Editing Pusher configuration (section)

====Structural and weight considerations====
[[Image:Saab J 21A-3.jpg|thumb|[[SAAB 21|SAAB J 21]] fighter, with the pusher propeller mounted between two fuselage booms]]
A pusher design with an empennage behind the propeller is structurally more complex than a similar tractor type. The increased weight and [[Drag (physics)|drag]] degrades performance compared with a similar tractor type. Modern aerodynamic knowledge and construction methods may reduce but never eliminate the difference. A remote or buried engine requires a drive shaft and associated bearings, supports, and torsional vibration control, and adds weight and complexity.<ref name= "Technicalities">{{cite web |first= Peter|last= Garrison|title= Technicalities|date= 29 June 2009|publisher= Flying|url= http://www.flyingmag.com/technicalities-2|access-date= 12 October 2011|url-status= live|archive-url= https://web.archive.org/web/20120329185615/http://www.flyingmag.com/technicalities-2|archive-date= 29 March 2012}}</ref><ref>{{cite magazine |last= Hassenaur|first= Donald P.|date= 1 January 1996|title= Propeller Drive Systems and Torsional Vibration|pages= 167–172|magazine= Alternative Engines|volume= 1|others= compiled by Mick Myal|location= Phoenix, Arizona|publisher= Fiesta Publishing|isbn= 9780964361324}}</ref>