I have no major problem with effectiveness of night bombing against ground targets. It is super effective only against overstacked airfields with no night CAP.
However, I have a very big problem with effectiveness of bomber defensive fire in the night, mostly relevant to 4Es. If they are strong but manageable during the day, during the night they break the air combat model in half. Here's the resuls of 4Es flying against mainly my most elite squadrons for a 2-day turn:
Here's the combat reports:
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Night Air attack on Milne Bay , at 101,133
Weather in hex: Partial cloud
Raid detected at 26 NM, estimated altitude 9,000 feet.
Estimated time to target is 8 minutes
Japanese aircraft
A6M2-N Rufe x 8
A6M3 Zero x 23
A6M3a Zero x 13
Allied aircraft
B-17E Fortress x 3
B-17F Fortress x 4
B-24D Liberator x 7
Japanese aircraft losses
A6M2-N Rufe: 1 destroyed
A6M3a Zero: 5 damaged
A6M3a Zero: 1 destroyed on ground
G4M1 Betty: 1 destroyed on ground
Allied aircraft losses
B-24D Liberator: 1 damaged
Airbase supply hits 2
Runway hits 9
Aircraft Attacking:
4 x B-17F Fortress bombing from 8000 feet
Airfield Attack: 8 x 500 lb GP Bomb
3 x B-17E Fortress bombing from 8000 feet
Airfield Attack: 8 x 500 lb GP Bomb
4 x B-24D Liberator bombing from 8000 feet
Airfield Attack: 10 x 500 lb GP Bomb
3 x B-24D Liberator bombing from 8000 feet
Airfield Attack: 10 x 500 lb GP Bomb
CAP engaged:
Chitose Ku S-1 with A6M3a Zero (8 airborne, 0 on standby, 0 scrambling)
8 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
3rd Ku S-1 with A6M3 Zero (7 airborne, 16 on standby, 0 scrambling)
7 plane(s) intercepting now.
Group patrol altitude is 20000 , scrambling fighters between 8000 and 20000.
Time for all group planes to reach interception is 10 minutes
5th Ku S-1 with A6M2-N Rufe (2 airborne, 6 on standby, 0 scrambling)
2 plane(s) intercepting now.
Group patrol altitude is 15000 , scrambling fighters between 6000 and 10000.
Time for all group planes to reach interception is 8 minutes
12th Ku S-1 with A6M3a Zero (5 airborne, 0 on standby, 0 scrambling)
5 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
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Night Air attack on Milne Bay , at 101,133
Weather in hex: Partial cloud
Raid detected at 26 NM, estimated altitude 11,000 feet.
Estimated time to target is 8 minutes
Japanese aircraft
A6M2-N Rufe x 6
A6M3 Zero x 14
A6M3a Zero x 13
Allied aircraft
B-24D Liberator x 6
Japanese aircraft losses
A6M2-N Rufe: 1 destroyed
A6M3 Zero: 1 destroyed
Allied aircraft losses
B-24D Liberator: 1 damaged
Aircraft Attacking:
6 x B-24D Liberator bombing from 8000 feet
Airfield Attack: 10 x 500 lb GP Bomb
CAP engaged:
Chitose Ku S-1 with A6M3a Zero (8 airborne, 0 on standby, 0 scrambling)
8 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
3rd Ku S-1 with A6M3 Zero (14 airborne, 0 on standby, 0 scrambling)
14 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
12th Ku S-1 with A6M3a Zero (5 airborne, 0 on standby, 0 scrambling)
5 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
5th Ku S-1 with A6M2-N Rufe (6 airborne, 0 on standby, 0 scrambling)
6 plane(s) intercepting now.
Group patrol altitude is 15000
Raid is overhead
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Night Air attack on Milne Bay , at 101,133
Weather in hex: Light rain
Raid detected at 39 NM, estimated altitude 13,000 feet.
Estimated time to target is 13 minutes
Japanese aircraft
A6M2-N Rufe x 6
A6M3 Zero x 15
A6M3a Zero x 36
Allied aircraft
B-17E Fortress x 8
B-17F Fortress x 6
B-24D Liberator x 3
Japanese aircraft losses
A6M3 Zero: 2 destroyed
A6M3a Zero: 3 destroyed, 2 damaged
A6M3a Zero: 1 destroyed on ground
Allied aircraft losses
B-17E Fortress: 1 destroyed, 1 damaged
B-17F Fortress: 1 damaged
B-24D Liberator: 2 damaged
Runway hits 2
Aircraft Attacking:
6 x B-17F Fortress bombing from 8000 feet
Airfield Attack: 8 x 500 lb GP Bomb
7 x B-17E Fortress bombing from 8000 feet
Airfield Attack: 8 x 500 lb GP Bomb
3 x B-24D Liberator bombing from 8000 feet
Airfield Attack: 10 x 500 lb GP Bomb
CAP engaged:
Chitose Ku S-1 with A6M3a Zero (6 airborne, 0 on standby, 0 scrambling)
6 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
Tainan Ku S-1 with A6M3a Zero (6 airborne, 18 on standby, 0 scrambling)
6 plane(s) intercepting now.
Group patrol altitude is 20000 , scrambling fighters between 2000 and 20000.
Time for all group planes to reach interception is 5 minutes
3rd Ku S-1 with A6M3 Zero (3 airborne, 12 on standby, 0 scrambling)
3 plane(s) intercepting now.
Group patrol altitude is 20000 , scrambling fighters between 6000 and 20000.
Time for all group planes to reach interception is 9 minutes
5th Ku S-1 with A6M2-N Rufe (2 airborne, 4 on standby, 0 scrambling)
2 plane(s) intercepting now.
Group patrol altitude is 15000 , scrambling fighters to 15000.
Time for all group planes to reach interception is 10 minutes
12th Ku S-1 with A6M3a Zero (6 airborne, 0 on standby, 0 scrambling)
6 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
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Night Air attack on Milne Bay , at 101,133
Weather in hex: Light rain
Raid detected at 34 NM, estimated altitude 8,000 feet.
Estimated time to target is 11 minutes
Japanese aircraft
A6M2-N Rufe x 5
A6M3 Zero x 8
A6M3a Zero x 22
Allied aircraft
B-24D Liberator x 4
Japanese aircraft losses
A6M3a Zero: 2 destroyed
Allied aircraft losses
B-24D Liberator: 2 damaged
Aircraft Attacking:
4 x B-24D Liberator bombing from 8000 feet
Airfield Attack: 10 x 500 lb GP Bomb
CAP engaged:
Chitose Ku S-1 with A6M3a Zero (6 airborne, 0 on standby, 0 scrambling)
6 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
Tainan Ku S-1 with A6M3a Zero (13 airborne, 0 on standby, 0 scrambling)
13 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
3rd Ku S-1 with A6M3 Zero (8 airborne, 0 on standby, 0 scrambling)
8 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
5th Ku S-1 with A6M2-N Rufe (1 airborne, 0 on standby, 0 scrambling)
1 plane(s) intercepting now.
4 plane(s) not yet engaged, 0 being recalled, 0 out of immediate contact.
Group patrol altitude is 15000 , scrambling fighters to 15000.
Time for all group planes to reach interception is 10 minutes
12th Ku S-1 with A6M3a Zero (3 airborne, 0 on standby, 0 scrambling)
3 plane(s) intercepting now.
Group patrol altitude is 20000
Raid is overhead
This is pretty much a standard result. I'm forced to make strategic concessions because 4E night bombing cannot be countered in any way, shape or form, as long as your opponent is careful about picking his airfields. Ki-45s are wiped out almost as easily, if you wonder. I also estimate that a 4E force of the size shown above will shut down a level 5 airfield with 100 engineers + 3 vehicles in 6-8 days unless it faces CAP, so just dispersing and accepting losses on ground is not possible.