JR773D & 8900G help

[TRAMTRAN]

Anyone please offer your JR7703d & 8900G setup. Below is my setup and it’s almost killing my T rex 600 tail this weekend and the tail wag was so powerfull and I am just scare to try it again.

Specktrum DX7
ATV=150%
EXPO = 50%
D/R = 80%
GAIN=60%
13mm servos arm
Tail wag was so bad with this setup

Here are my new setup
Secktrum DX7
ATV=150%
Expo = 50%
D/R = 80%
Gain will start with 30
11mm Servos Arm
Before I start with this new setup, I would like to have your opinions.

[brgsstm]

why 150 an the atv? 80 on the d/r?

I would use 100 on the atv and 100 on the d/r. then use some expo on the tail if needed to slow it down. essentially with 150 on the atv and 80 on the d/r you are probably still getting a faster piro rate than you would get if you used 100 atv and 100 d/r.

I would also suggest that 60 on the gain is too much. try for around 40, you should then be able to lower it some more if still experiencing wag.

As for the servo arm i use a futaba servo with the 4 arm servo arm on the 3rd hole out. perfect throw in each direction. however i do not know what that is in mm. I will measure for you later when I get home.

Tom

[TRAMTRAN]

brgsstm
below setup is according the JR770 Gyro manual for T rex 600N.

JR Receiver
ATV=150%
EXPO = 50%
D/R = 80%
GAIN=70%
11mm servos arm
with above setup for Specktrum DX7, I found it's very dangerous.

[brgsstm]

I'm surprised the manual says to set it up like that. Try it with 100 atv 100 d/r and 40% gain. I think wou will be pleasantly surprised :thumbup:

Tom

[WayneBrown]

I'm surprised the manual says to set it up like that. Try it with 100 atv 100 d/r and 40% gain. I think wou will be pleasantly surprised :thumbup:

Tom

that won't work with the 7703D. You need to follow the directions, or you'll be screwed. The 770 is NOT like other gyros on the market.
Look over your linkage for binding, including the arms from the tail yoke to the tail grips.
Look as well at the pivot mount for the bellcrank, I've had two come loose and it wags a mother..
and You want 11mm for the ball on the servo, you stated 13mm at first, thats likely the issue.
Use the default settings in the manual, and tone down the piro rate to suit you.

[chosen69]

Anyone please offer your JR7703d & 8900G setup. Below is my setup and it’s almost killing my T rex 600 tail this weekend and the tail wag was so powerfull and I am just scare to try it again.

Specktrum DX7
ATV=150%
EXPO = 50%
D/R = 80%
GAIN=60%
13mm servos arm
Tail wag was so bad with this setup

Here are my new setup
Secktrum DX7
ATV=150%
Expo = 50%
D/R = 80%
Gain will start with 30
11mm Servos Arm
Before I start with this new setup, I would like to have your opinions.

If your gain is below 50% you will not be in HeadingHold mode but in Rate mode... I'm not sure you want that ? 51% equals zero gain on the gyro if you use the GYRO SENS menu on the DX7. Make sure that you have either AUTO selected and then link the RATE 0 or RATE 1 to the flightmode position unless you want it linked to the RUDER D/R switch which is probably your throttlehold so I wouldn't recommend that.

You should try the factory recommended setup first with the 11mm Arm length ! If you had 13mm before, your arm travel was probably too much and induced the tail wag.

[Bobbyk]

that won't work with the 7703D. You need to follow the directions, or you'll be screwed. The 770 is NOT like other gyros on the market.
Look over your linkage for binding, including the arms from the tail yoke to the tail grips.
Look as well at the pivot mount for the bellcrank, I've had two come loose and it wags a mother..
and You want 11mm for the ball on the servo, you stated 13mm at first, thats likely the issue.
Use the default settings in the manual, and tone down the piro rate to suit you.

As Wayne said follow the manual and you will be good, on mine I reduce the gain to 62 and end points I reduce it to 130 on DX7. If you still have wag then is something else not gyro related.

Good luck, you will love this gyro, trust me.

Robert

[brgsstm]

that won't work with the 7703D. You need to follow the directions, or you'll be screwed. The 770 is NOT like other gyros on the market.
Look over your linkage for binding, including the arms from the tail yoke to the tail grips.
Look as well at the pivot mount for the bellcrank, I've had two come loose and it wags a mother..
and You want 11mm for the ball on the servo, you stated 13mm at first, thats likely the issue.
Use the default settings in the manual, and tone down the piro rate to suit you.

sorry guys, i'll butt out,

Tom

[onemetre]

I have it on authority that the heli needs to have the rate hold setup to be complete (i.e. not move in hover without wind). Then go onto rate setup. This is also another point of deviation from other gyro's like the Solid G (which has no rate mode).

Rob

[TRAMTRAN]

Spektrum DX7
[D/R & EXP]
POS-0
RUDDER
EXP 50
D/R 80

ATV
150%
150%
I am using Gear Channel as my gain
Heading Mode = 40%
Normal Mode = 40%

Accroding to manual
Below 50% gain is normal mode and Above 50% gain is head hold mode

According to my setup heading mode = 40%, am I in heading mode or normal mode?

[captcasper7]

I have this combo in both my 600n's and my settings are as follows;

Rudd L110% R110% ATV
Gain +30% - 30% (using Gear switch)
Servo horn 11mm
D/R 100%
EXP 30%
Head speed 2100
Tail blades Radix 95mm

The gyro is rock solid

If you go much higher with the gain you start to get the wag coming out of backward loops.

[TRAMTRAN]

Thank you very much captcasper7, I got my laptop out here at the field and just open up and saw your setup, used it and it's solid rock and thank you for everyone opinions.

[fiveoboy01]

One question I have pertaining to the 770/8900 combo.

I realize the manual states to put the rudder ATV at 150% and then knock the piro rate down to what you want by using the dual rates.

My question is why do they have you do this? Let's say I've got it set at 150% and I use 50% for the dual rates. This would be the same as if I set the rudder endpoint to 75%(half of 150) right?

Do they have you max the endpoints and knock them down with the D/R for a reason? Or is it just so that you can have different piro rates in different flight modes?

If the latter is the case, I'd rather simply leave the D/R to the normal 100% and set the ATV to my desired piro rate because I would want it the same in all flight modes.

[chosen69]

Spektrum DX7
[D/R & EXP]
POS-0
RUDDER
EXP 50
D/R 80

ATV
150%
150%
I am using Gear Channel as my gain
Heading Mode = 40%
Normal Mode = 40%

Accroding to manual
Below 50% gain is normal mode and Above 50% gain is head hold mode

According to my setup heading mode = 40%, am I in heading mode or normal mode?

If you are using the gear channel (and therefore ATV settings of the gear channel) for your gyro control everything above 0 will be HH which you can find in the 770 manual under " When using Travel Adjust to change the Gain". Everything below that (from 0% to -100&) will be rate mode. So positive values are HH (also called "tail lock mode") and negative values will be rate mode.

[chosen69]

One question I have pertaining to the 770/8900 combo.

I realize the manual states to put the rudder ATV at 150% and then knock the piro rate down to what you want by using the dual rates.

My question is why do they have you do this? Let's say I've got it set at 150% and I use 50% for the dual rates. This would be the same as if I set the rudder endpoint to 75%(half of 150) right?

Do they have you max the endpoints and knock them down with the D/R for a reason? Or is it just so that you can have different piro rates in different flight modes?

If the latter is the case, I'd rather simply leave the D/R to the normal 100% and set the ATV to my desired piro rate because I would want it the same in all flight modes.

That's exactly the reason why they make you set it up that way, so you have 3 different piro rates available (with possibly full travel (piro rate) @ 150%) one for each flight mode. You need to understand that this gyro is optimized for hard 3D flying. If you are happy with just one piro rate you can set it up just like you described it above.

[mlucia]

http://www.horizonhobby.com/ProdInfo/Files/JRPG7703D_G770T_MANUAL.pdf

[R1R 7humbs]

I have our 770 approx. setup according to the JR manual. It works perfectly... it's smooth until I push the rudder to max, at that point it turns into the ultimate fly swatter. :YeaBaby:

ATV @ 150%
Gain @ 60 (it was 62 but we had minor wag after certain moves).
Expo 0%
Travel adj on the gyro its self (adj using the phillips head accepting knob on the top of the gyro): set to the absolute minimum (set this while in rate mode)

Also, according to the JR manual there are "bad values" for the gain. Make sure you don't set the gain to one of those values in your Tx. It's about a 5 point "dead zone" between rate and heading hold modes.

[simmer]

I have this combo in both my 600n's and my settings are as follows;

Rudd L110% R110% ATV
Gain +30% - 30% (using Gear switch)
Servo horn 11mm
D/R 100%
EXP 30%
Head speed 2100
Tail blades Radix 95mm

The gyro is rock solid

If you go much higher with the gain you start to get the wag coming out of backward loops.

OK what if I am set up in the gyro menu? not the gear channel? What settings change and what do they change to?

[simmer]

Ohhhh I think I get the gain settings now

from the manual,

When Using Gyro Gain Control
Gyro gain control is as shown in the figure below.
Above the gyro gain control value of 50% is the
tail lock mode, and below it is the normal mode,
with zero gain at 50% and the maximum gain at
both ends. Do not use a range between 49% and
51% because it is unstable.

So gain in HH mode is from 52% little gain to max gain at 100%
Gain in non hh mode is 48% little gain to max gain of 0%
is this correct?

[WayneBrown]

Yes, look at this as a dual 0-50 scale.
0-50 and 51-100
setup for rate would be 12%(gain) minus 50%(zero point), or 38% for rate, 62% for HH

[jaycab]

Tramtran

This is the setup I'm running on my Pantera (DX7) , JR/773D W/8900G round servo wheel.

Rudder
Exp +50
D/r 85

Travel Adjust
150 each way

Gyro sense
0: 65
1: 65

Rock solid, try it, I hope it works for you

[simmer]

cool thanks, I read and reread the manual today and I think I now fully understand it. The description changes if you setup in gyro menu or gear channel, and the dual rate is to tone down the atv and is where you adjust the piro rate for the three flight modes. I now GET the dual rate function in the gyro menu. The manual is a little confusing but I do get it now.

I did not see that is tells you you MUST set it up in rate mode first before you go to hh mode, but that sort of makes sense anyway (adjusting the linkage to get it with no drift in rate mode. I am resetting up the tx now, will have to check and set the 11MM on the servo horn. I'll follow the guidlines for the 600N in the manual

I did see there are two manuals? maybe an older one and a newer one?
a JGG 770T (must be the older one and a JR G7703D The manuals appear to be the same.

[G MAN]

I used one of the align servo wheels for the TR,it's the right size for the 770.You dont have to set t up in rate mode,it serves no purpose.I set mine up in HH mode and adjusted the pushrod for no drift.

[simmer]

Yea I think Ill get another set of those, the JR wheel I use currently I checked last night. Its 12mm and I am shooting for 11. Small difference but it could have an adverse effect.
Ill probably try to find something that gets me to 11 until I can get some more of those align wheels.

As for setting un in rate mode. I virtually NEVER fly in rate mode, I only use it after I have initialized to prevent the tail from pegging while I walk to the flight line.

[WayneBrown]

1mm is not a drastic enough difference to matter in this case.
All that is required is to lower your gain by 1-2% to get the same result.