Expo Throttle Curve in "Loiter" mode? Yes/No?

I have a larger Hexa (Vulcan 1200mm) build. I was observing another operator having trouble with Vulcan in Stabilize mode and thought of helping by applying curves options in Throttle for a looser mid throttle hover. I suggested flying in Loiter but he wanted “to become an better pilot” etc… NOW: Is Expo ignored in Loiter? OR: Is expo counterproductive to Loiter? I am trying to get confidence in flying this bird for me and my friend.

Just for clarity, do you mean throttle expo applied in the RC transmitter curves or in Arducopter parameters (MOT_THST_EXPO)?

Yes. I just applied it to the Taranis radio.

It will affect all flight modes since it modifies the PWM signal being sent by the transmitter. For Loiter, Pos Hold, and Alt Hold, mostly it will just make the throttle (climb rate) deadzone larger, which may be undesirable as it will actually make altitude control more sensitive outside of the deadzone. This can be alleviated by making the deadzone smaller with the THR_DZ parameter.

This is was a measure taken for STABILIZE. I have a straight linear curve for the 1st mode which is default. If HOVER is a problem in the other modes you have mentioned, should I use the fix you suggested? It is a very heavy unit.

Yeah, reducing the size of the deadzone will let you use expo throttle for Stabilize while keeping the RC feel of altitude-controlled modes mostly the same.

So ditch the transmitter curves and just use this solution? I have two other modes with medium and heavy curves on a Taranis switch. The Taranis default curve is not purely linear when I see it. It has a little crook at the bottom to boost liftoff and then flattens out. My point is: should it be purely linear?

And thank you for all your help!

Oh I think I misunderstood.

Yes, Loiter would be best left with linear throttle. Probably the little crook at the end won’t make a big difference because takeoff won’t happen until you pass the mid-throttle deadzone, which is at 60% throttle or so.

My suggestion to make the deadzone smaller was in case you were planning on having throttle expo while flying in Loiter. But if your Taranis will use a different curve for Loiter vs. Stabilize, then there’s no need to do that.

Not to beat a dead horse, but is it better to THR_DZ parameter for STABILIZE or create the throttle curves in Taranis? I will leave the linear curve for Loiter. THR_DZ parameter will affect all MODES whereas I can control the STABILIZE with switches. The original idea was to help a lesser skilled pilot who insists on flying this large copter in STABILIZE. For the purpose of this drone (Agriculture) I will mostly fly in LOITER and AUTO once I get it tuned and working in a predictable way. (thx again)

I will study THR_DZ parameter now.

THR_DZ only affects Loiter and other altitude-controlled modes, so you don’t need to change it if you will continue flying Loiter and Alt Hold with a linear throttle curve.

That is Perfect, Thank you!