Editing Unmanned aerial vehicle (section)

==Design==
[[File:UAV Physical and hardware.jpg|thumb|General physical structure of a UAV]]

Crewed and uncrewed aircraft of the same type generally have recognizably similar physical components. The main exceptions are the [[cockpit]] and [[Environmental control system (aircraft)|environmental control system]] or [[life support system]]s. Some UAVs carry payloads (such as a camera) that weigh considerably less than an adult human, and as a result, can be considerably smaller. Though they carry heavy payloads, weaponized military UAVs are lighter than their crewed counterparts with comparable armaments.

Small civilian UAVs have no [[life-critical system]]s, and can thus be built out of lighter but less sturdy materials and shapes, and can use less robustly tested electronic control systems. For small UAVs, the [[quadcopter]] design has become popular, though this layout is rarely used for crewed aircraft. Miniaturization means that less-powerful propulsion technologies can be used that are not feasible for crewed aircraft, such as small electric motors and batteries.

Control systems for UAVs are often different from crewed craft. For remote human control, a camera and video link almost always replace the cockpit windows; radio-transmitted digital commands replace physical cockpit controls. [[Autopilot]] software is used on both crewed and uncrewed aircraft, with varying feature sets.<ref>{{Cite web |title=Design, Simulation and New Applications of Unmanned Aerial Vehicles |url=https://www.mdpi.com/topics/UAV |access-date=2023-03-24 |website=www.mdpi.com |language=en}}</ref><ref>{{Cite journal |last1=Nagel |first1=Huub |last2=Bondt |first2=Geert |last3=Custers |first3=Bart |last4=Vergouw |first4=Bas |date=16 July 2016 |title=Drone Technology: Types, Payloads, Applications, Frequency Spectrum Issues and Future Developments |url=https://www.researchgate.net/publication/309184029 |journal=The Future of Drone Use}}</ref><ref>{{Cite journal |last1=da Silva |first1=F.B |last2=Scott |first2=S.D |last3=Cummings |first3=M.L |date=December 2007 |title=Design Methodology for Unmannded Aerial Vehicle (UAV) Team Coordination |url=https://dspace.mit.edu/bitstream/handle/1721.1/46732/HAL2007_05.pdf |journal=Design Methodology for Unmannded Aerial Vehicle (UAV) Team Coordination}}</ref>

===Aircraft configuration===
UAVs can be designed in different configurations than manned aircraft both because there is no need for a cockpit and its windows, and there is no need to optimize for human comfort, although some UAVs are adapted from piloted examples, or are designed for optionally piloted modes. [[Air safety]] is also less of a critical requirement for unmanned aircraft, allowing the designer greater freedom to experiment. Instead, UAVs are typically designed around their onboard payloads and their ground equipment. These factors have led to a great variety of airframe and motor configurations in UAVs.

For conventional flight the [[flying wing]] and [[blended wing body]] offer light weight combined with low [[drag (aerodynamics)|drag]] and [[stealth aircraft|stealth]], and are popular configurations for many use cases. Larger types which carry a variable payload are more likely to feature a distinct [[fuselage]] with a tail for stability, control and trim, although the [[wing configuration]]s in use vary widely.

For uses that require vertical flight or hovering, the tailless [[quadcopter]] requires a relatively simple control system and is common for smaller UAVs. [[Multirotor]] designs with 6 or more rotors is more common with larger UAVs, where redundancy is prioritized.<ref>{{Cite journal |last1=Torres-Sánchez |first1=Jorge |last2=López-Granados |first2=Francisca |last3=Castro |first3=Ana Isabel De |last4=Peña-Barragán |first4=José Manuel |date=2013-03-06 |title=Configuration and Specifications of an Unmanned Aerial Vehicle (UAV) for Early Site Specific Weed Management |journal=PLOS ONE |language=en |volume=8 |issue=3 |pages=e58210 |doi=10.1371/journal.pone.0058210 |issn=1932-6203 |pmc=3590160 |pmid=23483997|bibcode=2013PLoSO...858210T |doi-access=free }}</ref><ref>{{Cite journal |last1=Torres-Sánchez |first1=Jorge |last2=López-Granados |first2=Francisca |last3=De Castro |first3=Ana Isabel |last4=Peña-Barragán |first4=José Manuel |date=2013 |title=Configuration and specifications of an Unmanned Aerial Vehicle (UAV) for early site specific weed management |journal=PLOS ONE |volume=8 |issue=3 |pages=e58210 |doi=10.1371/journal.pone.0058210 |issn=1932-6203 |pmc=3590160 |pmid=23483997|bibcode=2013PLoSO...858210T |doi-access=free }}</ref>

===Propulsion===

Traditional [[internal combustion]] and [[jet engine]]s remain in use for drones requiring long range. However, for shorter-range missions electric power has almost entirely taken over. The distance record for a UAV (built from balsa wood and mylar skin) across the North Atlantic Ocean is held by a gasoline model airplane or UAV. Manard Hill "in 2003 when one of his creations flew 1,882 miles across the Atlantic Ocean on less than a gallon of fuel" holds this record.<ref>{{Cite news|url=https://www.washingtonpost.com/local/obituaries/model-airplane-history-maker-maynard-hill-dies-at-the-age-of-85/2011/06/08/AGcnyQNH_story.html|title=Model airplane history-maker Maynard Hill dies at the age of 85|newspaper=[[The Washington Post]]|access-date=17 May 2018|archive-date=4 July 2018|archive-url=https://web.archive.org/web/20180704034821/https://www.washingtonpost.com/local/obituaries/model-airplane-history-maker-maynard-hill-dies-at-the-age-of-85/2011/06/08/AGcnyQNH_story.html|url-status=live}}</ref>

Besides the traditional piston engine, the [[Wankel rotary engine]] is used by some drones. This type offers high power output for lower weight, with quieter and more vibration-free running. Claims have also been made for improved reliability and greater range.{{citation needed|date=May 2021|reason=not cited elsewhere}}

Small drones mostly use [[Lithium polymer battery|lithium-polymer batteries]] (Li-Po), while some larger vehicles have adopted the [[hydrogen fuel cell]].<ref>Al, S.; Xie, Y.; Malandrakis, K.; Lopez, M.; Tsourdos, A.; Ieee. Development of a Fuel Cell Hybrid-Powered Unmanned Aerial Vehicle. In 2016 24th Mediterranean Conference on Control and Automation, Mediterranean Conference on Control and Automation, Ieee, 2016; pp 1242-1247. <Go to ISI>://WOS:000391154900205</ref><ref>Baldic, J.; Osenar, P.; Lauder, N.; Launie, P. Fuel Cell Systems for Long Duration Electric UAVs and UGVs. In Defense Transformation and Net-Centric Systems 2010, Suresh, R. Ed.; Proceedings of SPIE-The International Society for Optical Engineering, Vol. 7707; Spie-Int Soc Optical Engineering, 2010;   770703. 10.1117/12.851779. <Go to ISI>://WOS:000285718300002.</ref><ref name="auto">Chu, D.; Jiang, R.; Dunbar, Z.; Grew, K.; McClure, J. Fuel Cell Powered Small Unmanned Aerial Systems (UASs) For Extended Endurance Flights. In Unmanned Systems Technology Xvii, Karlsen, R. E., Gage, D. W., Shoemaker, C. M., Gerhart, G. R. Eds.; Proceedings of SPIE, Vol. 9468; Spie-Int Soc Optical Engineering, 2015;   94680e; 10.1117/12.2087336. <Go to ISI>://WOS:000357636900011.</ref> [[Hydrogen]]-fueled [[proton-exchange membrane fuel cell]]s for UAVs have the advantages of longer flight duration than rechargeable [[lithium-ion batteries]], of lower [[total cost of ownership]] than primary [[lithium metal batteries]] and of better stealth than [[heat engines]].<ref>Nefedkin, S. I.; Klimova, M. A.; Glasov, V. S.; Pavlov, V. I.; Tolmachev, Y. V. Effect of the corrugated bipolar plate design on the self-humidification of a high power density PEMFC stack for UAVs. Fuel Cells 2021, 21 (3), 234-253,  10.1002/fuce.202000163. 
https://onlinelibrary.wiley.com/doi/10.1002/fuce.202000163.</ref>

The energy density of modern Li-Po batteries is far less than gasoline or hydrogen. However electric motors are cheaper, lighter and quieter. Complex multi-engine, multi-propeller installations are under development with the goal of improving aerodynamic and propulsive efficiency. For such complex power installations, [[Battery eliminator circuit|battery elimination circuitry]] (BEC) may be used to centralize power distribution and minimize heating, under the control of a [[Microcontroller|microcontroller unit]] (MCU).

=== Ornithopters – wing propulsion ===
Flapping-wing [[ornithopter]]s, imitating birds or insects, have been flown as [[Micro air vehicle|microUAVs]]. Their inherent stealth recommends them for spy missions.

Sub-1g microUAVs inspired by flies, albeit using a power tether, have been able to "land" on vertical surfaces.<ref>{{Citation |url=https://micro.seas.harvard.edu/papers/BB14_Chirarattananon.pdf |title=Adaptive control of a millimeter-scale flapping-wing robot |date=22 May 2014 |last1=Chirarattananon |first1=Pakpong |first2=Kevin Y |last2=Ma |first3=J |last3=Wood |journal=Bioinspiration & Biomimetics |doi=10.1088/1748-3182/9/2/025004 |pmid=24855052 |volume=9 |issue=2 |pages=025004 |bibcode=2014BiBi....9b5004C |archive-url=https://web.archive.org/web/20160416223803/http://micro.seas.harvard.edu/papers/BB14_Chirarattananon.pdf |archive-date=16 April 2016 |citeseerx=10.1.1.650.3728 |s2cid=12799012 }}</ref> Other projects mimic the flight of beetles and other insects.<ref>{{cite web|url=https://www.telegraph.co.uk/science/2016/03/29/giant-remote-controlled-beetles-could-replace-drones/|archive-url=https://web.archive.org/web/20160401144132/http://www.telegraph.co.uk/science/2016/03/29/giant-remote-controlled-beetles-could-replace-drones/|archive-date=1 April 2016|title=Giant remote-controlled beetles and 'biobot' insects could replace drones|author1=Sarah Knapton |date=29 March 2016|work=[[The Daily Telegraph|The Telegraph]]}}</ref>