Editing VTOL (section)

===Lift via Coandă effect===
{{Main|Coandă effect}}
Aircraft in which VTOL is achieved by exploiting the [[Coandă effect]] are capable of redirecting air much like [[thrust vectoring]], but rather than routing airflow through a duct, the airflow is simply routed along an existing surface, which is usually the body of the craft allowing less material and weight.

The [[Avro Canada VZ-9 Avrocar]], or simply the VZ-9, was a Canadian VTOL aircraft developed by [[Avro Canada|Avro Aircraft Ltd.]] which utilizes this phenomenon by blowing air into a central area, then it is directed down over the top surface, which is [[parabola|parabolic]] and resembles a bowed [[flying saucer]]. Due to the Coandă effect, the airflow is attracted to the nearest surface and continues to move along that surface despite the change in the surface's direction away from the airflow. The craft is designed to direct the airflow downward to provide lift.

Jetoptera announced a proposed line of aircraft based on what it called fluidic propulsion that employs the Coandă effect. The company claims an [[Oswald efficiency number]] of 1.45 for its boxwing design. Other claims include increased efficiency, 30% lower weight, reduced complexity, as much as 25 [[A-weighting|dBA]] lower (and atonal) noise, shorter wings, and scalability.<ref>{{Citation|title=Jetoptera's Bladeless Propulsion System|date=February 18, 2021|url=https://www.youtube.com/watch?v=bPZI6XoHi10| archive-url=https://ghostarchive.org/varchive/youtube/20211117/bPZI6XoHi10| archive-date=2021-11-17 | url-status=live|publisher=Electric Aviation|language=en|access-date=2021-04-29}}{{cbignore}}</ref><ref>{{Cite web|last=Blain|first=Loz|date=2021-04-28|title=Jetoptera VTOL aircraft design features "bladeless fans on steroids"|url=https://newatlas.com/aircraft/jetoptera-aircraft-propulsion-system/|url-status=live|access-date=2021-04-30|website=New Atlas|language=en-US |archive-date=2021-04-30 |archive-url=https://web.archive.org/web/20210430104212/https://newatlas.com/aircraft/jetoptera-aircraft-propulsion-system/ }}</ref> Jetoptera says its approach yields thrust augmentation ratios exceeding 2.0 and 50% fuel savings when compared to a [[turbofan]] in static or hovering conditions. Its efflux can be used for Upper Surface Blown architectures to boost the [[Lift Coefficient]] to values exceeding 8.0.