I've read that by the end of World War I they had both contact and timed fuses(fuzes?), so in the case of a timed fuse (early in the war?), the bomb would just explode early, but what of the contact fuse? Would it eventually land and then explode?

I reckoned that if the contact fuse was at the nose a strong wind (or some other major attitude change) would cause the bomb to fall 'goofy' so it would just land without incident. However, I've also read that special fuses were created that armed based on sudden motion or change of direction, in which case you get roughly the same result as the timed fuse -- it would trip early or late and detonate too early or too late.

Are these valid assessments or am I missing something?

Thanks for any insights!

  • I think you may be confusing the term "aerial bomb" (which is a bomb dropped from the air) with "air burst" (which is an explosive designed to explode before hitting the ground). There's no such thing as a "contact air burst fuze". See en.wikipedia.org/wiki/Artillery_fuze#Airburst_fuzes
    – Comintern
    Commented Jun 30, 2014 at 1:18
  • You need to clarify your question. What exactly are you asking? Commented Jun 30, 2014 at 16:31
  • Voted to close: Big stretch to call this History - closer to physics and pyrotechnical/explosives engineering; if it is History, it's trivia.
    – user2590
    Commented Jul 6, 2014 at 22:55

4 Answers 4


This is not really a history question, but anyway...

I presume we are talking about shells here, not bombs. You may want to read "High Explosive Shells" By Percy E. Barbour, E. A. Suverkrop (1915) which you can find on Google Books.

Shells can (and did) have dual fuzes so that the shell would explode if it hit something before timer expired. There are many different types of possible fuzing arrangements with widely different outcomes. In World War I, the preferred fuze was a timed fuze so that the shell would burst in the air above the enemy.


According to "Birth of a Legend. The Bomber Mafia and the Y1B-17" by Capt Arthur H. Wagner, USCG(ret.) and Lt Col Leon E. Braxt, a Bulgarian Air Force pilot suggested the use of aircraft for bombing during the First Balkan War in 1912.

Subsequently, Captain Simeon Petrov developed the idea and created a number of prototypes. After a number of iterations the final design had an increased payload, an X-Shaped tail, improved aerodynamics and an impact fuse.

Furthermore, the book states that copies of the plans were later sold to Germany, was codenamed Chataldzha, and remained in mass production until the end of WW1.

The paragraph containing this information can be found here (Google Books).

While this doesn't speak for the other combatant nations in WW1, I can't imagine that the technology was that different.


In WWII, with better targeting equipment, bombs dropped on Japan from high altitude by B-29s generally missed their targets because of erratic winds. General Curtis LeMay took over command of the Pacific bombing forces and ordered the bombers to come in lower to correct the problem. See http://www.usaaf.net/ww2/hittinghome/hittinghomepg9.htm

  • This would be improved with citations/evidence of research.
    – MCW
    Commented Jul 3, 2014 at 10:03

I had always understood that bombs with a timed fuse were designed to detonate at a pre-set period after impact whereas you seem to be suggesting they would detonate a preset period after release.

The timer was chemical rather than mechanical and was designed to be triggered the moment the bomb first hit the surface of it's target (say the roof of a building, or the earth above a bunker). The delay would allow the inertia of the bomb to carry it through the roof and maybe a couple of floors before detonating on the ground floor and hopefully destroying the whole building. A bomb that hits a roof and detonates immediately is mostly likely to only destroy the roof and maybe the top floor, a bomb that detonates on the ground floor may well knock out all the walls a cause a complete collapse. Similarly a bomb that detonates on the surface immediately above a bunker might not destroy it, but a bomb whose inertia has carried it a few feet into the ground before detonating is likely to have a much more damaging effect.

Sorry, I can't actually find any references for this. I've always assumed that this was how bombs worked, I could be wrong (and frequently am)

  • What you're describing is usually called a "delayed-action fuse".
    – Mark
    Commented Oct 27, 2018 at 1:28

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