Throttle scaling / limit for novice pilots?

ArduCopter Copter 4.6
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TLDR: what is the best way to limit motor output in order to reduce performance for a novice pilot?

I have three copters with hover throttle between 0.12 (3.5") and 0.20 (6"). I’m a relatively inexperienced pilot - I can do a few tricks with fixed wing, but still very much getting to grips with quadcopters.
The 6" quadcopter is relatively docile, and I find it relatively easy to fly line of sight in stabilise mode. The 3.5" is a bit of a handful in stabilise and acro - dry weight is 152g and logs show peak climb rates over 25m/s.

I’ve seen that Betaflight has a throttle scaling option, which is useful for newbs and overpowered copters. Is there a direct equivalent in Arducopter? Ideally I’d like to scale maximum throttle down to around 75-80%.

I think I can reduce MOT_SPIN_MAX, but I presume that could adversely affect responsiveness and necessitate a new tune? Is there a better way?

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Hi Giles,

I don’t think we have a parameter for this but on the other hand, if you fly it in a stable hover in AltHold mode for 10 or 20 seconds the hover throttle will be learned and that will actually affect the pilot’s scaling in manual modes (stabilise, acro). So if the pilot raises the throttle to mid stick, the output will be close to the throttle required to hover. There’s a limit on how low the hover throttle learning will go though so on a very over powered copter you might have to set the hover throttle manually and then disable the learning.

This is described on the wiki here.

We also have current limiting but this requires using a battery monitor which includes measuring the current

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Thanks. I’ve set hover throttle manually on the 3.5", and disabled learning. It maintains altitude well with throttle at mid stick in both Alt Hold and Loiter. It’s Stabilise and Acro which I find challenging. There’s usually a slight throttle adjustment needed when switching from Alt Hold to Stabilise or Acro, but it’s gentle cruising where I find it hard to modulate the throttle. I guess that’s to be expected when 50% throttle stick is around 12% CTUN.ThO.

I considered reducing maximum throttle at the transmitter (RadioMaster Pocket with EdgeTX), but I think I’d have to jump through hoops to keep hover throttle in Alt Hold & Loiter at 50% stick travel.

ETA: Logs show RCIN.C3 in the range 1400-1600 with gentle flying in Acro mode, at a mean GPS speed of 12m/s. I’ll try to get some more time on the simulator.

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You can adjust MOT_PWM_MAX but then you will need to do tuning again including adjusting MOT_THST_EXPO.

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Thanks. Basic tune plus autotune (including YawD etc.) takes six or seven flights on the 3.5", so I reluctantly decided that the pragmatic way was to reduce maximum throttle in EdgeTX. It’s not an ideal solution, but it seems to function as intended, and I can gradually increase the maximum throttle as my skills improve, without having to re-tune.

For reference, I did the following to reduce maximum throttle in EdgeTX:

  1. Create duplicate throttle input that is active when SC is down (Acro mode)
  2. Modify original throttle input to be active when SC is not down
  3. Create custom 3 point curve (pt1: x=-100 y=-100, pt2: x=0 y=0, pt3: x=100 y=80)
  4. Assign custom curve to the new throttle input (the one that is active with SC down)

I’m using two transmitter switches to select between six flight modes, so in my case the custom throttle curve also applies in RTL mode (and I presume has little to no effect in that mode). Zero throttle is still zero throttle and mid is still mid, so I think arm/disarm and throttle behaviour on flight mode switch is still correct.
Obviously the throttle RCIN slope gradient is different above and below mid throttle. I’ve yet to judge whether that is an issue or not.