Betaflight’s Dynamic Idle feature can improve turn responsiveness, low throttle stability, and prop wash handling for FPV drones. In this guide, we’ll walk you through enabling and configuring Dynamic Idle to achieve optimal results for your specific drone.
Table of Contents
Activating Betaflight Dynamic Idle
To enable Dynamic Idle, follow these steps:
- Open the Motors tab in Betaflight Configurator and enable bi-directional D-shot. This allows Betaflight to read the RPM of each motor. If you have already enabled the RPM filter, then you don’t need to do this step.
- Navigate to the PID Tuning tab and locate “Dynamic Idle” in the right-hand pane, under “Throttle and Motor Settings.” Set an appropriate Dynamic Idle RPM value based on your drone’s propeller size (e.g., 3000-3500 RPM for 5-inch props). Higher pitch props require lower values, while lighter props need higher values.
Note: When Dynamic Idle is set, the static Motor Idle percentage in the Motors tab is automatically disabled.
Finding Ideal RPM Value
The recommended Idle RPM value depends on the authority of your drone, which is decided by the strength of the motors, pitch and size of the propellers etc. For example, drones with low authority (e.g. low pitch propellers and weak motors) generally require higher RPM value. When it’s windy you can also set this higher to better counter external forces in low throttle.
Value too high, the drone will feel floaty, and you lose hang time when you perform inverted moves because the motors push harder towards the ground. A high value will also tend to make the quad hover a little more even at zero throttle, making throttle management a little harder. When value is too low, you risk low throttle instability.
To “tune” dynamic idle value, it depends on what ESC idle you had previously (default is 5.5%), test your motor in the motor tab, you can use a smoke stopper or bench power supply to limit current in case it goes out of control. Spin the motor at the ESC idle value, e.g. for 5.5%, move slider to around 1055, and see what the reported RPM value is (it will only show this if you enable bi-directional DShot). Then this RPM value would be the ideal value for your dynamic Idle value (divide it by 100). Some people prefer to use a percentage of the hover RPM as their dynamic idle value, such as 40% or 50%. You can display real time RPM in your OSD.
Here’s a general guideline I personally follow, but these are NOT optimal values for all drones. You should always “tune” your dynamic idle value based on your specific setup and requirements as described above.
| Prop Sizes | High Pitch Props | Low Pitch Props |
| 31mm/1.2″ | 84 | 167 |
| 40mm/1.6″ | 62 | 124 |
| 2″ | 50 | 100 |
| 2.5″ | 40 | 80 |
| 3″ | 33 | 66 |
| 3.5″ | 28 | 57 |
| 4″ | 25 | 50 |
| 5″ | 20 | 40 |
| 6″ | 16 | 33 |
| 7″ | 14 | 28 |
The Importance of Dynamic Idle
Without Dynamic Idle, Betaflight sets the minimum RPM of motors by sending a fixed value (with a default idle speed of 5.5%). This can result in inconsistent RPM across all motors due to slight KV differences and battery voltage fluctuations (e.g., idle RPM at 4.2V will be faster than at 3.8V).
With Dynamic Idle, however, Betaflight can detect and read each motor’s RPM, allowing you to set the minimum RPM more precisely. But how does this improved accuracy benefit prop wash performance?
How Dynamic Idle Reduces Prop Wash
When prop wash occurs, the flight controller attempts to stabilize the quadcopter by rapidly speeding up or slowing down the motors. Without Dynamic Idle, the minimum RPM your motors can reach is 5.5% by default. In contrast, when Dynamic Idle is enabled, Betaflight can command the motors to drop to 0% RPM. This enhanced braking capability noticeably improves prop wash handling.
Wrapping Up
Enabling Dynamic Idle can lead to a notable improvement in prop wash performance. However, numerous other factors can also impact prop wash handling. For more tips on improving your drone’s performance, check out our comprehensive tuning guide: https://oscarliang.com/fpv-drone-tuning/
7 comments
What’s confusing me is the dynamic idle chart. It’s nearly the exact opposite of the recommended values that Chris gave in his PID-Tuning clip on Youtube (youtube.com/watch?v=1oYoVE4xu1U&t=786s)
I think he might have them the wrong way around. The Dynamic Idle value corresponds to motor RPM—low-pitch props generate less thrust, so they require higher RPM, meaning a higher Dynamic Idle value. The opposite applies to high-pitch props, which produce more thrust and need lower RPM, resulting in a lower Dynamic Idle value.
Hey Oscar,
first of all, let me thank you for your reply. I have spent the last few days looking into the subject, reading various articles and watching videos. In the end I came to the conclusion that neither the size of the propeller or it’s pitch have anything to do with the dynamic idle value.
There are various theories as to what might be better, but in my opinion it is simply a matter of ensuring that the motors do not stop or even turn backwards during changing inflow conditions, which can lead to problems when starting up again.
The values of 3000 – 3500 rpm recommended by Betaflight are generally valid in my opinion and lead to the same speed for both small propellers and large propellers.
https://github.com/bird-sanctuary/bluejay/wiki/Setup#dynamic-idle
Thanks for this link! It contains an important note! I had failure, when i tryed to use dynamic idle in my 1s tinywhoop with bluejay esc! I have tryed to set the big idle values and have had no success!
Shouldn’t the below be opposite, since higher pitch need lower values. Original quote:
“(…)
20-30 for prop pitch 3.5
(…)”
Yes you are right, it’s a typo. Thanks for the correction.