Props In vs. Props Out in FPV Drones: Why Propeller Spin Direction Matters

FPV drones blend high-speed flying with rapid direction changes. A key drone configuration decision is the propeller spin direction, known as “Props In” and “Props Out.” Understanding these configurations can significantly impact your flying experience. This article discusses the pros and cons of each.

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What’s “Props In” and “Props Out”?

Props in (also known as “standard” rotation): This is the more traditional configuration where the propellers at the front left and rear right spin clockwise, and the propellers at the front right and rear left spin counterclockwise. It’s the default in most flight controller software. And since front props spin towards the lens, it’s also called “props in”.

Props out (also known as “reverse” rotation): In this setup, the rotations of all the propellers are reversed – the front right and rear left propellers spin clockwise, while the front left and rear right spin counterclockwise. As the front props spin away from the camera lens, It’s also known as “props out”.

Which Is Better?

Both configurations will take your quad to the sky just fine, no configuration is inherently superior. But understanding the benefits and downsides of each configuration will help you make an informed decision.

Props in Pros:

1. Familiarity: Many pilots find this setup more intuitive, as it’s the traditional and default configuration used in most drones and flight controller software.

Props in Cons:

1. Debris on Lens: There’s a higher chance of debris being thrown towards the camera lens, which makes the lens dirty over time
2. Prop Wash: Props in configuration can sometimes lead to more prop wash, where the drone flies into its own turbulent air, potentially affecting stability.

Props Out Pros:

1. Enhanced Control: The reverse rotation can provide better control, especially in tight turns. The benefit and effect is especially noticeable for smaller quadcopters, like tiny whoops and other micro quads with low toque motors.
2. Less Obstruction: Lower chance of obstruction by branches and racing gates, as it would just bounce off obstacles in collisions.

Props Out Cons:

1. Debris on FC/ESC stack: There’s a higher chance of debris and dirt being thrown towards the FC stack
2. Adjustment Period: Pilots accustomed to the standard rotation may require time to adapt to the props out configuration.
3. Turtle Mode Issue: When you use turtle mode, the props runs the opposite direction when you are up side down, and so you are more likely to get your lens dirty.

Making the Choice

The decision depends on personal preference and requirements.

For tiny whoops and micro quads, props out is recommended.

For anything larger than 3″, like a 5″, I am happy to just run the default props in because the benefits in flight characteristics are less noticeable. And I don’t have to constantly remind myself to re-configure the drone after updating Betaflight. However other minor benefits still remain true such as less dirt gets thrown at the lens and less likely to get obstructed by branches and racing gates.

If your drone mostly hovers at the same spot, like a DJI Mavic does, then props in or props out make little difference.

However, if you encounter strange flight behaviour and issues, especially in cinewhoops, it’s worth experimenting with both props in and props out configurations, this often is the fix.

How to Reverse Motor Rotation

By default, Betaflight runs “props in”. Some BNF (bind and fly) prebuilt drones might come pre-configured as props out in the factory.

To configure your drone to run “props out”, you need to go to Betaflight Configurator, Configurations, under Mixer, enable “Motor direction is reversed”.

Then follow this tutorial to reverse the motor spin direction: https://oscarliang.com/change-motor-spin-direction-quadcopter/

Conclusion

Whether you choose props in or props out, understanding the implications of each setup is key to optimizing your FPV drone’s performance. Both configurations have their merits and can be effective in different scenarios. Ultimately, it’s about finding the balance that works best for your style and needs.

Edit History

• Jun 2017 – Article published
• May 2019 – Updated guide
• Jan 2024 – Updated guide