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Bomb fuze timings


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The SC 250 and SC 500 had the 25/A/B/C fuze type as seen in the diagram below. This is the general purpose type electric land fuze. Starting mid 1943 only type C was used, so in late war scenarios only this type is of importance. Type C differs to type B only in temperature sensitivity, as the latter had increased fuze arm times at below -20°C. The C type is temperature stable up to -50°C. The explanation of the differences can be seen in the second picture which is a development flow chart of the fuzes.








There are two relevant factors in fuze settings to arming, dropping and exploding the bomb. First there is the arming delay and second there is the firing delay.


The fuze has two settings, Zündstellung I & Zündstellung II which have to be ground adjusted for the Bf 109 or FW 190. You can only set the fuze to either Zündstellung I or Zündstellung II on the ground, there is no changing it in the air. It is set by a small screw, which can be seen in the following photograph.




Zündstellung I means that by setting the ZSK 244 to m.V. in either waagerecht or sturz the firing delay is set to 0.08 s. Zündstellung II sets the m.V. firing delay for both waagerecht or sturz to 14 s. For both Zündstellung I & II the o.V setting in waagerecht or sturz has no firing delay. These are the delay timings after which an armed and impacted bomb will detonate.


Type 25B and C differ to some extend in fuze arming delay times, but are mostly similiar. The only difference being Zündstellung I waagerecht o.V. & m.V. which can be read with pretty good accuracy from the fourth picture below. As can be seen in the third picture the arming times for Zündstellung I & II are the same. But due to the nature of the wiring only either m.V. or Vz. timings can be used exclusively.


Now to the arming delay of the 25C fuze:


Zündstellung I

waagerecht o.V. 3 -6 s (second number read from the graph of picture four)

waagerecht m.V. 5.6 -11.6 s (second number read from the graph of picture four)

senkrecht o.V. 1.9 - 3.5 s

senkrecht m.V. 1.9 - 3.6 s


Zündstellung II

waagerecht o.V. 3 -6 s (second number read from the graph of picture four)

waagerecht m.V. 0.8 -1.5 s

senkrecht o.V. 1.9 - 3.5 s

senkrecht m.V. 0.4 - 0.7 s


Before the first number the fuze is 0% armed, the second number is the 100% arm time. If it impacts before the first timepoint it will not detonate. In between this time there is a partial arming window, so some bombs may detonate.

So in essence Zündstellung I is the "high altitude" fuze setting while Zündstellung II is the "low altitude" fuze setting.


The Bf 109 and FW 190 are neither level bombers, so Zündstellung II could be used in the sim as a standard. This allows either o.V. without delay or m.V. for a firing delay of 14 s. Then the Zündstellung II arming delays need to be programmed for each setting as shown above.







These are the original descriptions of the fuzes.








As a little bonus:


I noticed on Burning Skies a SC 250 bomb doesnt kill the ships. Take a look at the following. :music_whistling:



Edited by rel4y

Cougar, CH and Saitek PnP hall sensor kits + shift registers: https://forums.eagle.ru/showthread.php?t=220916


Shapeways store for DIY flight simming equipment and repair: https://www.shapeways.com/shops/rel4y-diy-joystick-flight-simming

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