X9503 - End Points at Gear Channel for Gyro gain

[Sveberg]

Hi,

I am trying to understand the math on how to find the proper end points for the Gear channel, when using the Gear channel for gyro gain. I have not been able to find any detailed discussions on this, so hopefully this post is of interest for others also....

In the Gyro sense meny, gain from 50-100 is Heading Hold and gain from 0-50 is Rate mode. When using end points in the gear channel, you will have Heading hold with Gear switch ON and Rate mode with Gear switch off. This means I will have values from 0-100% for Heading Hold when Gear switch is on.

I am flying with 70% gyro gain in Gyro sense menu on my AR7100 receiver (TRex 500). Now I have an AR6100 in a TRex 450 pro, meaning I have to use the Gear channel and end points for gyro gain. I want to start with about the same gain as on my 500...

In the Gyro sense menu, a gyro gain of 50% = 0% true gain. So, compared to end points, 0% true gain = 0% end point. When setting 70% gain in the Gyro sense menu, I am 20%-points above 0% true gain => 2/5 between 0% gain and 100% gain. Transferred to gear channel end points, 2/5 of 100% available end point adjustment = 40%.

So, In my mind, a 40% setting in gear channel Travel Adjust menu should equal a 70% gain in the Gyro sense menu - am I right...??

[Bob O]

There are two camps on this, one that thinks the equation is 2 to 1, and the other says 1.44 to 1. I'm in the first camp as 2 to 1 makes the most sense, ie: your example of 40% in endpoints equals 70% gain. I've never been able to understand the 1.44 idea.

With that said, I've set up two helis for friends using endpoints for gain. One was a B400 with HG-5000 gyro, the other a T-Rex 450 with the same gyro. I used the 2 to 1 conversion to set gains as high as 90% (80 in endpoints). With the HG-5000, there are lights that correspond to gain ranges (not extremely accurate but gives a visual idea) and the 2 to 1 conversion corresponded to the position of the lights.

But the bottom line should be how the tail performs, not exactly the number you end up at. Regardless of the number, increase the endpoints until you get wag then back it off until it's gone. Whatever number you end up with is where you end up.

I guess a good way to compare would be if you could use both Gyro Sense AND endpoints on the same heli. Like make adjustments in Gyro sense until you get to a certain performance level. The change to endpoints and set it for the same performance level and see what number you end up with.

Good luck!!!

[Pinecone]

Originally Posted by Bob O

But the bottom line should be how the tail performs, not exactly the number you end up at. Regardless of the number, increase the endpoints until you get wag then back it off until it's gone. Whatever number you end up with is where you end up.

+1

[Rototerrier]

Originally Posted by Pinecone

+1

+2

Crank it till it wags or hunts and then back it down a bit. Done deal.

[mediclavina]

The formula I follow for a JR radio is:
End_point_value / 1.27 = True_Gain_value

So an end-point value of 32 gives 25% true gain.

[Sveberg]

Thank's for your comments.

I know that two different heli's will not perform the same with the same setting, meaning that I have to identify the proper setting for my heli. But, I am looking for an understanding of the relationship between using gyro sense settings and end point settings. That way, I can at least make a reasonable starting point for the end point settings.

According to Bob O I have got it about right...

[Pinecone]

Originally Posted by Rototerrier

+2

Crank it till it wags or hunts and then back it down a bit. Done deal.

Better is to crank it up if the tail doesn't hold. IOW, run the lowest gain that will hold the tail for YOUR flying.