AA guns + rockets alternatives for 1935-45 (2 Viewers)

[tomo pauk]

Some countries made the greater effort, some were barely scratching the surface, while some other pretty much decided that fighters are the better use of resources. Then we have the USA, the only country that was pretty safe from the air attacks (even if their overseas territories sometimes didn't had that luxury). And thus: what plausible changes and improvements should've been introduced by the firearm-making countries in the specified era to improve their ground-based air defences? Before people say 'make VT fuses' etc, please take into account the conditions of a chosen country.

Mostly about the ground-based stuff, but if you want to add about the naval guns, go ahead.

I'll start with Italy and France: actually introduce a modern 37-40mm AA gun for the Armies, even if it is not the 40mm Bofors.

 

[Shortround6]

This covers a very large field.
The US AA guns range from the BAR mounted on a pedestal for defense of trucks (never saw active service or at least combat) to the 120mm AA gun, over 500 made but only 4 (?)went overseas.

Rockets in general turned out to be a bad deal. Rockets as in unguided. Popular for a short time with the British. Not sure if anybody else did much with them.
Guided missiles took until a number of years after the war to actually become effective.

France ran out of time, and manufacturing capability.
And here we have another split.
Defense of armies in the Field or defense of cities and factories. You actually need different guns for best results.

 

[tomo pauk]

Defense of armies in the Field or defense of cities and factories. You actually need different guns for best results.

Every gun and gunnery is a fair game here
Granted, for the field armies, we'd want something that is reasonably mobile. A number of 80-90mm pices were still good in this, but these are at a limit of what might be considered mobile. If the doctrine is to go with a hit-to-kill (Germans seem to came to that conclusion by late 1944), perhaps a high-powered 75-76mm gun might be a good idea - sorta AA siblings of the 17pdr or the Panther's gun? Trading the shell weight for the better hit probability.

France ran out of time, and manufacturing capability.

French doctrine wrt. what guns they actually want and how many, was also pretty bad. Their new 75mm AA guns were very low-powered for the as far as the AA guns of the 1930s go. The HMG was put down with it's ammo supply system, plus it was much weaker than a half-decent 20mm piece (doh).
I'd start by avoiding the HMG all together, and instead start making the Oerlikons (that the licence is already bought) for the Army needs. Don't bother with 25mm AA gun, better to make a deal with Schneider for their 37mm pieces when it was offered.

For the bigger guns - see what there is that makes about 800 m/s; if higher even better. IOW, take a look at what Navy was/is buying, and piggy-back on that, since there is a host of 75-100 mm guns that fired at reasonably high MV.
Cancel the new weak AA guns.

BTW - Japanese Navy would've been far better served with a good 37-40mm, rather than to rely on the 25mm guns. Ironically, if the French didn't had the 25mm gun in the offer, Japanese might've went with a 37-40mm gun instead...

 

[yulzari]

Rockets in general turned out to be a bad deal. Rockets as in unguided. Popular for a short time with the British. Not sure if anybody else did much with them.

Z Battery 'non rotating projectiles' did go on to form the chassis of post war AC sports cars. Just as Morrison shelters became Cooper racing car chassis with brake drums made of surplus ship engine cylinder liners. Good steel was at a premium in post war Britain. Hence Land Rovers came with aluminium bodywork not steel. But I digress from the OP.

 

[Shortround6]

A lot of times you need to develop doctrine/training practice.

The French didn't have enough of any of that.
The 13.2mm machine gun existed in the late 20s so there was time to build some, train/practice with them and establish some sort of doctrine.
Like how many per battalion/regiment?
Manned by who?
Type of transport needed? (6 men, one horse/two horses, small truck?)

French officers didn't want the heavy bullets coming back down so they waited for a gun that could use self-destructing ammo. They had the 25mm but ..........................???
The 20mm is a better deal, but it shows up late. You not only have to build them, you have to build the ammo the sort out all the rest of the "stuff".

Differences in actual ranges is less than it seems. Mostly due to crap sights.
The 13.2mm guns offered acceptable protection in the late 20s and early 30s. The planes were slow and not really strong.
Gives the AA officers and Battalion/regimental/division officers time to learn how to plan how to deploy them, where in the order of march they should go (having them at rear staying out of everybody else's way is probably not a good plan. Figuring out early warning is probably a good thing, not waiting for falling bombs?
Maybe work on belt feed or larger drum/magazine than 30 rounds?
Put the gun on a buffered mount so it doesn't move around as much when firing?

Things that can pay dividends when better guns/equipment do show up.
So the French don't do things like this.

Granted it is posed photo

Twin 25mm on a truck? Larger magazines? buffered mount/s?
Weight of twin vs single should not be that great. 4 men instead of 3?
Depends on free swinging vs hand wheels. Free swinging is faster but poor tracking.
Once you have 450rpm Oerlikon 20mms maybe switch over. Don't jump on the 300rpm version too soon.

Again what is the effective radius/height. How close do you have to put them to get coverage?

Twin 37mms may be ideal for a gun system but the cost, both in guns and in transport (trucks?)

 

[tomo pauk]

Unguided rockets must affirmatively answer to two questions:
- can it kill the aircraft?
- if so, can it do sufficiently better than the 'classic' AA stuff

In order to kill an aircraft, it needs to fly fast enough, and without the erratic movements in the flight. Even 700 m/s will not do it against the high-flying A/C (talk B-17s in the ETO); it do well might against the aircraft flying under 5-6 km, though. The Taifun rocket was supposed to do 3000 ft/s in tests (3900 ft/s was projected/calculated), while the British UP with the smaller warhead was calculated to be good for 2800 ft/s (ie. about 880 m/s).
(document)

What to do to make it better than the AA guns? Multiple launchers were a thing before Napoleon They might be able to saturate the bomber streams in the way that is not possible for the classic AA guns.

French officers didn't want the heavy bullets coming back down so they waited for a gun that could use self-destructing ammo. They had the 25mm but ..........................???
The 20mm is a better deal, but it shows up late. You not only have to build them, you have to build the ammo the sort out all the rest of the "stuff".

Even though the 25mm was a probably a better deal, apart from the ammo feed, they didn't have the 25mm in service until they basically took away other people's guns in 1938. Service-wise, the 20mm precedes it by more that a year, with 1st D.510s armed with it getting in service in the late 1936. Yes, the 20mm was also introduced too late in the AA role.
French need to decide by 1935-ish what shell-firing gun they need, and make these in good numbers.

The 13.2mm guns offered acceptable protection in the late 20s and early 30s. The planes were slow and not really strong.
Gives the AA officers and Battalion/regimental/division officers time to learn how to plan how to deploy them, where in the order of march they should go (having them at rear staying out of everybody else's way is probably not a good plan. Figuring out early warning is probably a good thing, not waiting for falling bombs?
Maybe work on belt feed or larger drum/magazine than 30 rounds?
Put the gun on a buffered mount so it doesn't move around as much when firing?

Considering that other people were making and/or buying the AA guns between 20mm and 40mm for troop protection come 1930, I'd says that French were badly behind the curve. The HMG certainly has still the problem of bullets falling down on the friendly territory, and on unlucky people it might find.

Twin 25mm on a truck? Larger magazines? buffered mount/s?
Weight of twin vs single should not be that great. 4 men instead of 3?
Depends on free swinging vs hand wheels. Free swinging is faster but poor tracking.

Problem with the 25mm was not in it's technicalities, but in that there was barely any to use. It would've certainly looked good on a truck, or on the Lorraine 37 tractor.
Compare the French with having under 500 of 20/25/37/40 mm guns total in 1940 with Germans having like 4 times the combat aircraft more, and picture is really bad.
(in June of 1940, Germans fielded 9800+ of the 20 and 37 mm AA guns, but mostly the 20mm pieces; granted, a better part of them were left in Germany)

Once you have 450rpm Oerlikon 20mms maybe switch over. Don't jump on the 300rpm version too soon.

The imperfect 300 rpm Oerlikon beats the heck out of a perfect AA gun that French don't have. It also beats their 13,2mm HMG handily, and even the 2cm Flak 30 by a small margin.

Again what is the effective radius/height. How close do you have to put them to get coverage?

Twin 37mms may be ideal for a gun system but the cost, both in guns and in transport (trucks?)

25mm will probably add another 500-700m to the effective slant range vs. a 20mm gun? Talk 2.5-3 km vs. 2+km?
Twin 37mm gun would've been perfect, at least by looking at the cartridges the the Fench were making between the wars. Again the thing of not having them in the 1st place is a kicker.

 

[Shortround6]

Unguided rockets must affirmatively answer to two questions:
- can it kill the aircraft?
- if so, can it do sufficiently better than the 'classic' AA stuff

Well, even a 50-55mm rocket has a good chance of a kill if it hits. The problem is hitting.
The rockets offered the use of cheap steel compared to gun barrels (and AA shells) but they needed a lot more propellant. Depending on the country certain propellant's are harder to come by than others.
British gave up fairly quickly on AA rockets and for an army that hung onto the Smith gun, the Northover projector and the Blacker bombard that may tell us something.
Also the Holman projector.

In both compress air and steam versions. Up to 4500 built. The British passed on a number of even stranger devices.

What to do to make it better than the AA guns? Multiple launchers were a thing before Napoleon They might be able to saturate the bomber streams in the way that is not possible for the classic AA guns.

Well, getting off hundreds of rockets in a few seconds for a very, very impressive barrage sounds good. Now how long before the attacking bombers realize that there are no follow up shots for several minutes?

Even though the 25mm was a probably a better deal, apart from the ammo feed, they didn't have the 25mm in service until they basically took away other people's guns in 1938. Service-wise, the 20mm precedes it by more that a year, with 1st D.510s armed with it getting in service in the late 1936. Yes, the 20mm was also introduced too late in the AA role.
French need to decide by 1935-ish what shell-firing gun they need, and make these in good numbers.

It may not have been a case of the 25mm not being ready, but a case of the French not ordering it. Japanese got the license in 1935 (?) and started production fairly soon after 1936?
Japanese had ordered small quantities in 1934 and 1935.

Considering that other people were making and/or buying the AA guns between 20mm and 40mm for troop protection come 1930, I'd says that French were badly behind the curve. The HMG certainly has still the problem of bullets falling down on the friendly territory, and on unlucky people it might find.

The French were certainly behind the curve. The Swedes had a 25mm Bofors gun in 1932.

also available as a twin.
Soviets were also working on a 25mm AA gun during most of the 1930s and just got it into production in 1940-41 although production didn't large numbers (4 digits) until 1943.

Problem with both of these it that they didn't fire that much faster than the 37-40 mm guns and required similar crews.
But in the 1930s, against mid/late 1930s aircraft the 25mm guns may not have been seen as deficient as they appear to eyes used to 37-40mm guns of a few years later.
The French were fooling around with semi-automatic 37mm AA guns, same breech mechanisms as AT guns, Human loader has to toss the round into the open breech. Makes the 25mm Hotchkiss look like a wonder weapon. The French 37 automatics appear way too late.

25mm will probably add another 500-700m to the effective slant range vs. a 20mm gun? Talk 2.5-3 km vs. 2+km?

effective range of a lot of these guns needs to be take with a large dose of salt (block for livestock?). Granted a trained crew with a good sight and good conditions might reach the published figures. US Navy and Royal Navy figured 20mm effective range was closer to 1km than 2km but that was with the cartwheel sight/s. They also had a number of years trying to train large numbers of recruits to use these guns. What was the results of the average gunner, not the best 2-3 out of a class of 100

With the guns firing under local control with estimates on speed and course coming from the gun captain (or gunner himself) and not having a range taker over their shoulder effective range often had little in common with the book numbers.

 

[wuzak]

Well, getting off hundreds of rockets in a few seconds for a very, very impressive barrage sounds good. Now how long before the attacking bombers realize that there are no follow up shots for several minutes?

The question is whether the barrage is successful in breaking up the formation.

If the barrage can kill a few aircraft, and scatter the formation, it may help Luftwaffe fighters pick off the bombers.

That's how the Werfer-Granate 21 air-launched rockets were used.

They had about 10kg of explosive filling, around the same weight as the shells used by 88mm Flak guns.

 

[wuzak]

The Germans did develop some radio guided rockets, but these were big and probably very expensive to use.

The Rheintochter weighed just over 1.7t at launch and carried a 136kg warhead. It was also limited to ~8km (26,000ft) altitude
The Wasserfall weighed 3.7t at launch and carried a 235kg warhead.

The Taifun was cheaper, had a higher speed (3,300km/h according to Wiki), but only a 500g explosive charge. And it could get up to 50,000ft.

How much explosive filling in a typical 88mm Flak shell?