multirotor

{{Short description|Rotorcraft with more than two rotors}}

File:DJI Phantom 1 1530564a.jpg]]

A multirotorEarly in helicopter development,"multi-rotor" was used to refer to helicopters with two rotor assemblies or multicopter is a rotorcraft with more than two lift-generating rotors. An advantage of multirotor aircraft is the simpler rotor mechanics required for flight control. Unlike single- and double-rotor helicopters which use complex variable pitch rotors whose pitch varies as the blade rotates for flight stability and control, multirotors often use fixed-pitch blades; control of vehicle motion is achieved by varying the relative speed of each rotor to change the thrust and torque produced by each.

Due to their ease of both construction and control, multirotor aircraft are frequently used in radio control aircraft and unmanned aerial vehicle (UAV) (drone) projects{{cite web|title=AeroQuad - The Open Source Quadcopter|url=https://santuy69.com/|access-date=2012-01-05|archive-url=https://web.archive.org/web/20120103092559/http://aeroquad.com/|archive-date=2012-01-03|url-status=dead}}{{cite web|url=http://multicopter.org/wiki/Multicopter_Table|title=Multicopter Table|work=multicopter.org|access-date=30 June 2015|archive-date=6 November 2011|archive-url=https://web.archive.org/web/20111106071900/http://multicopter.org/wiki/Multicopter_Table|url-status=dead}}{{cite web|url=http://uavp.ch/moin/FrontPage|title=FrontPage - UAVP-NG - The Open Source Next Generation Multicopter|work=uavp.ch|access-date=30 June 2015}}{{cite web|url=http://ng.uavp.ch/|title=FrontPage - UAVP-NG - The Open Source Next Generation Multicopter|work=uavp.ch|access-date=30 June 2015}}{{cite web|url=http://www.diydrones.com/|title=DIY Drones|work=diydrones.com|access-date=30 June 2015}}[http://www.openpilot.org/ OpenPilot] {{webarchive|url=https://web.archive.org/web/20110527225811/http://www.openpilot.org/ |date=2011-05-27 }} Open source UAV autopilot for multirotors in which the names tricopter, quadcopter, hexacopter and octocopter are frequently used to refer to 3-, 4-, 6- and 8-rotor rotorcraft, respectively.{{cite web|url=https://www.kfx450central.com/members/frasacuan.1599218/#about|title=How to Pick The Best Multirotor Frame|work=My First Drone|access-date=30 June 2015|archive-url =https://web.archive.org/web/20140403153424/http://myfirstdrone.com/tutorials/best-multirotor-frame/|archive-date =3 April 2014}} There is also the X8 (also called octo-quad) configuration that is similar to the quadracopter design, except that it has eight rotors; the lower of which have a reversed rotation direction.{{cite web|url=https://ardupilot.org/copter/_images/motororder-octoquad-x-2d.png|title=Octo Quad|work=ardupilot.org|access-date=30 December 2019}}

File:The Hexacopter.jpgIn order to allow more power and stability at reduced weight, coaxial rotors can be employed, in which each arm has two motors, running in opposite directions which cancels out rotational torque (one facing up and one facing down).{{cite web|url=http://www.coptercraft.com/multirotor-frame-configurations/|title=Multirotor Frame Configurations|work=Coptercraft|access-date=23 December 2015}}

File:Lifting-Wing Multicopter.png

Also possible is the addition of horizontal propellers[http://www.unmannedsystemstechnology.com/company/vertical-technologies/ Vertical technologies DeltaQuad]{{Cite web |url=http://px4.io/portfolio/quadranger-vtol/ |title=QuadRanger VTOL |access-date=2018-04-29 |archive-date=2018-11-06 |archive-url=https://web.archive.org/web/20181106145016/http://px4.io/portfolio/quadranger-vtol/ |url-status=dead }}[https://newatlas.com/skyprowler-fixed-wing-quadcopter/36154/ SkyProwler] These types of rotorcraft (which have just 4 vertical propellers) are called quadplanes.[http://ardupilot.org/plane/docs/quadplane-overview.html Quadplane term]It can also be possible by adding additional nonhorizontal wings, which are called lifting-wing multicopters.{{Cite book |last1=Xiao |first1=Kun |last2=Meng |first2=Yao |last3=Dai |first3=Xunhua |last4=Zhang |first4=Haotian |last5=Quan |first5=Quan |chapter=A Lifting Wing Fixed on Multirotor UAVs for Long Flight Ranges |date=2021-06-15 |title=2021 International Conference on Unmanned Aircraft Systems (ICUAS) |chapter-url=https://doi.org/10.1109/icuas51884.2021.9476859 |publisher=IEEE |pages=1605–1610 |doi=10.1109/icuas51884.2021.9476859|arxiv=2006.15579 |isbn=978-1-6654-1535-4 }}{{Cite journal |last1=Zhang |first1=Haotian |last2=Tan |first2=Shaochang |last3=Song |first3=Ziming |last4=Quan |first4=Quan |date=June 2022 |title=Performance Evaluation and Design Method of Lifting-Wing Multicopters |url=https://doi.org/10.1109/tmech.2021.3090667 |journal=IEEE/ASME Transactions on Mechatronics |volume=27 |issue=3 |pages=1606–1616 |doi=10.1109/tmech.2021.3090667 |issn=1083-4435|url-access=subscription }}{{Cite journal |last1=Quan |first1=Quan |last2=Wang |first2=Shuai |last3=Gao |first3=Wenhan |date=March 2025 |title=Lifting-Wing Quadcopter Modeling and Unified Control |url=https://doi.org/10.2514/1.g008134 |journal=Journal of Guidance, Control, and Dynamics |volume=48 |issue=3 |pages=689–699 |doi=10.2514/1.g008134 |arxiv=2301.00730 |bibcode=2025JGCD...48..689Q |issn=0731-5090}}