Rate/Acro Mode VS Horizon/Self-Level Mode

When it comes to flying multirotors, generally there are two main flight modes we use, one is acro mode (AKA manual mode or rate mode), and the other is self level mode.

What is Rate Mode and Self-Level Mode?

Self-level mode is an assisted flight mode. When there are no stick inputs on the TX, the flight controller always attempts to keep the quadcopter in a neutral, level position. On the other hand, rate mode doesn’t level the aircraft automatically but requires constant manual adjustment to keep the quad from losing control and crashing into the ground.

Rate mode uses only the Gyro sensor, while self-level mode uses both Gyro and Accelerometer.

Self-Level Modes: Angle and Horizon

In Betaflight and Cleanflight, there are 2 different self-level modes: Angle and Horizon mode, and there is one major difference between them.

Angle Mode

In Angle mode your stick controls the tilt angle of your aircraft. When your stick reaches its maximum position the copter will stop and hold there as it has reached the max tilt angle allowed. When you release the stick back to the centre, the angle of the aircraft will follow the stick back to horizontal level.

Horizon Mode

Similar to Angle mode, Horizon mode still works to keep the craft level when there are no inputs, but it also allows you to do flips and rolls when the stick is at full deflection. However doing aerobatics in this manner feels more like a toy grade “push-button” flip system.

This is where Rate mode come in…

What is Rate Mode?

When you try Rate mode (or commonly known as Acro mode) for the first time, it can feel like you are controlling a puppet clown, riding a unicycle, balancing a ball on his head! This inherent instability can result in costly crashes, and because of this Acro mode can be quite intimidating for beginners.

In Rate mode the pilot uses the stick to control the drone’s angular velocity of rotation. That means if you move your pitch stick forward and hold it, the copter will continue to rotate at a constant rate, instead of just remaining at the corresponding angle like it would in self-level mode. In Rate mode, when you let go of the stick, the copter will maintain its current attitude (angle) and will not return to level, unless you move your pitch stick in the opposite direction.

To sum up the difference:

Angle mode:

  • Remains level without stick input
  • Pitch and roll inputs determine how far the craft will rotate on the given axis

Rate / Acro mode:

  • Requires stick input to manually return to level
  • Pitch and roll inputs determine how fast the craft rotates on the axis

Why Fly Acro Mode?

Self-level mode is easier for beginners, because of the predictable behaviour: let go of the stick, and your drone will just return to level. But trust me, Acro Mode is the “only way” to fly a mini quad in FPV.

My advice to beginners – only use Angle mode at the beginning to learn how your quad responds to the sticks, as soon as you are confident about flying, switch to Acro mode straight away.

Here are some of the advantages and benefits of flying in Acro mode:

  • Rate mode is great for acrobatics such as flips and rolls, sometimes being able to do these tricks fast and slow can be more visually engaging than the “blink-and-you-miss-it” flips in Horizon mode
  • You have more control when flying FPV once you master rate mode, because you don’t have to fight with ACC sensor and constantly adjust your stick inputs
  • You only control the quad when it is needed, reducing stick input can make your flying smoother and faster
  • Once it “clicks”, the control in Rate mode is actually more intuitive, fluid and natural
  • Flight performance is more stable with less oscillations and wobbles due to the fact that the accelerometer is disabled which makes Acro mode the better choice for capturing aerial video, especially when camera gimbals are not used
  • One fewer sensor is used means one fewer failing point, also disabling the Accelerometer can free up FC processing power for higher looptime or other peripherals

Rate mode is not easy to master, but you will get a great sense of satisfaction when you start getting the hang of it. And when you start doing tricks, you really feel like you are accomplishing something.

Some people use a switch to return to Self-level mode when they panic in Acro mode, and this might be excusable, but only to a certain point! Rather than training yourself to quickly use a switch, I think learning to fly Acro “full time”, and regain control from an iffy situation is the better skill to develop in the long run.

So How Do I Hover?

No! We don’t hover! :)

… Well, we do but we rarely need to hover during an FPV flight. I know it’s easy to panic and just rely on the software to return the quadcopter to level, but it’s really bad for your learning progress in the long run. It is also easy to spot FPV videos when the pilot is using Angle mode, they look very jerky with none of the fluidity you get from a good Acro pilot.

You have to train yourself to get used to hovering in Acro mode, memorizing the camera tilt angle, and where the horizon appears on your screen when the quad is level.

How Long Does It Take To Learn Rate Mode

Mastering rate mode doesn’t happen overnight. For beginners, you should expect to crash a lot before getting a hang of it. It can be a frustrating process which is why, if you can, we advise you practise in a flight simulator first.

Getting a resilient quadcopter frame and lots of cheap and durable propellers will help a lot. Go somewhere open and without too many obstacles and people, some grass is good to soften the inevitable crashes too. Stick with it, it might take hours or days, but it will click one day and it will feel great, I promise.

Also, beginners might find it helpful to add some expo that creates a curve to your TX stick inputs. Using expo means stick inputs are no longer linear, so if you find your quad is over-reacting to your inputs, adding expo will give you more fine control around the middle stick range. As you get more used to the characteristics of your quad, dial the expo down to where you feel comfortable. Later on you might also want to increase RC Rate to make flips and rolls faster.

Here is a great discussion of someone who was learning how to fly FPV in Rate mode.

Flying Rate Mode Line of Sight

Here is the bad news :)

Even if you have mastered flying rate mode in FPV, flying rate mode in LOS is a completely different beast, it can feel like you are learning to fly all over again. I know that it’s really all about FPV but it’s useful to continue practicing your LOS skills. In the case of system failure, your skill at flying LOS might mean the difference between watching your craft disappear forever, and being able to fly it home again.

Edit History

  • Mar 2015 – Article created
  • Dec 2017 – Updated

25 thoughts on “Rate/Acro Mode VS Horizon/Self-Level Mode

  1. MrTom

    I have a SkyViper V2400HD. Nice machine to learn to fly LOS self-level mode. But I’ve recently purchased a Wizard x220 and a 4S battery. This thing is a beast! Spent some time programming it. I didn’t realize I had enabled Acro mode. My bro an I went to a field to fly. He hovered a bit okay. Then it was my turn. Tried to fly it LOS and it only lasted 5 seconds in the air. Bent a prop when it violently hit the grass upside down. I knew there was much to learn.

    So I purchased a USB flight cable to attach my transmitter to my computer. Funnest thing ever. Used FPV Freerider & FPV Event for a while. I’m now playing DRL Simulator. I can’t believe that one is free! Now that’s an amazing FPV sim. I love the tutorial modes, that’s what I was looking for in a sim trainer. Not just “here ya go dude, now fly” like some of them.

    Anyway, I keep getting better and better using my sims, that soon enough I’ll be able to go out in the field and maybe keep the quad in the air for more than 5 seconds. ;)

    Reply
  2. Andre

    Hi Oscar, this post helps begginers a lot…what would be ur suggestions on the best FCs for mini racers that support self-level mode, i mean…does any actual FC still support it? Couldnt find any reference to it in the LUX V2 description for example :( ….Whats the best one in ur opinion? thanks a lot !!! ….. ^^

    Reply
    1. Oscar Post author

      any FC should support self-level (at least for Cleanflight and Betaflight). Every MPU has both Gyro and Accelerometer.
      LUX V2 does too.
      Depends on what feature you are looking for there is no one “best FC”. check out our Top5 FC articles for some ideas.

      Reply
  3. Robert

    Hi, thanks for the detailed article!

    I haven’t flown acro/rate/manual mode yet, but it sounds like ‘manual’ mode is a complete misnomer. It isn’t really ‘manual’ at all, and ‘rate’ or ‘acro’ are much more appropriate terms.

    I imagine that if it were truly manual, then a quad wouldn’t hold its attitude when centering sticks. Inertia would cause it to continue to rotate even after discontinuing control input. A truly manual mode would require constant compensating stick movements to counter that inertial continued rotation.

    Is this analysis correct, or am I misunderstanding something fundamental in the article?

    Reply
    1. Oscar Post author

      it sounds like you haven’t really flown it yet… Once you compare self-level mode and “manual” mode you might feel differently.

      Reply
  4. Youri Rombouts

    How do you actually change modes on baseflight?

    I’m using a raspberry pi to talk to the naze32 through a USB connection but i’m having a problem which I believe is called the “bunny hop” for obvious reasons. I am wondering if there is a way to change to angle mode so my quadcopter can stay leveled without it slamming itself into the floor. I am a complete newbie in this area so please don’t assume I know anything.

    Thanks in advance

    Youri Rombouts

    Reply
  5. Byron

    Good day!

    I im learning to fly in a rate mode of toy grade quads . Din in preparation to a hobby grade quads from 120-130mm class. Is this same whem i shift to a hobby grade tx flying in acro mode?
    Thank you

    Reply
    1. Oscar Post author

      on some toy grade quads rate mode work slightly different, but regardless that shouldn’t stop you from upgrading and learn it on a hobby grade quad :) just make sure you practice on soft grass and get plenty of propellers, you should be fine.

      Reply
  6. Frank Owen

    Ok, I am getting the idea that rate mode has a lot to offer, but it is hard at first. And quite a bit different than auto-level. So my question is: once you switch, does it become nearly impossible to switch back to auto-level, because it feels “too weird”? If I learn rate-mode, will I have a hard time flying toy-grade quads that don’t have rate-mode?

    Reply
    1. Oscar Post author

      not really :) it’s like learning riding a bike then learn swimming, you won’t forget one or the other :)

      Reply
      1. Chris

        I think it’s more like learning to drive a car with a manual transmission. You can always go back to driving an automatic later without any issues.

  7. Jonathan Roung

    Oscar, I’ve been following your posts and I LOVE the insights you share. Here’s one for you:

    I want to fly acro/rate mode for pitch, but auto-level mode for roll.

    I’m assuming Betaflight’s ‘Horizon mode’ would accomplish this, by setting pitch stick deflection to 0° (essentially putting pitch in rate mode all the time) and setting roll stick deflection to, say, 70° (so that barrel rolls can still be completed during extreme stick deflections).

    What are the odds you have explored this and could comment?

    Reply
    1. Oscar Post author

      Hi Jonathan,
      As far as I know you can’t mix flight modes.
      but what do you want to do this?
      thanks
      Oscar

      Reply
  8. soli_sal

    Hi, I am building a quadrotor for first time and I implemented rate mode successfully on that…
    The problem is I can’t implement angle mode over the rate mode!
    Rate mode works great, but when I enable angle mode, quadrotor is too slow to stabilize with some overshoot. It takes a few second to go to desired angle and when I release the stick, it returned in same way…
    This is what I did in code:

    rate_needed = PIDcalculate(&pid_roll_stab, desired_angle, current_angle);
    pwm_for_roll = PIDcalculate(&pid_roll_rate, -rate_needed , current_rate_gyro);

    Rate PID has P,I coefficents and Angle PID has P for now…
    Thank you

    Reply
  9. E.L.K.

    Hi Oscar!

    I finished a build of 250 quad recently: https://dl.dropboxusercontent.com/u/54741704//Other/copter/el%20el/assembled-for-first-flight.jpg

    After some doings with the settings and radio and so on I finally got it to fly ok in autolevel. But in rate mode there is slight angle drift on pitch (it increases incline to back).

    The trick here is that quad actually not balanced – it’s center of gravity is ~2.5 cm to back from the center. I know that it possibly will fly better if balanced, but I just want to understand where this angle drift comes from so I experiment with unbalanced quad. As far as I understand, the “rate” mode is something like “angle lock” mode – sticks control the speed of angle change, and when sticks are not touched it should maintain the set angle. But it does not. What confuses me a lot is that the speed of drift is different over time. At the flight start (battery full) – the quad maintains angle ok, but as closer it gets to empy battery, the significanlty it starts to change angle by itself (up to about a degree per sec or even more).

    Why it can behave like that? Can you, please, recommend me a direction to continue investigation?

    Reply
    1. E.L.K.

      It seems that the problem was “I ” in PID too low for pitch, so it wasn’t able to stabilize. I increased I (almost twice, actually) and now it locks it’s angle almost pefrectly.

      Reply
    2. Oscar Post author

      does it drift to different direction or always that direction? i think it might be I gain too low?
      are you using 5030 props? it could also be that your quad is under powered…
      lastly… i would really appreciate it if you could post your questions on the forum: http://intofpv.com … I only check my blog comments once a week, but I use the forum everyday!

      Reply
  10. moosestang

    Is there a way to limit the angle in rate mode or even horizon mode? My biggest problem is giving it to much pitch and slamming into the ground. I’m going to try lowering the level pid’s in angle mode until i can get some smooth fpv video like rate mode. I want to learn to fly rate, but flying fpv i like to give it full pitch without flipping over.

    Reply
    1. Oscar Post author

      yes, use angle mode, it won’t allow you to go over 45 degree by default, you can change this angle limit in CLI i think. I don’t think it’s possible though in rate / horizon mode.

      Reply
      1. Jonathan Roung

        In Cleanflight configuration software, this is done through CLI command “set max_inclination_angle = XX” (or “max_angle_inclination” in Betaflight). You might also want to adjust your expo to account for the changes this would make to your corresponding stick deflections.

  11. Chiggz

    I’d highly recommend people grab themselves a simulator that supports FPV or quadcopters, like RealFlight 7.5

    I use to fly auto level modes and assisted flying modes all the time, but I spent a couple of hours on the sim, and the next time I went flying at the park, I had to turn auto leveling mode off as it felt too weird :P

    Now I’m an avid flyer of rate/acro mode and highly recommend it to others. Its much easier to be smoother around corners and generally push a bit harder.

    Reply
    1. Jonathan Roung

      LiftOff is a great new software program – joint venture between FPV gurus FatShark and gaming wizards Steam. It reads my Taranix X9D perfectly, has settings for customizing a quad to match your real-life setup (lipo size, PID settings, FPV cam angle, etc), and even offers a multiplayer simulator.

      Reply

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