Decoding aircraft weapons values

[el cid again]

Aircraft weapons do not seem to use the same values that are used for surface combat. There, an automatic gun uses ten times shell weight for effect and the ROF = accuracy. [This is a variation of naval gunnery which uses shell weight for effect and ten times ROF = accuracy - this variation for high speed "machine cannon"]

But for aircraft weapons clearly some other system was used. Going back to old stock data, it became clear that the accuracy is purely a function of ROF - but a square root function. Thus

1100 ROF = 33 (sq root 33.166)
850 ROF = 29 (sq root 29.155)
750 ROF = 27 (sq root 27.386)
15 ROF = 4 (sq root 3.873)

In which case, clearly the idea used for machine cannon does not apply:
they are not multiplying by 10. IF they did,

.30 cal would be 1/5 (152 grains or 1/4.6 of a .50 cal round)
.50 cal would be 1 (711.5 grains at 7000 grains per pound times 10)
20 mm would be 3 (about 1/3 pound times 10 - .280 to .363 pound)
40 mm would be 20 (about 2 pounds times 10 - 1.92 to 2.06 pound)

But the game values are typically
.30 cal = 2
.50 cal = 3 or 4
20 mm = 4
23 mm = 5
30 mm = 5
37 mm = 4

Not based clearly on anything. But clearly the relative punch of a cannon is not represented well in this system. [All these guns have AP, explosive HE, and tracer rounds. I didn't realize there were explosive .30 cal, but it was standard issue.]

I am proposing to use the cube root of round weight for effect:

1 for .30 cal
2 for .50 cal
3 for 15 mm
7 for 20 mm
8 for 23 mm
10 for 30 mm
12 for 37 mm
13 for 40 mm
21 for 57 mm

I have added a 57mm to the Ki-102b - because it really had one! It also is the ONLY weapon with a range greater than 1 in this system. Although I just found a 75 mm US aircraft gun - I have not yet found what plane carried it - or if it was for use air to air or vs surface (as I suspect)?

[Monter_Trismegistos]

One version of B-25 had 75mm gun to kill ships... EDIT: B-25G

[witpqs]

I knew there was a 2E bomber with one, but couldn't remember which...

[el cid again]

One version of B-25 had 75mm gun to kill ships... EDIT: B-25G

Anyone want 75mm guns - or torpedoes - on US mediums that were designed to have them?

[Sardaukar]

Yes, I want B-25G.

[Nomad]

The only problem is that when you use them historically, you have to put them at 100' and they take huge morale hits.

[witpqs]

The code might be set up to force this - the P-39's only strafe with the 37mm cannon at low altitude.

Let's have 'em!

[el cid again]

The code might be set up to force this - the P-39's only strafe with the 37mm cannon at low altitude.

In fairness to the code, NOTHING can STRAFE EXCEPT at low altitude! If it is not at low altitude - it isn't strafing! In my games, I only allow strafing from very low altitude. I dont see how to strafe from several hundred feet. Go up in a light plane and take a look.

[witpqs]

Agreed, I was responding to the comment about historical use. The code requires it, in this case.

[Nomad]

What I was commenting on is that to use a B-25J with its 12 or so forward firing .50 Cals, you have to fly them at 100'. they often(always?) take a large morale hit. This will generally make them a lot less useful in the game than they were in real life. Adding a 75mm gun may or may not be useful. If they can only fly once every 14 or so days then why do it? ( I have had B-25J groups lose 40 morale on one straffing mission against APs escorted by PG/PCs ).

[el cid again]

What I was commenting on is that to use a B-25J with its 12 or so forward firing .50 Cals, you have to fly them at 100'. they often(always?) take a large morale hit. This will generally make them a lot less useful in the game than they were in real life. Adding a 75mm gun may or may not be useful. If they can only fly once every 14 or so days then why do it? ( I have had B-25J groups lose 40 morale on one straffing mission against APs escorted by PG/PCs ).

Flying at very low altitudes is very hard in any era - even now. It was much worse in that era because of the lack of electronic systems to help - no terrain avoidance radar - no precision radio navaids - it was ALL done in your head - and it was fast - and it was fatal if you got it wrong by more than a very short period. So the morale hit is correct.

I am not sure a 75mm gun will be used only at low altitude? I suspect it will be used at ALL altitudes. Its great advantage would be as a standoff weapon. I am not sure it is a good idea to put it in?

[m10bob]

ORIGINAL: el cid again

What I was commenting on is that to use a B-25J with its 12 or so forward firing .50 Cals, you have to fly them at 100'. they often(always?) take a large morale hit. This will generally make them a lot less useful in the game than they were in real life. Adding a 75mm gun may or may not be useful. If they can only fly once every 14 or so days then why do it? ( I have had B-25J groups lose 40 morale on one straffing mission against APs escorted by PG/PCs ).

Flying at very low altitudes is very hard in any era - even now. It was much worse in that era because of the lack of electronic systems to help - no terrain avoidance radar - no precision radio navaids - it was ALL done in your head - and it was fast - and it was fatal if you got it wrong by more than a very short period. So the morale hit is correct.

I am not sure a 75mm gun will be used only at low altitude? I suspect it will be used at ALL altitudes. Its great advantage would be as a standoff weapon. I am not sure it is a good idea to put it in?

The 75mm gun on the B25 was the same gun on the American M 24 light tank. It was low velocity and its' effectiveness was "up close and personal".
It did NOT have the range for anything except low altitude, (which is what Gen Kenney asked for).[8D]
As you will see on this USAF link, the guns were actually on the "G" and "H" models.

http://www.wpafb.af.mil/museum/arm/arm20.htm

[el cid again]

During WWII, the AAF equipped its B-25G and -H medium bombers and some Douglas A-26B light bombers with a single-shot manually loaded 75mm cannon in the nose. Though only three of four rounds could be fired during a single attack run on a target, these aircraft caused considerable damage to enemy shipping and ground targets, particularly in the Pacific. Although automatic feed mechanisms were designed to increase the rate of fire, the successful employment of aircraft rockets late in WWII halted further development of heavy aircraft cannon. But in the 1960s, the development of heavy rapid-fire cannon was resurrected for use in Southeast Asia and in other advanced ground attack applications.

I did not realize this was the same gun. It is most definitely NOT limited to strafing. In the C-130 it would operate from medium altitudes. While it is indeed not a high velocity gun, and does not have the long range we associate with 3 inch guns, it is not a short range gun either, and it has more range when fired at altitude. The real problem is targeting - and of course firing at a ground target you can spot the fall of shot just like ground artillery does - or naval artillery for that matter against ships at medium ranges. If it was replaced by rockets that tells us the range was in thousands of yards - but not in miles - in WWII applications. By Viet Nam it was in miles. This material also suggests we are missing something if we don't deal with AA rockets - which I think we can do in the form of renamed AA guns. But we need slots to do it.