Editing Self-destruct (section)

===Anti-aircraft cannon shells===

Since [[anti-aircraft weapon]]s are used in the [[home front]] or in the rear of friendly forces anti-aircraft cannon [[Shell (projectile)|shells]] are often equipped with self-destruct mechanisms to prevent missed shots from falling down and causing damage to friendly targets. Different self-destruct types exists: in [[tracer ammunition]] the burning tracer material can trigger a self-destruct fuse at the end. Other self-destruct types are mechanical where a spring is held back by the [[centrifugal force]] of the rotating projectile; as the drag slows down the rotation the force is eventually no longer able to prevent the spring from triggering the self-destruct fuse. Heavy anti-aircraft cannons typically fired [[time fuse]]d shells which did not need a separate self-destruct since they were intended to detonate in the air after a set time.<ref>{{Cite book
 | last1 = Vehviläinen
 | first1 = Raimo
 | last2 = Lappi
 | first2 = Ahti
 | last3 = Palokangas
 | first3 = Markku
 | title = Itsenäisen Suomen ilmatorjuntatykit 1917-2000
 | trans-title = Anti-aircraft cannons of independent Finland 1917-2000
 | chapter = 2. Ilmatorjuntatykistön teoriaa ja käytöntöä
 | trans-chapter = 2. Theory and practice of anti-aircraft artillery
 | language = Finnish
  | publisher = Sotamuseo
 | year = 2005
 | location = Helsinki
 | page = 42
 | url =
 | doi =
 | id =
 | isbn = 952-91-8449-2}}</ref>