CGY 750 crazy ail drift on high RPM

[attila]

Hey Guys

I swapped my brain for a CGY 750 1.4 since I was not able to get the GOV working right with the brain. I have the CGY 750 as well on a rex 700n and it works really good.

Now I did my first flight today with CGY 750 on the n5c TT and it is working fine in idle up 1 and 2. Engine is YS60sr. when i switch to my idle up 3, the machine gets a hard left ail input as if it wants to tip over and i struggle to keep it up in the air. I do have to switch quickly down to a lower rpm idle up then. when the rpm drops, the drift is gone after one or two seconds. 

my rpm is supposed to be 1600, 1900 and idle up 3 was set to 2500. I think I forgot to lower that after setup up. anyways it is strange. I lowered the idle up 3 rpm to 2300 and still had the drift.
richening the engine (high needle) is lowering the rpm and helps with the drift, but power is insufficient.

I thought it might be the gain and lowered ail and ele gains from 50 down to 40 and it was noticeably less ail drift but still unflyable and definitely not crisp enough anymore down on 40.

I am afraid uf raising the gain right now up to 60 or so....

Could it be a vibration issue when I run the motor to lean which then would provoke such an ail drift?

Any other ideas?

thanks for help,
Attila

[Rodney Kirstine]

If it rolling to one side, it's definitely a vibration issue.  2300 rpm is pretty high.  I'm not sure I've seen anyone run that high, even with a YS60.

[attila]

Thanks Rodney! I have used the soft foam pad which came along with the cgy 750. It is really soft and the sensor seems to bounce on it. On my Rex I have used a much harder tape, whis damps, but does not allow the unit to bounce on the tape.

What Kind of a tape are you guys using to Mount the sensor on a nitro machine?

regards,
Attila

[Mark Burberry]

Attila,

3M VHB grey tape is excellent for hard sensor mounting.

Mark


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[Mark Dean]

+1 on the 3M tape.

I've been using it successfully on all my CGY750 installations.


Mark

[Rodney Kirstine]

Yep yep, the 3M 4011 stuff is what I use, too.

[Chris "CSpaced" Mulcahy]

Hey Guys

I swapped my brain for a CGY 750 1.4 since I was not able to get the GOV working right with the brain. I have the CGY 750 as well on a rex 700n and it works really good.

Now I did my first flight today with CGY 750 on the n5c TT and it is working fine in idle up 1 and 2. Engine is YS60sr. when i switch to my idle up 3, the machine gets a hard left ail input as if it wants to tip over and i struggle to keep it up in the air. I do have to switch quickly down to a lower rpm idle up then. when the rpm drops, the drift is gone after one or two seconds. 

my rpm is supposed to be 1600, 1900 and idle up 3 was set to 2500. I think I forgot to lower that after setup up. anyways it is strange. I lowered the idle up 3 rpm to 2300 and still had the drift.
richening the engine (high needle) is lowering the rpm and helps with the drift, but power is insufficient.

I thought it might be the gain and lowered ail and ele gains from 50 down to 40 and it was noticeably less ail drift but still unflyable and definitely not crisp enough anymore down on 40.

I am afraid uf raising the gain right now up to 60 or so....

Could it be a vibration issue when I run the motor to lean which then would provoke such an ail drift?

Any other ideas?

thanks for help,
Attila

Turn your governor off, set up a normal throttle curve and a v curve for idle up.

Troubleshoot your gyro. After you switched gyros did you mechanically set everything up again? Did you do a trim flight per the manual? Is your tail pitch slider smooth?

Once you have your tail dialed in, turn on your governor and dial in your governor gain. I run my N5c at 2250 with a Rossi .57H.

[Mark Dean]

Your head speeds are extremely high. If you are running the stock gearing of 8.5:1 you are way out of your engine power band and this is probably causing bad vibrations. The soft gyro tape is just picking them up a little better and causing the drift. That engine max rpm is 18000. A head speed of 2100 should be your highest.

Mark


Sent from my iPhone using Tapatalk

[attila]

ok thanx guys. i will switch tob3m tape as soon as rain has stoped. if 2100 is max anyways, i actually should be fine.

i let you know how things are after i made those changes.

[attila]

Hey Everyone! Good news here, the 3m Tape solved my issues with the drift. For the sake of it I tested the machine still with the head spead of 2300 set on my transmitter and: No drift at all! I then lowered the headspeed to 2100 as many of you sugested and it's a joy to fly that thing.

That original foam tape is quite unusable i'd say. 

Thank you all for your time and heli. I appreciate it a lot!

Attila

[Ross Lawton]

Good to hear Attila, the CGY750 is one of my favorite flybarless units as it feels very natural and is very easy to setup and tune with the V1.4 firmware.

Enjoy that N5C and CGY750, it's am awesome combo! 

Cheers,
Ross

[Mike Spano]

good deal

[Mark Burberry]

Glad your issue was resolved, Attila.

Mark