gy502 & ff9

[Bender]

Anyone got a good setup?, I am terminaly confused by the interaction of gain settings on the tx and the gyro amp, and dont want to fry my servo with too high a gain (it seems that with this gyro you can go too high without it showing the tell tale wagging)

[Raptorite]

Hi Bender,

All my IC models are equipped with the GY502 gyro. I find them to be very good, especially with a 9254 tail servo. I have in the past used a FF9C transmitter with mine.

The interaction of gain settings between the TX and gyro amp takes a little getting used to, it confused the hell out of me when I got my first GY502, thats for sure :?

If you are using the Gyro gain option in the FF9's menu, you will need to set the transmitter such that anything upwards of 50% is normal mode and anything downwards of 50% is AVCS mode on the gyro. This is assuming you have the mode on the gyro itself set to "CMT" which means the gyro is switchable between normal and heading hold, or AVCS as it is called on this gyro. Because you are only effectively using a % value of 1 to 50 to set 100% gain, the value shown on the TX will be multiplied by 2 to give the value you should see on the amp. For example, my AVCS mode is set on the TX as 25% gain, this translates to 50% on the amp, 26% on the TX translates as 48% on the amp, and so on.

The maximum amount of gain I like to run is around 50% in AVCS mode, this is on a Raptor with about a 13.5mm distance between the centre of the servo horn and the ball. I have run higher gains than this quite easily, but if you do so you must remember to lower the AVCS % on the amp itself, I normally run about 85% AVCS with 50% gain, this I find holds very well.

I hope this helps.

Cheers,

Pete.

[Bender]

Raptorite, thanks for the reply, so lets see if im getting this?...I aim for about 50% in hh (avcs mode) as read at the amp?..and this will work out about 25% read at the tx?
oh and yes I am using a 9254 and cmt switching

[Raptorite]

Hi Bender,

Thats it, you've got it. A couple of things to look out for, one is the distance between the centre of the servo arm and the ball seems to be best at about 13.5mm, any more and the gain will have to be lowered, meaning the gyro doesnt hold so well, and any less meaning you can increase the gain but then you have the potential of over driving and damaging the tail servo.

You should be looking for 50% gain on the amp, with the AVCS option on the amp set to around 85% and 25% gain on the TX.

The other thing I didnt mention in the previous post was the setting of the pirouette rate, this is done by setting the ATV's on channel 4 (Rudder) on the TX to 120% both ways, you might find that leaving them at 100% the pirouette rate is a little too slow. The higher the value you use the faster the pirouette rate is.

In general operation terms, always make sure the TX is set to HH mode when you power up the receiver, otherwise the gyro wont initalise properly.

Cheers,

Pete.