When it comes to flying multirotors, generally there are two main flight modes we use. One is acro mode, and the other is self-level mode.
What is Self-Level Mode?
In self-level mode, when you let go off the control stick, the drone would return to its levelled position. It’s like there was an invisible hand keeping the drone levelled at all time whenever it’s not controlled by the pilot.
In Betaflight, there are 2 different self-level modes: Angle mode and Horizon mode. They are very similar with a little difference.
In Angle mode your stick controls the tilt angle of your aircraft. When moving the roll/pitch stick to its maximum position, the drone will also reach the maximum angle it’s allowed to tilt (defined by the user), and it won’t flip over. As you release the stick back to centre, the aircraft will also return to its level position. This is quite useful for flying in tight spaces, such as inside the house.
Exactly like Angle mode, Horizon mode would keep the craft level when there are no stick inputs. But the drone will flip over 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 Acro mode comes in…
What is Acro Mode?
Acro mode is also known as manual mode and rate mode. Acro mode doesn’t level the aircraft automatically, it will hold its roll and pitch position when you let go off the stick. Therefore the pilot would have to constantly make manual adjustments to keep the quadcopter from losing control and crashing into the ground (hence the name manual mode).
In Acro mode, you are controlling the drone’s angular velocity of rotation with the stick instead of the angle. That means if you push your pitch stick forward and hold it there, the drone will continue to rotate at a constant rate, instead of just remaining at an angle like it would in self-level mode. To return to its level position, you would have to move the stick to the opposition direction.
To sum up the differences:
Angle / Horizon mode:
- Uses both Gyro and Accelerometer sensors
- Remains level without stick input
- Pitch and roll inputs determine how far the craft will rotate on the given axis
Rate / Acro mode:
- It uses only the Gyro sensor
- Requires stick input to manually return to level
- Pitch and roll inputs determine how fast the craft rotates around 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 – switch to Acro mode as soon as you can!
Here are some of the advantages of flying in Acro mode:
- The biggest benefits would be the smoother and finer control you get from acro mode; In Self-Level mode you have to “fight” with ACC sensor and constantly adjust your stick as it’d return to level when you let go. In acro mode, you don’t need to hold the sticks, instead you only need to make small and precise corrections which makes your flying smoother
- 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
- 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. This 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 by disabling the Accelerometer you can free up FC processing power for higher looptime or other peripherals
When you try Rate 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.
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.
Make sure to check out our tutorial on how to fly FPV.
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 will slow down your learning progress in the long run. It is also easy to spot FPV videos when the pilot is using Angle mode, they’d look 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 quite a few times 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, without obstacles and people, grass is useful for softening the inevitable crashes too. Stick with it, it might take 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 it’s all about FPV really for most people, but it’s useful to continue practicing your LOS skills. When your FPV system failed, your skill at flying LOS might mean the difference between watching your craft disappear over the horizon, or being able to recover and fly it home manually.
How to Enable Acro Mode in Betaflight?
In the modes tab in Betaflight, there is no “Acro Mode” option, so how do I enable it?
Acro mode is the default mode in Betaflight. As long as you are not in Horizon or Angle mode, you are in Acro mode when you arm the quad.
Just assign a switch to ARM and do not trigger the two self-level flight modes, you will be flying in Acro mode.
- Mar 2015 – Article created
- Dec 2017 – Updated, added “How to enable Acro mode”