Editing Slipstream (section)

== Spiral slipstream <!-- Other articles link here. --> ==

'''Spiral slipstream''', also known as '''propwash''', ''prop wash'', or ''spiraling slipstream'', is a [[spiral]]-shaped slipstream formed behind a rotating [[Propeller (aircraft)|propeller]] on an [[aircraft]]. The most noticeable effect resulting from the formation of a spiral slipstream is the tendency to [[Roll, pitch, and yaw|yaw]] nose-left at low speed and full [[throttle]] (in centerline [[Tractor configuration|tractor]] aircraft with a clockwise-rotating propeller.) This effect is caused by the slipstream acting upon the tail [[vertical stabilizer|fin]] of the aircraft: The slipstream causes the air to rotate around the longitudinal axis of the aircraft, and this air flow exerts a force on the tail fin, pushing it to the right. To counteract this, some aircraft have the front of the fin (vertical stabilizer) slightly offset from the centreline so as to provide an opposing force that cancels out the one produced by the slipstream, albeit only at one particular (usually cruising) speed, an example being the [[Hawker Hurricane]] fighter from [[World War II]].

Propeller slipstream causes increased lift by increasing the airspeed over part of the wings. It also reduces the [[Stall (fluid dynamics)#Stall speeds|stall speed]] of the aircraft by energizing the flow over the wings.<ref name="Davies">{{cite book |last1=Davies |first1=David P. |title=Handling the Big Jets: An Explanation of the Significant Differences in Flying Qualities Between Jet Transport Aeroplanes and Piston Engined Transport Aeroplanes, Together with Some Other Aspects of Jet Transport Handling |date=1971 |publisher=Air Registration Board |url=https://books.google.com/books?id=TKZTAAAAMAAJ |language=en |isbn=0903083019 |edition=3rd}}</ref>{{rp|61}}