Jesus nut
Encyclopedia
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
s, such as the UH-1 Iroquois
UH-1 Iroquois
The Bell UH-1 Iroquois is a military helicopter powered by a single, turboshaft engine, with a two-bladed main rotor and tail rotor. The helicopter was developed by Bell Helicopter to meet the United States Army's requirement for a medical evacuation and utility helicopter in 1952, and first flew...
helicopter. The term may have been coined by American soldiers in Vietnam
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
; the Vietnam War was the first war to feature large numbers of soldiers riding in helicopters. Other sources suppose that the term may be coined as early as by Igor Sikorsky
Igor Sikorsky
Igor Sikorsky , born Igor Ivanovich Sikorsky was a Russian American pioneer of aviation in both helicopters and fixed-wing aircraft...
, a pioneer of rotor wing aircraft, who was a deeply religious person http://texino.blogspot.com/2008/07/jesus-nut.html.
The term may have come from the idea that, if the Jesus pin were to fail in flight, the helicopter would detach from the rotors and the only thing left for the crew to do would be to pray to Jesus
Jesus
Jesus of Nazareth , commonly referred to as Jesus Christ or simply as Jesus or Christ, is the central figure of Christianity...
. In addition, a person must have faith in the Jesus bolt to do its intended job without failure. Real examples of the Jesus pin failing are few and far between. However the pin must be checked before the flight http://www.tc.gc.ca/civilaviation/publications/tp3658/1-02/001.htm. Some more recent helicopter systems do not have a Jesus nut.
More recently, it has come to be a generic engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
term referring to any single component of a system whose failure would cause catastrophic failure
Catastrophic failure
A catastrophic failure is a sudden and total failure of some system from which recovery is impossible. Catastrophic failures often lead to cascading systems failure....
of the whole system.
In literature the term Jesus Nut was used in Chickenhawk
Chickenhawk (book)
Chickenhawk is Robert Mason's narrative of his experiences as a UH-1 Iroquois helicopter pilot during the Vietnam War. The book chronicles his enlistment, flight training, deployment to and experiences in Vietnam, and his experiences after returning from the war.- Writing, Publishing, and Reaction...
by Robert Mason
Robert Mason
Robert Mason may refer to:*Robert Mason *Robert Mason , Member of Parliament for Wansbeck 1918–1922...
, a narrative about his experiences in the Vietnam War.
The Rattler/Firebird Association is a Vietnam War veterans organisation. It awards a chrome plated Jesus nut to the member who traveled the longest distance to their reunions. http://rattler-firebird.org/association/reunions/JesusNut.php
Mountain bikers often use the term to describe the screw that holds the rear wheel pivot bar in place on a rear suspension bike. This bar holds the back suspension onto the frame of the bike. If the screw falls out, the pivot bar tends to slide out, leading to catastrophic rear-wheel failure, ending in unavoidable loss of the back wheel. Since the pivot bar will only come out under heavy vibrations, it tends to fail at high speed, therefore leading to serious injury.
Another use for the term is found in rock climbing
Rock climbing
Rock climbing also lightly called 'The Gravity Game', is a sport in which participants climb up, down or across natural rock formations or artificial rock walls. The goal is to reach the summit of a formation or the endpoint of a pre-defined route without falling...
, in which it refers to the first piece of protection placed on a pitch
Pitch (vertical space)
-Climbing:In rock climbing and ice climbing, a pitch is a steep section of a route that requires a rope between two belays, as part of a climbing system...
. This piece must be placed to resist an outward pull as well as a downward pull in order to avoid the possibility of a "zipper", in which the outward pull on the rope from the belayer arresting a falling climber pulls protection pieces from the bottom up. In addition, the Jesus Nut prevents the possibility of a factor two fall
Fall factor
In climbing, using a dynamic rope, the fall factor f is the ratio of the height h a climber falls before the climber's rope begins to stretch and the rope length L available to absorb the energy of the fall....
onto the belay anchor
Anchor (climbing)
In rock climbing, an anchor can be any way of attaching the climber, the rope, or a load to rock, ice, steep dirt, or a building by either permanent or temporary means...
.
Jesus nut is also used in reference to the nut on the front of the recoil mechanism on some artillery pieces. Should this nut fail, the gun tube will come out of battery upon firing, potentially leading to death for the gun crew.
A derivative term used in radio-controlled helicopter
Radio-controlled helicopter
Radio-controlled helicopters are model aircraft which are distinct from RC airplanes because of the differences in construction, aerodynamics, and flight training...
s is the "Jesus Bolt", which refers to a bolt whose function is analogous to the Jesus nut in a full size helicopter.