RunRyder RC
WATCH
 2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 4581 views POST REPLY
HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › gy520 not holding
06-01-2009 05:32 PM  9 years agoPost 1
darren f

rrNovice

chessington surrey england

My Posts: All  Forum  Topic

I have recently put a futaba 520 gyro in my 700 flew it yesterday and the tail kept letting go during side tictocs and backward loops.Does the gyro need to be set up in convensional mode first before changing over to hh mode.If not anyone have any ideas why this is happening.Thanks

PM  EMAIL  GALLERY  Attn:RR  Quote
06-01-2009 05:34 PM  9 years agoPost 2
Darren Lee

rrElite Veteran

Woodstock, GA

My Posts: All  Forum  Topic

Does the gyro need to be set up in convensional mode first before changing over to hh mode
No, it doesn't.

Did you have the heli set up with another gyro first or is this a fresh build? What tail servo?

PM  EMAIL  GALLERY  Attn:RR  Quote
06-01-2009 05:55 PM  9 years agoPost 3
dasd

rrVeteran

Carol Stream, IL

My Posts: All  Forum  Topic

what gain are you running?

PM  EMAIL  GALLERY  Attn:RR  Quote
06-01-2009 07:05 PM  9 years agoPost 4
darren f

rrNovice

chessington surrey england

My Posts: All  Forum  Topic

This was a new build and the tail servo is a 9256 and my gain is 70 on normal and 65 on idle 1-2 this is on a dx7.

PM  EMAIL  GALLERY  Attn:RR  Quote
06-01-2009 08:22 PM  9 years agoPost 5
Clintstone

rrVeteran

GA

My Posts: All  Forum  Topic

Aluminum case with heat sink to help cool motor
Special servo for the GY611. Compatible with Super Narrow Pulse of
(760µs) drive.

Make sure the gyro is set to (760µs). Make sure The travel limits are set properly. I am using a 14 mz and my gain is 35% in AVC mode.

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2009 02:13 AM  9 years agoPost 6
tgo

rrApprentice

HK

My Posts: All  Forum  Topic

I have the GY520 on my 450V2 with 12Z, the gain is 34% in AVCS mode, so if you are using a DX7, your gain can start with 75%.

TGO

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2009 02:58 AM  9 years agoPost 7
Darren Lee

rrElite Veteran

Woodstock, GA

My Posts: All  Forum  Topic

so if you are using a DX7, your gain can start with 75%.
That depends on how your radio is set up. If using the gear channel for gyro gain, 75% is probably way too high.

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2009 04:43 AM  9 years agoPost 8
tgo

rrApprentice

HK

My Posts: All  Forum  Topic

hi beeflyer2,
have you read the original post, darren has 65% on idle 1&2 that why I suggest 75% !

If he use gear channel, that's another story.

TGO

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2009 02:34 PM  9 years agoPost 9
AAKEE

rrApprentice

Boden, Sweden

My Posts: All  Forum  Topic

Dx7/450SEv1/HS~3000/GY520/gear channel/gain setting = 37% ATV.
Starts to tailvag at about gain 38-39.

PM  EMAIL  Attn:RR  Quote
06-02-2009 03:47 PM  9 years agoPost 10
darren f

rrNovice

chessington surrey england

My Posts: All  Forum  Topic

I am using a ar7100r receiver so the gyro gain is on aux2 so to get the gain to change with lo-hi speed it needs to be put on a mix which is aux2-aux2 on
rate:+70%
-65%
hope this makes sense

PM  EMAIL  GALLERY  Attn:RR  Quote
06-03-2009 06:30 AM  9 years agoPost 11
jtg13

rrNovice

So Cal

My Posts: All  Forum  Topic

Futaba GY520 instructions say to adjust the rudder linkage in normal gyro mode (non-heading hold) as the first step in gyro flight setup. You might want to do this since it is listed as part of the setup.

John G

PM  EMAIL  Attn:RR  Quote
06-03-2009 11:58 AM  9 years agoPost 12
Clintstone

rrVeteran

GA

My Posts: All  Forum  Topic

I agree I set mine up in normal and then it was done as the book said. I tried it without setting it mechanically so it hovered hands off in normal and then I set it so that it hovered hands off in normal and then I reset the limits and it flew great each way but I feel better with the mechanical set up.

PM  EMAIL  GALLERY  Attn:RR  Quote
06-03-2009 03:36 PM  9 years agoPost 13
darren f

rrNovice

chessington surrey england

My Posts: All  Forum  Topic

It also says in the manule that you should set it up with 0 degrees pitch on the tail but if put in normal mode like this you would have to adjust the centre any way to stop piroeting.

PM  EMAIL  GALLERY  Attn:RR  Quote
06-03-2009 10:07 PM  9 years agoPost 14
Micro-Maniac

rrElite Veteran

Pasco,Washington Formerly: Captain Chaos

My Posts: All  Forum  Topic

The manual says that if you plan to only use HH mode that you should set it up at 0° pitch at center for equal end points - But if you use rate mode or both modes then you have to offset the center position aprox. 10° - I myself usually offset the servo arm so that I have both approx. 10° offset center AND equal end points like with the 0° center HH only setup - I think manuals instruct to use 90° servo arm/linkage angles because finding the angle that gives both correct offset and equal end points may be too complicated for most people But I of course could be wrong about that - Anyway seems to work well for me

PM  EMAIL  GALLERY  Attn:RR  Quote
06-03-2009 11:36 PM  9 years agoPost 15
AAKEE

rrApprentice

Boden, Sweden

My Posts: All  Forum  Topic

manual vs IRL...
Hi!

I did the setup just about as the manual sad, zero degree pitch as I wound use the normal mode.
I did'nt notice the tail bounce for the first flights, but after I read this thread I found out the next flight that it sure had a slight bounce.

I also read about the setup with normal mode(the same setup ive used with my GY401's before) and that it might reduce the tail bounce.
so I did a new setup with the proper amount of pitch to hold the tail still in normal mode. Just checked that the tail didnt spin, then I did some tests, and as far as I can judge, the bounce became clearly smaller...almost dissapered.

If I recall it right the same 'zero setup' for AVCS mode was in the manual for the GY401. Im not sure but I think the GY401 would get some benefits if set up with the proper amount of tail pitch.

*Waiting for the USB interface to arrive, curious how the tuning will increase the performance of the GY520*

PM  EMAIL  Attn:RR  Quote
06-04-2009 01:59 AM  9 years agoPost 16
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

Hi guys.

I spent a while today talking with a Futaba Japan employee about the ideal set up of the GY520, especially in cases where guys are claiming it isn't holding as well as it should or the tail is bouncing at the end of piros.

Regardless of what the book says (remember everyone is still learning the most ideal set up of this gyro in the real world), it is now preferred to set up the tail with the model hovering at your desired head speed with neutral trim in rate mode first before switching into AVCS.

Doing it this way has always been my argued way of doing gyro set up, but with this gyro particularly, it could dramtically improve the way the gyro holds and my reduce any tendency to bounce at the end of pirouettes.

As described to me in simplistic terms for ease of explaining to others, when you force the model to fly with the tail out of mechanical trim, you're skewing a portion the internal gain the gyro uses to stabilize the tail on one side of neutral to hold against the trim error. When the trim error is significant, you can expect the gyro to not only not hold as well but also not to pirouette as consistently because the internal gain on either side of neutral is unbalanced. The degree to which this issue may be a problem in your own model will be a function of how far out of mechanical trim your model happens to be. A subtle error will create little trouble. A big trim error could undermine the performance of an otherwise very fine gyro.

FWIW,

Ben Minor

Peak Aircraft/Team Minicopter Team Futaba Team Kontronik USA

PM  EMAIL  GALLERY  Attn:RR  Quote
06-04-2009 05:34 AM  9 years agoPost 17
Clintstone

rrVeteran

GA

My Posts: All  Forum  Topic

You can also use servo speed to soften the brake or the stop crispness . In the Futaba radios it should be speed out on the rudder channel. I have been told that if your radio does not have a servo speed feature you can program this feature with a PC and the cable.

I am using a 12FG and a 14mz. By adjusting the servo speed on out you can change the way the radio talks to the gyro and it does not effect how the gyro functions but it does change the way it tells the gyro to stop the tail from pirouetting.

I tried the 9650 and went with the 9257 and the tail bouncing went away on my 500 trex with no special programing. I feel I could have gotten the 9650 to work had I spent time on it but the 9257 was easy.

PM  EMAIL  GALLERY  Attn:RR  Quote
06-04-2009 06:07 AM  9 years agoPost 18
tgo

rrApprentice

HK

My Posts: All  Forum  Topic

Hi Clintstone,

Servo speed won't work in a Gyro + tail system, remember, your rudder stick is use to control the piro speed only ! not direct control the rudder servo movement.

The servo speed function in 12/14 system just works like you add some expo to smooth out the rudder stick only.

TGO

PM  EMAIL  GALLERY  Attn:RR  Quote
06-04-2009 08:06 AM  9 years agoPost 19
jtg13

rrNovice

So Cal

My Posts: All  Forum  Topic

I might have an early manual that came with my GY520, but there is no mention anywhere in the manual for setting neutral at 0deg. The only linkage adjustment states to set for neutral in a hover, which would certainly not be 0deg. Maybe there is a newer manual since I have one of the first 520's out. My manual has a part # of 1M23N21902 on the front cover. Does anyone have a different part #?

An interesting problem though is a model like the TRex 500 that has 0deg at center pitch slider. Setting neutral in a hover will provide more left deflection than right since a 0deg center will actually be around 8deg of left input. I'm not sure what the best answer is for this, but like Dr.Ben I have always thought neutral in a hover would be the best mechanical center for the pitch slider since that would provide for equal L/R piro rates. Feel free to chime in with opinions on this.

John G

PM  EMAIL  Attn:RR  Quote
06-04-2009 12:59 PM  9 years agoPost 20
Micro-Maniac

rrElite Veteran

Pasco,Washington Formerly: Captain Chaos

My Posts: All  Forum  Topic

I found where I saw 0° center in the manual

Page 27
http://manuals.hobbico.com/fut/futm0810-manual.pdf
When using AVCS mode the optimum setup is to
have 0° of pitch with the tail rotor servo centered and use all of
the available pitch range available in the tail without binding.
If you are going to fly AVCS Heading Hold mode exclusively,
then the gyro setup is now complete.
Then page 30 it tells about setting up with 10° offset for normal mode

But as I said in my other post I usually read through a manual then ignore it and do my own thing - I like the offset setup so I can neutralize the tail at the flip of a switch and I also like to think equal end points offer equal resolution and better performance so I setup for both by offsetting the servo arm some

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 4581 views POST REPLY
HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › gy520 not holding
 Print TOPIC  Make Suggestion 

 6  Topic Subscribe

Tuesday, August 21 - 2:47 pm - Copyright © 2000-2018 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online