The new bomb fuzing needs to be an option.

[Letum]

Time we ahd some actual data with a source...

My source for this data is "Ordnance Pamphlet 1548" Bomb Fuse Data 1945 October 5th.

Ordnance Pamphlet 1548 contains a summary of pertinent information concerning all bomb fuzes of restricted and non restricted classifications now in use by the US Navy or Army

In this document arming delay is measured by "Air travel to Arm".

This gives an average figure (unless otherwise noted) for the air travel, along the trajectory of the bomb for which it is designed.

I will give both the 'air travel to arm' and vertical fall required to reach that speed at a TAS of 100, 200, 300 and 400 Knots with a dive angle of 0 degrees (the document provides a handy conversion chart). I won't give data on fuzes that do not apply to IL2, but I will list them.

Navy Fuzes

Fuze: AN-mk 219
Type: Instant impact
Bombs: GP bombs from 100lb to 1000lb
Air Travel to Arm: 1000 ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - 440 ft
200kn - 140ft
300kn - 60 ft
400kn - 40 ft


Fuze: mk 221
Type: Impact, 0.01 second delay
Bombs: GP bombs from 100lb to 1000lb
Air Travel to Arm: 850 - 1100 ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - 350-500 ft
200kn - 95-160 ft
300kn - 40-75 ft
400kn - 23-40 ft


Fuze: mk 223
Type: Impact/inertia, 0.01 second delay
Bombs: GP bombs from 100lb to 1000lb
Air Travel to Arm: 850 - 1100 ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - 350-500 ft
200kn - 95-160 ft
300kn - 40-75 ft
400kn - 23-40 ft


Fuze: mk 227
Type: Anti-aircraft bomb

Fuze: mk 228
Type: Impact/inertia, 0.08 second delay
Bombs: GP bombs from 1000lb to 1600lb
Air Travel to Arm: 1100 ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - 500 ft
200kn - 160 ft
300kn - 75 ft
400kn - 40 ft


Fuze: mk 224, 229, 230, 231, 234, 240
Type: hydrostatic

Fuze: mk 235 & 236
Type: 2 - 30 hour delay

Fuze: mk 239
Type: Impact, 0.01 second delay
Bombs: All GP bombs except navy 100lb
Air Travel to Arm: 850 - 1100 ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - 350-500 ft
200kn - 95-160 ft
300kn - 40-75 ft
400kn - 23-40 ft


Fuze: mk 243
Type: Water discriminating

Fuze: mk 244
Type: Impact, 4 second delay
Bombs: All GP bombs except navy 100lb
Air Travel to Arm: 450 ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - 110 ft
200kn - 25 ft
300kn - <20 ft
400kn - <20 ft


Army Fuzes

Fuze: AN M100,101,102
Type: Impact/inertia, non-delay up to 0.24 second delay
Bombs: GP bombs from 100lb to 4000lb
Air Travel to Arm: 2000ft or 445ft
Vertical fall required to arm with a dive angle of 0 degrees: (445ft version only)
100kn - 100 ft
200kn - 25 ft
300kn - <20 ft
400kn - <20 ft

Fuze: AN M103
Type: Impact, non-delay up to 0.1 second delay
Bombs: All GP bombs - Restricted to non-naval use
Air Travel to Arm: 1140ft with delay, 1710ft without delay or 510ft with delay, 765ft without delay
Vertical fall required to arm with a dive angle of 0 degrees: (510 version only)
100kn - 140 ft
200kn - 37 ft
300kn - <20 ft
400kn - <20 ft

Fuze: AN M104, 120, 170
Type: Para-Frag

Fuze: AN M106
Type: Impact, delay 4-11 seconds
Bombs: All GP bombs - Restricted to non-naval use
Air Travel to Arm: None. Armed by safety wire

Fuze: M106, 147, 152, 153
Bombs: target ID and incendiary

Fuze: M110
Bombs: 20lb

Fuze: M11, 146
Bombs: flare

Fuze: m112,113,114
Type: Impact/inertia with 4-15 second delay
Bombs: All GP bombs
Air Travel to Arm: 100ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - 10 ft
200kn - < 10 ft
300kn - < 10 ft
400kn - < 10 ft

Fuze: m115,116,117
Type: Impact/inertia with 4-15 second delay
Bombs: All GP bombs
Air Travel to Arm: 450-650ft
Vertical fall required to arm with a dive angle of 0 degrees: (500ft ATtA)
100kn - 130 ft
200kn - 30 ft
300kn - < 20 ft
400kn - < 20 ft

Fuze: M123,124,125, 132, 133
Type: Long Delay

Fuze: M126, 127, 128, 158, 159
Bombs: Chemical

Fuze: M129, 130, 131
Bombs: Butterfly Bomb

Fuze: m135, 136, 137
Type: Impact or 5-92 second delay
Bombs: All GP bombs
Air Travel to Arm: 1300ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - over 500 ft
200kn - 180 ft
300kn - 80 ft
400kn - 43 ft

Fuze: m139, 140
Type: Impact or 0.01 second delay
Bombs: All GP bombs
Air Travel to Arm: 510ft with delay, 765ft without delay
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - 130 or 265 ft
200kn - 30 or 68 ft
300kn - < 20 or 28 ft
400kn - < 20 or 20 ft

Fuze: 142,145, 151, 155
Type: Cluster bomb

Fuze: 143
Type: Smoke bomb

Fuze: 148
Type: to fit captured Japanese bombs

Fuze: m149
Type: Impact or air pressure
Bombs: All GP bombs
Air Travel to Arm: 250ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - 25 ft
200kn - < 20 ft
300kn - < 20 ft
400kn - < 20 ft

Fuze: 157
Type: Napalm

Fuze: m160, 161, 162
Type: Impact inertia, non delay or up to .24 second delay
Bombs: All GP bombs 100lb to 4000lb
Air Travel to Arm: 2000ft
Vertical fall required to arm with a dive angle of 0 degrees:
100kn - over 500 ft
200kn - ~400 ft
300kn - ~200 ft
400kn - ~140 ft

Fuze: m160, 161, 162
Type: Impact inertia, non delay
Bombs: All GP bombs
Air Travel to Arm: 1500ft or 2200ft
Vertical fall required to arm with a dive angle of 0 degrees: (1500ft)
100kn - over 500 ft
200kn - 300 ft
300kn - 140 ft
400kn - 80 ft

How does this data compare to IL2 4.10?

IL2's new bomb fuze system works like modern mechanical fuzes with governors on the arming vane.
They arm after 2.5 (or 2?) seconds, regardless of aircraft speed.

After a little testing in IL2 I found that this means you must be at or above 29.5m / 97ft for the bomb to detonate after it is released in level flight. This is regardless of speed.

The fuze in IL2 acts like many wartime fuzes do when they are dropped in level flight at 200knots TAS. At 200knots it acts as if it where a fuze with a 850 foot air travel to arm distance

There are, however some fuzes that armed faster and some fuzes that armed slower than this at 200knots.

Below 200 knots IL2's bombs arm too quickly compared to most second war fuzes and above 200 knots IL2's bombs arm too slowly compared to most second war.



Facts end here, opinion starts below.

It's unreasonable for IL2 to model all fuzes. There are too many for US bombs alone and US bombs are only a fraction of the bombs ingame. We need to use ball-park figures for IL2's bombs.

From the data above, we can see that IL2's current arming delay is well within the ball park for speeds between 100 knots to about 250 knots. Above these speeds IL2's bombs start to leave the ball-park a little as the two seconds become too long.

The B25 has a top speed of about 200 knots and the A20 has a top speed of about 250 knots. At these speeds IL2's bomb arming delay compares well to real data for US bombs.
The P47's top speed of about 300 knots means the bomb arming delay is going to be too long, even more so if it is in a dive.

Ideally, the arming delay would be a result of the distance the bomb has traveled, but that kind of data may not be easy to calculate for the game.
If you had to have a time based arming delay, IL2 4.10's delay is about the best you could pick. For most speeds it's about right, for some speeds it's too short, for other too long, but it is about in the middle.
Certainly a huge improvement on having no delay.



edit: I forgot to mention about what fuzes where most common. I have no idea what fuzes where most common.