lowering the endpoints directly..and that it worked

What is the deal on this?

Thanks,

Jimmy

[trebor27]

Originally Posted by Jamesppp

What is the reasoning behind maxing out the end points then effectivly changing them with the dual rate function?
I know it works well, I just dont really understand the theory. When I posted this method on another group as the way I had my 770 setup, some guy responded that it is a myth that this will help maintain higher resolution and then made a list of other things that he called myths about gyros.The only thing that I could offer was that I thought using this method might keep the resolution higher than lowering the endpoints directly..and that it worked

What is the deal on this?

Thanks,

Jimmy

Interesting question.. This exact thought has been in my head for some time now.

Radio resolution wise I don't believe there is any difference between the two methods.... The only thing the dual rate method brings to the table is the ability to have switchable rates... But you could just pick the endpoints that you want for your fastest piro speed, and then setup a dual rate to slow it more from there. I don't think there will be any difference then....

Oh.. The other thing is. Dual rates method makes it really easy to "visualise" how much of your maximum travel you have... i.e. wind your end points out to 150 each way, then a dual rate of 50% is REALLY 50%, if you have the endpoints at 75 each way then a dual rate of 50% isn't a true 50%. Not that that makes much difference, as you usually just setup for whatever piro rate you are comfortable with!

That's my impression anyway!

Oh and it makes it easier to explain with the max endpoints!!!!!

[TheBum]

The channel endpoints and dual rates have nothing to do with slider travel except as related to gyro piro rate, i.e. they tell the gyro how aggressively to move the slider to achieve the piro rate. You need to get over the idea that they directly affect slider travel.

[ping]

The issue with maxed ATV's has been brought up in at least 2 other threads and talked about in length. The reply from a JR rep was a maxed ATV curve compressed by the dual rates in the radio offers the most resolution.

[Jamesppp]

Originally Posted by ping

The issue with maxed ATV's has been brought up in at least 2 other threads and talked about in length. The reply from a JR rep was a maxed ATV curve compressed by the dual rates in the radio offers the most resolution.

That is where I got the info from. I didnt remember if it came from a JR rep or not. I believe that with the ds760 Spartan a question like this posed directly to the company would get a good answer.

If that is what happens,(compression) then I see why you do it, if like others say it doesnt offer any real advantage by improving resolution then why not set it up like I do some other gyros, using endpoints directly to get right and left piros equalized and maybe dual rates to if you want a different setting in another flight mode.??

I wonder

Jimmy

[ping]

The only one that can answer the question correctly IMO are the radio manufacturers as it's a matter of how the firmware in the radio handles everything.

JR has it in the manual for a reason.

[j bomb]

As was explained by Bob himself, at least on R/C Freak. Using the D/R to adjust piro rate offers 2 advantages:

1. You can adjust piro rates quickly w/o having to do any math, even if your L/R endpoints are different, just by changing the D/R percentage.

2. It allows you to switch between different piro rates in flight. You can do this by flipping a D/R switch or, on some radios, have the D/R linked to your flight mode.

[Finless]

Originally Posted by j bomb

As was explained by Bob himself, at least on R/C Freak. Using the D/R to adjust piro rate offers 2 advantages:

1. You can adjust piro rates quickly w/o having to do any math, even if your L/R endpoints are different, just by changing the D/R percentage.

2. It allows you to switch between different piro rates in flight. You can do this by flipping a D/R switch or, on some radios, have the D/R linked to your flight mode.

Thank you!

I tried in my videos to explain that rudder end points NO MATTER HOW they are achieved has nothing to do with slider throw and everything to do about piro rate. This is true with most EVERY gyro out there today! Spartan, Solid-G, 401, 611, 502, Hitech, etc....

If your not getting this concept then let me know HOW I can explain it better please as I would love to make sure ALL understand how this works.

Bob

[RMG2]

Originally Posted by Finless

Thank you!

I tried in my videos to explain that rudder end points NO MATTER HOW they are achieved has nothing to do with slider throw and everything to do about piro rate. This is true with most EVERY gyro out there today! Spartan, Solid-G, 401, 611, 502, Hitech, etc....

If your not getting this concept then let me know HOW I can explain it better please as I would love to make sure ALL understand how this works.

Bob

I get it Bob, and I'm a new heli guy!

[Pinecone]

Originally Posted by SeanOC

Depending on settings I either get bounce in one direction or both. As of right now with gain at 60, 40% expo, 65% dual rates, 8.5mm, 142/150 I am getting a bounce on left (CC) piro stops.

Realize 40% expo is like 0 expo on most other gyros. Try going up to 50% o rhigher expo. Your bounce may be stick overshoot when going to center, especially if you are releasing the stick to get a quick stop.