AA artillery

[Borys]

The thread on the Chinese Republic "Atlantas" made me wonder ...

http://www.navalism.org/index.php?topic=3146.msg34808#new


I don't really understand it the AA tech - but I admit I never gave it a thought until now.

In 1900 we have:
- high angle anti ballon guns means something of 2,5"-3,5" calibre. Slow firing. And 1 pounder machine guns, something between 1" and 1,5" calibre.

Then, in 1908 we get 2 pounders (pom-poms), with the slow firing larger calibres disapearing?

IIRC, it was P3D (or was it Maddox?) who wrote this rule. What was the intended meaning?

Borys

[maddox]

Hi angled anti balloon guns, you could see those as normal artillery pieces mounted on pedestals, or set up on hillsides to get a higher elevation. The problem with this solution was the slow or non traversing , and the low power the pieces could be fired when mounted on a pedestal.

Later on these akward, cumbersome solutions were abandoned and faster firing and moving guns of smaller caliber were used, especialy when aircraft became faster and more manoevrable.

[Korpen]

My thoughts on the issue:
Ignore the part about the size of the guns, it is irrelevant. Converting a suitable gun for high angle fire was easy, and often done in day by men in a workshop. This is especially true for naval and fortresses applications were weight was not a major concern.
The AA tech should have almost nothing to do with the guns themselves, but with all the associated methods to actually hit something. So the tech would represent things such as accurate gun tables for engaging targets in three dimensions, having ammunition that is suited to the task (tracers, or time-fused HE, or at least shrapnel that one can time for the purpose), and firecontrol that can cope with engaging a moving target high in the air. 

[The Rock Doctor]

If somebody wants to propose an AA Tech tree based on science, rather than gun size/max height, I'm all ears.

[Korpen]

If somebody wants to propose an AA Tech tree based on science, rather than gun size/max height, I'm all ears.

A first shot in the air then:
1900: Baseline: Guns capable of firing at high elevation, normal field gun ammunition (time fused shrapnel & impact HE). Hand trained machineguns and Pop-Poms. Small rangefinders. Listing horn early warning. Searchlights
1908: Adv: Purpose designed ammunition: reliably fused HE shells and tracers for single shot guns. Tracers for MGs and Pom-Poms. Fire control boards.
1914: Incendiary tracers for MGs and Pom-Poms, central post battery control and electro-mechanical sight and fuse setting machines.
1924: Futuristic: automised fuse setting machines, multiple barrelled centrally controlled pom-poms. Integrated searchlights. Integration of external sensors.

How does that look?

[The Rock Doctor]

Interesting.  I think I'll have to compare with the FC tech.

[Carthaginian]

Korpen's tree looks good... I like it's general layout.

A caliber limit should be in place as well, if for no other reason than to ensure that we don't wind up with a fused 40mm autocannon that could shred a WWI era aircraft. I propose the following amendment:

1900: NONE - no aircraft to shoot at.
1914: Machine guns pointed at the airplane, field artillery pieces (76mm and below) on HA mounts.
1918: Dedicated AA machine guns (up to .50"/13mm), purpose-built HA artillery (76mm and below), early timed fuses; early search lights, early acoustic warning devices
1922: AA autocannons up to 25mm, twin AA machine guns (up to .50"/13mm), improved timed fuses, purpose-built HA artillery (105mm and below); improved search lights, improved acoustic warning devices
1930: twin mount AA autocannon (up to 1.5"/40mm), triple/quad AA machine guns (up to .50"/13mm), perfected timed fuses; perfected search lights, perfected acoustic warning devices.
1935:  triple/quad autocannon (up to 1.5"/40mm), purpose-built HA artillery (5"/125mm and below), AA machine guns (up to .50"/13mm) up to 8 per mount; early air-search radar.
1935:  central directors, twin mount purpose-built HA artillery (125mm and below); improved air-search radar.
1945: Rapid-fire HA artillery (76mm and below); perfected air-search radar.

[Borys]

"early timed fuses"

Already included in contemporary shrapnel rounds.

Rest looks OK - although pom-poms predated planes by almost decade :)

The various weapons in 0,5"-2 pounds range will simply be grandfathered, I hope.
Like my 1,25" 1 pounders.

Borys

[Korpen]

Korpen's tree looks good... I like it's general layout.

A caliber limit should be in place as well, if for no other reason than to ensure that we don't wind up with a fused 40mm autocannon that could shred a WWI era aircraft. I propose the following amendment:

Do not think it should be any calibre limit as such. You had quite a few early auto cannons with calibres of around 40mm even before 1914. Those guns were basically scaled up MGs, but were dedicated as AA guns from the beginning. If any limit is going to be put in is would be about multi gun mounts for automatic guns and/or clip feed. Considering how fragile aircrafts were until the 20s at the earliest pretty much a hit from anything from a 12,7mm HMG and up would be likely to disintegrate the aircraft.

Do not feel any need to put size limits on the single shot guns, as the difference in efficiency is marginal, and that designing and pointing a gun towards the sky is very easy.
Timed fuses should exist from the beginning as it is standard on field artillery shrapnel shells. The problem was just that for HA fire, or against balloons and zeppelins you wanted HE shells. And shrapnel fuses did not fit into the smaller fuse socket on HE shells.

So it was often mostly a case of assembling existing components in a new way so that is could be utilised in air defence.
The "baseline" as I wrote it is basically what you get by taking what you have and telling skilled workers (either in a dockyard or a gun factory, or perhaps a rail yard) to mount is can fire at up to 70 degrees elevation.

[Carthaginian]

The problem is, you go directly to the second stage as soon as powered flight comes in, Korpen. You don't allow for any lead time, or combat experience, to dictate the need for development of such tech.

There must be some delay between the appearance of aircraft and the appearance of weapons effective against them; your tech scale effectively negates the 'action, reaction' nature of military technology by putting AA technology a generation or more ahead of the aircraft being built!

[Guinness]

The RN introduced the 2-pdr (1.575") AA in 1915. Even if we grant that it would have come later except for the war, I think anything later than 1920 is probably too late.

In the period's AA, there were two concepts:

1. Smaller, faster firing guns, for use against lower altitude targets with faster changes in elevation and training angles (ie strafers and dive bombers)

2. Larger, slower firing guns for use against higher altitude targets with slower changes in elevation and training angles (ie high altitude bombers and torpedo bombers who could be expected to fly on a predictable heading at a steady altitude)

The fire control problems for the two were markedly different. The second class were largely "aimed" in barrage fire well up until WW2. Fire control for them didn't become effective until automated fuse setters, and ultimately proximity fusing. The first were largely aimed by eye well into WW2.

These still have (somewhat generous) effective altitudes in them, but just to illustrate capability.. So with that preamble, my humble suggestion:

1914: Machine guns up to 1" (25mm) caliber, aimed by eye.
1919: Autocannon up to 1.575" (40mm) caliber, aimed by eye. Improvised barrage anti-aircraft weapons up to 3" (76mm) firing timed exploding munitions, effective to altitudes of 10,000 (4700m) feet.
1924: Purpose built barrage AA guns up to 5" (127mm) with elevations up to 45 degrees. Effective to Altitudes of 20,000 feet (9400m).
1929: Dual purpose guns up to 5" (127mm). Dedicated barrage AA weapons with elevations up to 85 degrees. AA plotting tables.
1934: Dedicated and Dual purpose elevations up to 90 degrees for barrage AA weapons. Early lead computing gunsights for automatic AA fire. Early radar guidance for barrage AA weapons. Automated fuse setters and barrage AA director fire.
1939: Mature lead computing gunsights. Improved radar guidance for both automatic AA weapons and barrage AA weapons. Proximity fuses for guns larger than 3" (76mm).

Or something to that effect. The years can slide here or there a bit, but I think the progression is good, and captures the technical challenges that defined AA effectiveness. A theoretical 1944 tech would include automated AA guns up to 6" (ie US Worcesters, etc.), and maybe a few more goodies after some research. Of course, once you have radar guidance and directors, this tech starts to commingle with fire control and radar tech too.

[Carthaginian]

I like Guinness's proposal the best... better than my own.
Less limitations, but solves the same problems.
Good work!

[Guinness]

Thanks! I made a little edit to clarify elevations for barrage AA just now. Don't think it makes much of a difference for this conversation though.

[Korpen]

Thanks! I made a little edit to clarify elevations for barrage AA just now. Don't think it makes much of a difference for this conversation though.

I do not think there is any reason to have limitations on the calibre of the guns. For the light ones it is IMO better to restrict it to belt or hopper fed (no clips) single barrel, single mounts.
As for the single shot ones I really see no point in size restrictions as AA guns were usually developed from what countries already had, and naval guns often became excellent AA guns with no modification except elevation.

But want I wanted to put forward was the fact that the guns themselves are the least important thing in the evolution of AAA, and that we have different tech (gun tech) covering the development of that hardwere (granted that the dates should be changed allot).

[Carthaginian]

Korpen,

We have no real differentiations in 'effects of ammunition feed' in our abstract system.
Also, caliber limitations are somewhat realistic, in that if you look most nations did not exceed 25mm for AA weapons for some time... generally near WWII! Also, 3" AA artillery was generally viewed as sufficient until somewhere in the late 20's or mid 30's- depending on the Navy in quest1ion.

Limiting the calibers was, again, a method to prevent our hindsight form kicking in and ensuring that aircraft never make an impact in naval warfare. I mean, if you have timed-fuse 5" guns firing against 1908 aircraft (as you have your tech set up) then NO ONE would even attempt using aircraft as a weapon- the defenses available would make them pointless!