<p>Yaw authority and ease of mixing is generally the answer - since yaw response isn't necessarily the most linear, being able to have N number of motors contribute to yaw in one direction with the same number in reverse is the simplest motor output mixer configuration.
Tricopters do work and are relatively common among odd-numbered multicopters, but once you've exceeded four rotors, there aren't many meaningful performance improvements possible for the added complexity of requiring an odd number of motor outputs and doing a custom mix for that.
There are some slightly exceptional cases such as a forward puller motor mounted perpendicular to an otherwise conventional even-motor copter frame (see FliteTest MilleniumFalcon), but these aren't really a convention odd-numbered motor copter configuration.</p>

CC BY-SA 4.0
2020-04-14T19:54:50.620Z
2020-04-21T02:10:28.653Z
2020-04-21T02:10:28.653Z
Tehllama
<p>The most common types of multirotors are <a href="https://3dinsider.com/hexacopters-quadcopters-octocopters/" rel="nofollow noreferrer">quadcopters, hexacopters and octocopters</a> (with four, six and eight rotors respectively).</p>
<p>Are there scientific reasons why most drones are built with an even number of rotors?</p>

<multirotor><rotors>
Why are most multirotors built with an even number of rotors?
TheSimpliFire
# Why are most multirotors built with an even number of rotors?

(Asked by: username_0 on 2020-04-14)

The most common types of multirotors are [quadcopters, hexacopters and octocopters](https://3dinsider.com/hexacopters-quadcopters-octocopters/) (with four, six and eight rotors respectively).

Are there scientific reasons why most drones are built with an even number of rotors?

**Tags:** multirotor, rotors

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## 1 answers

### Answer by username_1 on 2020-04-14. Score: 17 | Accepted answer

Yaw authority and ease of mixing is generally the answer - since yaw response isn't necessarily the most linear, being able to have N number of motors contribute to yaw in one direction with the same number in reverse is the simplest motor output mixer configuration.
Tricopters do work and are relatively common among odd-numbered multicopters, but once you've exceeded four rotors, there aren't many meaningful performance improvements possible for the added complexity of requiring an odd number of motor outputs and doing a custom mix for that.
There are some slightly exceptional cases such as a forward puller motor mounted perpendicular to an otherwise conventional even-motor copter frame (see FliteTest MilleniumFalcon), but these aren't really a convention odd-numbered motor copter configuration.


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