450 Rate and HH gains

[Eggy 71]

I'm a little confused with regards to rate and heading hold. I've got a 450 L dominator with a 3GX that seems to be handling quite well. I built it from scratch and have a dx6i for a tx. In setting up the gains I find it handles best around 65% gain in either normal with a gradual pitch and throttle increase or in stunt with a linear pitch and slight v curve. In reality it will only fly in HH mode. If I try to set a rate mode the heli wants to spin clockwise during startup.
I guess my question is have I done / missed something in setting it up that won't allow a rate mode or what's the point of the two modes?

 

[murankar]

heading hold is used to hold the bearing of direction while fighting forces. Rates ares different, rates or dual rates will limit the 100% of travel.

what does this mean? If your servo travel is set for 100% with 0% dual rates then you get full travel of the servo. Now if you keep the 100% travel and need less travel on one setting then more on another then dual rates get set. for one setting you may set 70% and 90% on the other. this means that on the first setting you will get 70% of the original 100% of travel. the second setting you'll get 90% of the full travel.

Head hold will fight to keep the direction of the last input. If you point the nose north and if the wind blows the nose east then head hold will fight to keep the nose north.

 

[Eggy 71]

Thanks for the input. I think we might be talking about two different things. It's not the dual rate that is confusing me, it's the rate mode of the gyro. From doing a little research it seems almost no one ever even sets up rate mode anymore. The gyro has the ability, shown with a green light, but I can't set up the heli to be stable enough to even keep a steady hover, no matter what I set the gain to in rate mode. In my dual rates both have the gyro in HH mode in order to keep the heli stable.

 

[Tony]

The green status light on the gyro means it's in HH (Heading Hold) mode. A red status light would mean it's in Rate mode. Always fly in HH mode, always. Rate mode is dead and the only reason I put it in my Tx is to center my blades for I take off.

On the 3GX, it's going to depend on your setup as to how you actually program HH mode. Since you are using a DX6i, I hope you are using a separate receiver, and not just a satellite. You can not use just a satellite with a 6 channel Tx because using only a satellite puts the gyro gain on channel 7 and channel 5 is your governor. If you are using a satellite only, put a standard 6ch Rx on the helicopter and use the included single wires that came with the 3GX and wire it up. This will put the gyro gain on channel 5 and you will be able to adjust it with the gear channel in your Tx under the gyro menu.

Hope this helps. Below is a video on setting up the DX6i with the 3GX. It's quick since I was using a DX8, but should cover what you need if you have not done so already.

3GX Setup Guide Part 1 Mounting & Wiring - YouTube

 

[Eggy 71]

I'm using a AR610 as a Rx. I've been wired up and running fine. It was just that I've never found a setup in rate mode to give me a stable heli. I've always flown in HH mode. I was just probing to see if I was missing something in setup or why there even is a rate mode for the gyro if I can't find that stable setting for hover.

 

[Tony]

Ah gotcha. Rate mode is there because some people do fly in Rate, but it's mostly the scale guys. It gives the tail a more realistic look when it's flying. If you want to fly in rate (highly NOT suggested) then put it in rate and set your gain to about 35. You will have to fly in IU1 so that you have a stable throttle curve. In fact, no curve, just a flat line will do best. Once you have that, put it into a hover in IU1 and see what way the tail is drifting. Use the linkage rod to adjust out the drift. Once you have the drift worked out, you can either keep flying in Rate, or do what you really should do and fly in HH mode which 'could' be more stable since you just dialed in the tail.

With MEMS gyros, you don't need to adjust the tail like that anymore, but you can if you want. Back in the piezoelectric gyro days, you HAD to do that setup step.