Please help - I'm out of ideas :(

[jojomano]

Hi,

I've recently finished building the Synergy.
I tested a csm 560 gyro on the tail but it had small variable drifts in one direction no matter how much gain I had so I've decided to put the JR G770T + 8900G servo.

now, I have a different problem. it looks like the tail hunts in hovering and when I try to increase the gain using DX7 above 18% it wags very quickly.
with 18% gain I get the tail to lock in one direction but its hunting and not stays in the same place, like there is some vibration somewhere...(18% seems a bit low?!?)
its weird since I didn't have this vibration when I used the csm 560 gyro.

I've tried puting more pads benith the new gyro and it didn't help.
my next assumption is that maybe putting the gyro in front (under the canopy) was not a good idea and I should put it on the special mount it has.

Any thoughts? this is very weird as everything mechanically looks to be built right and I've dialed gauged everything as recommended.

please help.
Thanks.

[Chuckie]

Try 95mm tail blades.

Charles

[q8hobbytime]

how smoth is your tail?
it seems that the thrust bearings are looking up.
remove you tail grip and make sure that the iner diameter is around 10mm if no resize it or get the new thrust bearing

[Chuckie]

You can also check to make sure the first race (large outer and inner dia) of the thrust bearing is fully seated in the grip. Use a socket tool against the first end and push it into place. You might hear it snap into place. The point q8hobbytime is talking about is with the second race (the outer race) should be 9.8mm not 10mm on the outer edge.

Charles

[jojomano]

hey guys, thanks for that, I've checked and everything seems correct as you said. I wonder why this behaviour didn't happen with the CSM560 gyro?

[Chuckie]

A rough running engine might also cause drifting. How smooth is the motor running? What motor do you have?

Charles

[jojomano]

I got an OS91 SZH and it sounds very smooth.

[DavidH]

I got an OS91 SZH and it sounds very smooth.


Did you dial indicate the fan and make sure it is running less than .002?
A fan hub not running true will deal fits to the gyro.

David

[jrsandiego]

If the ship and tail rotor system is sound....Here are a couple things you can try.....Use only 1 layer of gyro mounting tape (3M grey stuff).....Adjust the travel adjustment pot on the gyro to max....Use the shortest servo arm possible but still have full mechanical travel......Set the Travel Adjustment for the Rudder to 150%....Use the Dual Rates/ Expo on the rudder....I would start at 40% expo....80% on Dual Rates.....Then adjust to your liking........Start your gain at about 21% then dial it up till it starts hunting then back it off 2-3%......Let me know if this helps...Dickson

[jojomano]

ok, here's an update, after rebuilding the whole tail (yes, including the TT), and mounting the Gyro at the back on the special gyro mount - I suspect I know what the problem was. when I've started the electronics, I found the Gyro HH mode is not setting up correctly - as soon I've switched on, it moved the tail pitch to one direction, like it got some rudder input command. I've re-bind the radio and now it starting correctly (at the middle waiting for a rudder command). hopefully, that's the end of this issue - im going to test this on the weekend - I will update.

Thanks for all the help.

[jojomano]

The synergy flys!!! what an AMAZING heli!!!
I got so carried away today that I've lost two canopy screws

Thanks for all the help, it seems like it was the Gyro calibrating wrong because I didn't rebind the radio again.

anyone know where can I get some extra canopy screws ?!?

cheers

[wascheck]

Use M3x14mm instead M3x12mm that you won't have problem with the canopy screws. I lost them too and put longer screws and never lost them anymore.

[Airboss]

i got mine up and it flies great, best heli ever . first engine too lean and burnt ring, got rebuild kit and been ripping since.tomorrow starts gallon #5 been tweeking needles.

[3DBatixkid]

Did you change to 95mm tail blades? I have been trying to get a friends 600N to fly well with the 770 gyro and it has been nothing but trouble. Can you post your current setup?

Thanks

[cbdane]

Did you change to 95mm tail blades? I have been trying to get a friends 600N to fly well with the 770 gyro and it has been nothing but trouble. Can you post your current setup?

Thanks

Hey Zak! Long time. Tony was having fits with the tail on his 600N over at EBRC and we ended up disassembling the grips and found the thrust bearing washers installed in the wrong order. Put it all back together and it was solid with no hunting. You might want to take a look.

Brent (yellow 600E at EBRC)

[3DBatixkid]

Hey Brent! I havent been to EBRC in quite a while. My friend just set his 600 up with carbon pushrods instead of wire and said he got a lot of slop out of the pitch slider. We will see how it works. Will have to check the bearings as well.

Will the 770 work with 105mm tail blades on the N9?

[deltaoverride]

Oppps

[deltaoverride]

I have a Synergy N9 and i am also using a DX7 with a JR 770 gyro JR 8900G Tail servo 105mm tail blades, I ended up with a 60% gain setting on the Gyro and it hold FREAKING AWESOME!! I have had no problem with any maneuver i can throw at it. You said that you have 18% gain and that seems like you are way to high in normal mode. I always fly in head lock mode and 60% works great for me. Is there a reason that you are flying in Normal Mode?