Static wick
{{Short description|Aircraft component to discharge static electricity}}
{{More citations needed|date=December 2009}}Image:easyjet a319-100 g-ezbv winglet arp.jpg and aileron of an EasyJet Airbus A319-100]]
Static wicks, also called static dischargers or static discharge wicks, are devices used to remove static electricity from aircraft in flight. They take the form of small sticks pointing backwards from the wings, and are fitted on almost all civilian aircraft.{{Cite web|title=This Is What Those Skinny Metal Rods Sticking Off Of A Plane Are For|url=https://jalopnik.com/this-is-what-those-skinny-metal-rods-sticking-off-of-a-1848436120|access-date=2022-01-29|website=Jalopnik|language=en-us}}
Function
Precipitation static is an electrical charge on an airplane caused by flying through rain, snow storms, ice, or dust particles. Charge also accumulates through friction between the aircraft hull and the air. When the aircraft charge is great enough, it discharges into the surrounding air. Without static dischargers, the charge discharges in large batches through pointed aircraft extremities, such as antennas, wing tips, vertical and horizontal stabilizers, and other protrusions. The discharge creates a broad-band radio frequency noise from DC to 1000 MHz, which can affect aircraft communication.{{Citation needed|date=January 2022}}
To control this discharge, so as to allow the continuous operation of navigation and radio communication systems, static wicks are installed on the trailing edges of aircraft. These include (electrically grounded) ailerons, elevators, rudder, wing, horizontal and vertical stabilizer tips. Static wicks are high electrical resistance (6–200 megaohm) devices with a lower corona voltage and sharper points than the surrounding aircraft structure.{{Citation needed|date=January 2022}} This means that the corona discharge into the atmosphere flows through them, and occurs gradually.{{cite web |url= http://www.flyingmag.com/technique/tip-week/check-your-wicks |title= Check Your Wicks |author= Pia Bergqvist |work= Flying Magazine |date= March 11, 2013 |accessdate=March 13, 2017}}
Static wicks are not lightning arresters and do not affect the likelihood of an aircraft being struck by lightning. They will not function if they are not properly bonded to the aircraft. There must be a conductive path from all parts of the airplane to the dischargers, otherwise they will be useless. Access panels, doors, cowls, navigation lights, antenna mounting hardware, control surfaces, etc., can create static noise if they cannot discharge through the static wick.{{Citation needed|date=January 2022}}
History
File:Static discharger with plastic guards.jpg
Static dischargers were first proposed in a patent application by Howard Dudley Blanchard in 1920.{{cite web |last1=Blanchard |first1=Howard Dudley |title=Aircraft |url=http://www.aeroelectric.com/Reference_Docs/Patents/Static_Dissipation/1419261_Static_Dissipation.pdf |website=Aeroelectric |access-date=20 April 2025}} At this time most aircraft were constructed from cloth and wood, and rigid body airships were widely used. Therefore, a method of gradually discharging static accumulation was necessary since static discharge on these craft could cause serious damage and start fires. Static discharge is the likely cause of the Hindenburg disaster.{{Citation needed|date=April 2025}}
The first static wicks were developed by a joint Army-Navy team led by Dr. Ross Gunn of the Naval Research Laboratory and fitted onto military aircraft during World War II. They were shown to be effective even in extreme weather conditions in 1946 by a United States Army Air Corps team led by Capt. Ernest Lynn Cleveland.{{Citation needed|date=January 2022}}
Dayton Granger, an inventor from Florida, received a patent on static wicks in 1950.{{Cite web|title=This Is What Those Skinny Metal Rods Sticking Off Of A Plane Are For|url=https://jalopnik.com/this-is-what-those-skinny-metal-rods-sticking-off-of-a-1848436120|access-date=2022-01-29|website=Jalopnik|language=en-us}}