Thumpalumpacus
Major
I always had an irrational love for the Meat-Chopper.
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Yes I understand the nature of SAMs, cruise missiles, Ballistic missiles etc. The heavy machine gun was however, generally effective as light AA against WW2 aircraft. Kamikaze were a special case. The M16 GMC (quad .50 on a half-track) were extremely effective against low flying aircraft in Europe. Caused some unfortunate friendly fire losses too. But they shot down quite a few Fw 190s for example. Quite effective against ground targets as well.
The heavy machine gun was however, generally effective as light AA against WW2 aircraft. Kamikaze were a special case.
The M16 GMC (quad .50 on a half-track) were extremely effective against low flying aircraft in Europe. Caused some unfortunate friendly fire losses too. But they shot down quite a few Fw 190s for example. Quite effective against ground targets as well.
I've seen .50 caliber AA described as revenge weapons. Because by the time the target was in effective range, you were already dead.Yes I understand the nature of SAMs, cruise missiles, Ballistic missiles etc. The heavy machine gun was however, generally effective as light AA against WW2 aircraft. Kamikaze were a special case. The M16 GMC (quad .50 on a half-track) were extremely effective against low flying aircraft in Europe. Caused some unfortunate friendly fire losses too. But they shot down quite a few Fw 190s for example. Quite effective against ground targets as well.
IIRC the USN didn't think so, and started replacing the 50 cals with the 20mm Oerlikons long before kamikazes came into being.
Was it "extremely effective" because the HMG caliber is in some sense the "sweet spot", or because the US produced an ungodly amount of them and sprinkled them everywhere?
In the early 1950'ies, presumably based on WWII experience as well as faster jets being introduced, Oerlikon calculated the sweet spot for a gun based AA was 35 mm, leading to the famous Oerlikon 35 mm which is still in use.
I've seen .50 caliber AA described as revenge weapons. Because by the time the target was in effective range, you were already dead.
It might have been Revenge in the sense that you are still alive to shoot the plane down, but as the aircraft would have already have dropped its bomb, or torpedo, you were about to die.That does not appear to have been the case in reality.
It might have been Revenge in the sense that you are still alive to shoot the plane down, but as the aircraft would have already have dropped its bomb, or torpedo, you were about to die.
The .50 cal and 20mm guns were pretty much for the defense of the individual ship. The bigger guns were much more often used for "fleet" defense or at least formation defense.This was also how it works with ships too, as defensive warships like cruisers and destroyers were often positioned around, and at some distance from (as in miles) the primary target - which might be an aircraft carrier, a troop transport or supply ship etc. Standard US navy formations for a carrier task force in WW2 were around 12,000 yards wide. Many WW2 aircraft that attacked ships did so with torpedo attacks, rocket attacks, or strafing, which had to be done from quite close and at low altitude.
I generally base such statements on operational histories, as in enemy units destroyed. Of which that particular vehicle did clearly produce notable results, such as during Operation Bodenplate. It seems that a couple of these things could fairly well deny a given area to low flying enemy aircraft, at that time.
I would note that the US Army did not field a 20mm ground gun.
So the choice was a multiple .30 cal (not used), the multiple .50 cal or a single 37mm or combination mount.
The one aircraft that the quad 0.5 would have had considerable difficulty with would have been a heavily armoured aircraft such as the Hs 129. Fortunately this was never a real issue
Note that I wasn't claiming they didn't work. My claim is that 12.7mm was on the small side for a really good aa weapon in WWII. Still, having something is a lot better than being without. And if you have lots of it, sure you're bound to see some results.
(The Germans considered their 20mm flak to be a somewhat marginal weapon already early in the war, due to lack of range and punch. The quad 20 mount extended the life of the 20mm as an AA weapon, although the 37mm was considered the better solution.)
You are correct however the 57mm was pretty much non-existent in WW II, They fooled around with them but very, very few were deployed.I think AA defense was typically layered. Heavy machine guns (and 20mm cannon) have the role of hitting lower and closer targets. 3", 5", 88mm, 90mm etc. are for much more distant (and usually high flying) targets. 57mm, 40mm and 37mm (etc.) are in between.
| Elevation | Distance | Striking Velocity | Angle of Fall | Time of Flight | Maximum Ordinate | ||
|---|---|---|---|---|---|---|---|
| 0.52 degrees | 1,000 yards (914 m) |
| 0.67 degrees | 1.37 seconds | 8 feet (2.4 m) | ||
| 0.90 degrees | 1,500 yards (1,372 m) |
| 1.35 degrees | 2.32 seconds | 22 feet (7 m) | ||
| 1.45 degrees | 2,000 yards (1,839 m) |
| 2.42 degrees | 3.47 seconds | 51 feet (16 m) | ||
| 5.52 degrees | 4,000 yards (3,658 m) |
| 11.37 degrees | 9.97 seconds | 442 feet (135 m) | ||
| 14.60 degrees | 6,000 yards (5,486 m) |
| 34.85 degrees | 21.10 seconds | 1,920 feet (585 m) | ||
| 40.88 degrees | 7,400 yards (6,767 m) |
| 78.45 degrees | 47.70 seconds | 8,600 feet (2,621 m) | ||
| 90.00 degrees | N/A | N/A | N/A | N/A | 19,000 feet (5,791 m) |
You are correct however the 57mm was pretty much non-existent in WW II, They fooled around with them but very, very few were deployed.
As very general rule of thumb the weight of the shell and weight of the gun (and the weight of mounting ) went up with cube of caliber. A 40mm was eight times as heavy as a 20mm.
This assumes the gun and mount allowed for and equal rate of fire
I was looking at the entry for the US 1.1in gun on Nav weapons and unfortunately the ballistics table is all screwed up.
I have moved some of the columns to where they should be. It explains a lot about actual effective range.
Just look at the figures for 2,000yds. Now figure that a 300mph plane is moving at 440fps (over a 1/4 mile) before the shell reaches it and you are using one of those cartwheel sights, from a moving deck and you have no range finder, you don't actually know how far away the plane is.
Range with HE with MV = 2,600 fps (792 mps) 1c 2c
Elevation Distance Striking Velocity Angle of Fall Time of Flight Maximum Ordinate 0.52 degrees 1,000 yards (914 m)
1,818 fps (554 mps) 0.67 degrees 1.37 seconds
8 feet (2.4 m) 0.90 degrees 1,500 yards (1,372 m)
1,470 fps (488 mps) 1.35 degrees 2.32 seconds 22 feet (7 m) 1.45 degrees 2,000 yards (1,839 m)
1,177 fps (359 mps) 2.42 degrees 3.47 seconds 51 feet (16 m) 5.52 degrees 4,000 yards (3,658 m)
775 fps (236 mps) 11.37 degrees 9.97 seconds 442 feet (135 m) 14.60 degrees 6,000 yards (5,486 m)
491 fps (150 mps) 34.85 degrees 21.10 seconds 1,920 feet (585 m) 40.88 degrees 7,400 yards (6,767 m)
434 fps (132 mps) 78.45 degrees 47.70 seconds 8,600 feet (2,621 m) 90.00 degrees N/A N/A N/A N/A 19,000 feet (5,791 m)
Nav/weps has a similar table for the 20mm Oerlikon
Just hint. time of flight to 2,000yds is 5.01 seconds.
Even a Swordfish is going to move over 900ft in that amount of time.
Well, there is leading it and there is leading it by 25 times it's own body lengthWell, if you ever went duck hunting, you know you have to lead a target.
Picket ships were supposed to be early warning. They were not the outer ring of the AA defenses.I think you are very much overstating the role of picket warships upthread a bit, but ... it's ok.