601 gyro, tempest problem

[budokan]

Hi. I just finished my tempest fai, ys 91 engine, hatori pipe, 9252 servos, pcm receiver, no governor, 601 gyro, 690 saab.
After 10+ flights, 15% nitro, we haven`t been able to have a stable (heading hold) hover. Every 2/3 seconds, the tail has a some swapping, about 1 second duration and 20/30 degrees wide.
We have change sensitivity at gyro and on the tx and the problem continue.
At the end, we also change the 601 gyro for another one, but the problem is still there.
We ask national champion, Mr. Zigras for a mechanical chek up and everything seems perfect.

Thank you, Marcelo

[Russ McC]

Hi Marcelo,

Did Zigras fly it and confirm that the engine was running correctly? I have seen YS 80 and 91s that would not run to great on less then 20% nitro. Also check that the tail grip thrust bearings are installed correctly, smaller I.D. race closer to the nut. Tie the Sensor down tight with a Velcro strap, and check to see that the sensor tape is not torn or loose. If this checks out then try another servo, the 9251 has been known to do its own thing when it’s on its way out, I suppose your servo is new but you never know. Beyond this it would be likely impossible to diagnose without inspecting it in person.

[budokan]

Hi Russ.
Yes Zigras flew it and said engine looked ok.
We change to 30 nitro and had the same problem.
I will recheck the tail bearings,
I am using nmh 3700, 5 pack batt with regulator. Some one told me that 601 don`t work ok with nmh... Do you know something in this matter?
I will try with nc 4 batt anyway, just in case... and let you know.
Thank you,

Marcelo

[Russ McC]

Don’t know what nmh would have to do with it. Your regulated voltage should be 5.1v. What is yours?

[DavidH]

I am using nmh 3700, 5 pack batt with regulator. Some one told me that 601 don`t work ok with nmh... Do you know something in this matter?

The GY 601 does not know what type of battery is powering it. With the GY 601 I have used nicad, nimh, and now Li-ion batteries.

Now if that is a 2700 nimh pack instead of a 3700 nimh pack, that may be your problem. The 2700 A cell size packs can not deliver enough power when the current demand is high. I used the 2700 mah nimh packs for about 6 months and they would send the receiver into battery failsafe on about the 3rd flight. After this happened about the 3rd or 4th time and I figured out it was the battery, I switched to Li-Ion.

David

[budokan]

Originally Posted by Russ McC

Don’t know what nmh would have to do with it. Your regulated voltage should be 5.1v. What is yours?

HI. voltage regulator, 5.2 V

[budokan]

Originally Posted by Russ McC

Hi Marcelo,

Did Zigras fly it and confirm that the engine was running correctly? I have seen YS 80 and 91s that would not run to great on less then 20% nitro. Also check that the tail grip thrust bearings are installed correctly, smaller I.D. race closer to the nut. Tie the Sensor down tight with a Velcro strap, and check to see that the sensor tape is not torn or loose. If this checks out then try another servo, the 9251 has been known to do its own thing when it’s on its way out, I suppose your servo is new but you never know. Beyond this it would be likely impossible to diagnose without inspecting it in person.

Hi. Tail bearings cheked and are ok.
Gyro and servo changed and problem continue.
Thank you.

[GJestico]

I had a similar problem with the 601 in my Latest Predator. Tail would kick 10 degrees or so at random times, no matter what orientation. I chased the auto hub, tail drive etc, even changed the engine to a YS 91 from OS 91 .
The problem ? I had mounted the 601 sensor with thin foam tap, single layer, and strapped it down with velcro just as I was told at the 3D school.
My last fix was to install the sensor with the factory Futaba supplied tape, 2 layers, with the metal plate between the layers. no velcro strap. Problem fixed, never had problem since.
Not to contradict the experts but thats what worked for me.

[budokan]

Originally Posted by GJestico

I had a similar problem with the 601 in my Latest Predator. Tail would kick 10 degrees or so at random times, no matter what orientation. I chased the auto hub, tail drive etc, even changed the engine to a YS 91 from OS 91 .
The problem ? I had mounted the 601 sensor with thin foam tap, single layer, and strapped it down with velcro just as I was told at the 3D school.
My last fix was to install the sensor with the factory Futaba supplied tape, 2 layers, with the metal plate between the layers. no velcro strap. Problem fixed, never had problem since.
Not to contradict the experts but thats what worked for me.

Hi GJestico.
I will change the tapes. They are not the originals, and seems too thin.
I will let you know.
Thanks
Marcelo

[budokan]

Originally Posted by GJestico

I had a similar problem with the 601 in my Latest Predator. Tail would kick 10 degrees or so at random times, no matter what orientation. I chased the auto hub, tail drive etc, even changed the engine to a YS 91 from OS 91 .
The problem ? I had mounted the 601 sensor with thin foam tap, single layer, and strapped it down with velcro just as I was told at the 3D school.
My last fix was to install the sensor with the factory Futaba supplied tape, 2 layers, with the metal plate between the layers. no velcro strap. Problem fixed, never had problem since.
Not to contradict the experts but thats what worked for me.

Thank you!!!
Did the replacement of the tape and... PERFECT!!!!
6 tanks on sunday and tail holds like a rock
Thanks again,
Marcelo

[WillJames]

Excellent!!! Glad to hear you got it sorted out!! Great advice GJestico!!