Auxiliary interceptors

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About 20 years ago people thought giving semi-active laser guidance to a 70 mm hydra missile would cut costs, for Hellfire misiles were expended on Afghna  and Iraqi cars. It took a while, but APKWS II has been in service both for helicopters and aircraft, with occasional experiments to use it as a surface-to-air missile. These missiles turned out to be the best cost:performance munitions in Western arsenals and even the EXTREMELY wasteful CENTCOM has adopted their use to down Houthi Shaheeds.

 

https://www.twz.com/air/f-16s-with-larger-laser-guided-rocket-loads-drone-kill-marking-emerge-over-middle-east

Their advantage isn't just the low costs (though using 1980's and 1990's era infrared guided missiles is kinda free, for they are already in inventory). You can carry 14 (2x7) or 19 such small missiles instead of two normal infrared guided missile or five LMMs under one pylon. I know of no LMM-certified fighter, but most Western fighters can carry a Hydra pod or NATO-origin equivalents. 

 

They have also been used over Ukriane to down Russian cruise missiles of sorts. 

 

 

Europe has smartened-up Hydra equivalents to APKWS II equivalents: 

https://en.wikipedia.org/wiki/FZ275_LGR

https://en.wikipedia.org/wiki/SNEB#Laser_guidance_development

(more details on German wikipedia)

I'm not sure whether FZ71 features proximity fusing, but ACULEUS 68 LG does.

 

So these are the European APKWS II alternatives that can serve as cheap air-to-air missiles against munitions. They require laser target designation.

 

Semi-active laser guidance basically uses a laser to illuminate the target at a specific wavelength typical of the kind of laser and a seeker that just pays attention to this wavelength (with a little tolerance to account for doppler shift). This means the starget could be stealthy to it by either scattering the light (avoid returning it 180° back) or absorbing it extremely well (most likely a combination of it). 

 

An imaging infrared seeker is under development for such rockets, but it might cost a lot more. There's the open question whether semi-active laser works against terrain following missiles. I don't know. Maybe the missile would chase the reflections on the (back)ground instead.

 

 

Such cheap A2A missiles might be the munition of choice for intercepting cruise missiles over land, both cheap and expensive ones. Fighters with built-in 30 mm gun might use a 30 mm proximity-fused HE cartridge instead, but these guns are AFAIK not prepared for single shots and AFAIK only Americans produce such fuses. 

 

The platform needs to match and at least briefly exceed their cruise speed, which rules turboprop aircraft out. 

The establishment may be able to assign jet trainer aircraft this mission, equip them with a FLIR with laser target designator plus whatever avionics it takes to coordinate a search line or hunt a particular missile. The problem here is that jet trainers fell a bit out of fashion (exception being the new high performance M-346) because of modern high end turboprop trainers and having jet trainers in the own air force somewhat fell out of fashion a swell because training in a joint establishment was more cost-efficient. 

 

Another aircraft category that might come to the resuce are the business jets. Some of them have the size and flight performance to catch up even with turbojet-powered normal (not Shaheed-style) cruise missiles such as Kalibr (Mach 0.8 at very low altitude). They could fly at medium altitude for superior speed and dive close to their never exceed speed, then maintain M 0.8 long enough for the kill. It's mostly the big and long-range business jets that are this fast, though. There are about 700 business aicraft registered in Germany, but the vast majority will be unsuitable to more than interception of jet Shaheeds.

 

Fun fact; there was a project for using a business jet airframe as interceptor before, and it featured afterburners to catch up with business jet smuggler aircraft.

 

 

 

We should prepare: Choose business aircraft (and jet trainers) that are available (could be commandeered), test and certify them with equipment for the auxiliary interceptor role (including IFF), develop their integration into the air defence scheme, prepare the conscription of ground crews and pilots. We could greatly complement the normal fighter fleet in face of saturation attack waves.

S O

defence_and_freedom@gmx.de

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New frigates for the German navy

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I did recently write about an optimal escort (GP frigate) and a minimum escort (GP frigate or corvette). I also wrote about modern (naval) escorts in general in 2018. Now I'll write about a realistic sensible option for a new German frigate. I refuse to be bothered by the overpriced official designs and that offer from a frigate-inexperienced arms supplier.

 

First thing first; FUCK BMD (ballistic missile defence) of the American way (hard kill). It's too expensive to build a ship for hard kill defence against quasiballistic/aeroballistic medium range missiles or hypersonic missiles. Those missiles likely have difficulty hitting ship targets (particularly the correct ones) without any defences in place anyway and the recent ballistic missile wars of attrition around Ukraine and Iran should have brought home the point that you can be forced to run out of hard kill munitions (two expensive interceptor missiles per incoming missile or warhead), so I stick to my opinion that we should exercise self-discipline and modesty and accept that in war you take some blows. This means we need early warning (mostly by satellites and offboard radars) and A LOT of soft kill countermeasures. Basically, the incoming missile should not "see" its correct target in any spectrum and it should see lots of obscurant also in a safe distance to the real target.

This kills the entire BMD-heavy approach. A two-ship convoy escort shouldn't aim for having any super AAW destroyer, either. The escorting would happen far away from Russian (or Chinese) air bases and a few AAW destroyers wouldn't help much if the Americans or Chinese attack Europe.

The threat scenarios remain the same as in the minimum frigate blog post: Multiple boats, one auxiliary cruiser, divers, explosive boats/semi-submersibles in port, submarine trying torpedo attack (incl. from ambush position resting on seabed and having anti-helicopter air defences), salvo of up to 32 stealthy or supersonic anti-ship missiles incoming, strike fighter trying to drop guided bombs from very high altitude.

Keep in mind spending domestic means about 40...60% of the spending returns to your own country's public finances as taxes, saved unemployment pay and so on. That's a rule of thumb, but in today's Germany we should relax about it because we have a skilled labour shortage - the additional spending doesn't lead to additional government revenues if it fully crowds out other spending.

Moreover, all equipment that's dependent on American, Chinese, Russian, Indian political goodwill is untrustworthy. All equipment from these countries that can receive and process radio signals is untrustworthy. The Englishmen are confused about whether they're Europeans  or Americans, have proven to almost exclusively elect terrible politicians (even a lying clown) and are a five eyes member, so they are a bit suspect as supplier as well.

As a base, I take the FDI, which by today would probably cost 600...750 million € apiece if ordered from French shipyards if they had the capacity left. Plus development expenses for modifications.

Such FDI frigates would not be battleships, they would be escorts. Look at the dedicated convoy escorts of WW2 (example). They weren't high end - they were the low end component (and mostly built in wartime or repurposed old ships). A clearly-defined mission set allows for an affordable design that's of some use outside the core mission set as well (see destroyer-escort action at Leyte Gulf '44). 

• CAPTAS -4 towed sonar: great
• bow sonar: good enough for the French = good enough for us, I guess 
• antenna mast including four AESA radars: not my preference, but changing this would incur delays and extra development costs. Add the (cheap) Sea Giraffe 1X as expected for the Swedish FDIs, the Swedes likely pay for integration.
• optronics: check whether replacement with Hensoldt equipment (Mirador with German optronics as on K130) makes sense

• 24 VLS for Aster 30: The newer Aster 30 NG is meant to be a capable hard kill defence against short range aeroballistic missiles. It should suffice against Oniks and possibly Zircon missiles.
• 24 VLS for CAMM-ER missiles (as likely to be integrated for the Swedish FDI order) or with additional systems integration costs the more trustworthy (at least to Germany) 24 IRIS-T SLM.
• 76 mm gun: It's acceptable for a ship this size, though you'd need a very close convoy formation to protect a convoy with two frigates against cheap drones. Luckily, masses of cheap drones and torpedoes are rarely a threat at the same time, so the detrimental effect of a close formation on sonar operation is not too bad.
• Exocet 3C: Replace these with 2x4 refurbished RBS 15 taken from K130 class, for the French likely integrate these for the Swedish FDI order anyway, at Swedish expense.
• Torpedo tubes: These lightweight torpedo tubes are marginal weapons, but they may double as storage containers for ASW torpedoes and might be useful for hard kill anti-torpedo defence sometime.
• 20 mm Narwhal: We should be able to refurbish, update and re-use 27 mm MLG27 from decommissioned F123s instead. 20 mm Narwhal would be acceptable if systems integrations of MLG 27 costs much or if MLG 27 is too big.
• Mistral: I have very low expectations for the effectiveness of Mistral, so I would use its positions (and others) for soft kill launchers. This would include RF fog (Pandarra fog/chaff), MASS and 3DDS. 

• Hangar, helipad, MH-90 helo: Regrettably, we already purchased these gold-plated and troubled helos, so we should not procure any other medium ASW helo for this.
• Flying drones: I strongly suggest using the Malloy T-650 for torpedo and sonoflash active+passive sonobuoy delivery. Its range should be improved by getting better batteries in the next years and by using the Italian A244S/Mod 4 torpedoes for their lower weight. I trust six such drones much more than a single medium helo.

• Stick with the Thales SETIS 3.0 combat management system! To replace the CMS would require much more systems integration budget than switching Narwhal to MLG27, adding soft kill systems and adding the T-650.

• The public knows little about soft kill defence against torpedoes. FDI has a acoustic decoy/jammer, but I have yet to see a published answer to wake-homing torpedoes. Maybe a hull vane, a towed counter-torpedo mine or just go slow?

Why no RIM-116 RAM? Because the ones in inventory are getting old, new ones are ridiculously expensive and they might receive a kill switch code signal from an American anti-ship missile via their RF receiver. Moreover, surplus RAM from decommissioning F123s would boost munition stocks for F125s that use RAM.

Have a honest tender for building these ships in Europe. Domestic offers get a 25% discount on domestic value added in the tender, but the domestic shipyards absolutely should lose the bids if they are much more expensive than foreign bids. The license fees would have to be paid by the shipyard.

Most of all; change the personnel system, so we can cut down operating expenses and make do with ONE crew.

- - - - - 

The F123 and F124 frigates should and hopefully will be decommissioned before the late 2030's. The K130s are very weak, but they could bolster a two-frigate convoy defence with a bit more firepower against sea skimmer missiles up close, drones, ships, add some UAVs and help with SAR. The new frigate order would create the German surface navy mainstay by the late 2030's.

 

In the meantime we should focus on the readiness of the only really capable (though Americans missiles-compromised) F124 frigates, sell off the K130 (including the new ones, which aren't worth the operating expenses to us) to allies. The F125 frigates should receive the planned upgrade with IRIS-T SLM and should also be upgraded with CAPTAS-4 Compact. Both needs proper CIC/CMS.

 

All of this only if one thinks that having a German frigate fleet makes sense, which is very debatable IMO.

 

 

There's no one size fits all. Different navies and different times lead to different appropriate solutions - and nobody is obliged to agree with me on which solution is appropriate. We know for sure that the German naval procurement has been total crap for a long time, though. K130 and F125 are underarmed subsidy programns for shipyards. The 3rd EGV was a brazen shipyard subsidy as well. F124 is now Americans-dependent and was IMO underwhelming until ESSM Blk II. The F123 ASW frigates are helicopter-dependent and their sonar equipment remained underwhelming despite upgrade opportunities. Meanwhile, we neglected readiness, spare parts stocks and munition stocks. So what are the odds that the German navy is getting it right now?

 

S O

defence_and_freedom@gmx.de

update: Add a trainable ASW rocket launcher.

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Minimum GP corvette or frigate

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Suppose a navy would want the cheapest viable general purpose warship design rather than an optimal one. Compromises have to be made, especially skipping on the capabilities that drive costs the most.

The warship would be a corvette (less than 2,000 tons) for use in coastal waters such as the Mediterranean or North Sea and a frigate (about 4,000 tons) with exact same military capabilities except for better seakeeping and more endurance (fuel, crew food and accommodations) for a longer cruise (examples Portugal-Azores-Canada, Portugal-Azores-Brazil, Japan-Philippines-Australia) with deployed towed sonar (extra drag) at 15 kts (not on straight course, for all-round detection performance).

 

French FDI frigate (a relatively small FFG) from its most flattering angle
symbol photo / photo: Naval Group

Here's my concept for this:

Sensors:

• multi-purpose 3D radar for detection of flying objects at weapon range + margin that allows the crew to make full use of that range (Sea Giraffe AMB with relatively very cheap Sea Giraffe 1X for support and as backup on a different mast). IFF interrogation.
• additional multispectral sensors for air & sea search, tracking, identification and ranging (two gimballed optronics heads including visual, UV, thermal, laser rangefinder)
• Towed sonar for sensing, direction-finding and identifying submarine noises, ship noises well beyond horizon, torpedoes. Much better capability against deep submarines than bow sonar.
• Bow sonar direction-finding and ranging submarines and torpedoes especially in shallow waters, mine avoidance. Secondary diver detection & repelling and ship detection & direction finding beyond the horizon capabilities. This is indispensable for shallow waters where the towed sonar doesn't work.
• Naval mine-confirming capability (the cheapest option would be a diver, but it's slow and depth-limited - the latter matters against rising mines)
• VTOL UAV with zoomable visual spectrum and thermal cameras, secure datalink for remote identification of ships and boats as well as SAR support. It might have some use for early warning against sea skimmer missiles.

If this sounds a bit much for a minimum GP warship, keep in mind I omitted a long-range air search radar and BMD radar capability.

Effectors/weapons:

• Very much chaff, multispectral smoke, pandarra fog and DRFM quadcopter decoy rapid launch capacity 
• Ability to deploy a towed and sometimes free-moving boat with active radar jammer to act as semispherical home-on-jam decoy
• Plenty capability to deploy anti-torpedo decoys, possibly including mine-decoys that damage the torpedo if it comes too close.
• A few (4 ~Aster 30/IRIS-T SLM minimum) medium range air defence missiles capable of minimum 15 km effective ceiling at distances that deter laser-guided bomb attacks, also capable of taking on subsonic and supersonic sea skimmers. This is more about repelling effect and reduction of enemy freedom of action rather than about actual destruction.
• Much more (28 ~ IRIS-T SL/Sea Ceptor minimum*) short range air defence missiles capable of taking on sea skimmers of subsonic and supersonic speed out to horizon distance. A Russian SSGN may launch 32 submarine-to-ship missiles. This requires a total 32 air defence missiles per frigate as outer defence layer assuming all RUS AShMs function properly, two escorts for a convoy and two interceptor missiles per incoming missile. Secondary capability against speedboats.
• A main gun capable of damaging ships, destroying boats and flying objects (minimum 76 mm)
• One or two secondary autocannon(s) with good depression and very wide arc of fire, mostly for defence against explosive boats in port, but also to be used to support the main gun (20...30 mm)
• Light anti-ship missiles (16 Sea Venom, for example**). Basically, the frigate should not be powerless even against an armed merchantman from WWI and it would be very weak against it if limited to a 76 mm gun and SAMs. Frigates are no major ASuW assets in naval warfare, but a GP frigate should have a modicum of ASuW capability as a hedge.
• Multicopter-delivered lightweight torpedoes, possibly also to be recovered by (another) multicopter). I don't fully trust this, but I chose this with the "minimum" mindset in mind. The quantity of lightweight torpedoes carried onboard depends on whether they are reusable (ideally rechargeable battery, this also helps a lot with affordable training). Call for reinforcement or support firepower in case of defeat of the multicopters by a hostile submarine
• Naval mine-removal capability (the cheapest option would be a diver, but it's again slow and depth-limited) 

I did not bring up kamikaze drones for defence against boats because that approach may be relatively slow (less than 50 m/s) and more importantly, boats could more easily shoot down propeller-driven drones with a typical 30...76 mm gun FAC gun than actual rocket-propelled missiles such as Sea Venom (about 290 m/s in a dive). Hypersonic missiles have advantages and disadvantages - I limit the defence aginst them to generous application of decoys and concealment (RF, visual and IR) and timely warning by sensors because hard kill defence is too improbable and expensive.

Other

• Prepared for getting replenished (fuel and food) at sea
• Helipad with beartrap, hangar for drones & one light SAR&liaison helicopter (H135***) with twin engines (FLIR, EFS inflatable winch, rappelling ropes and removable exterior benches in MH-6 style, possibly towed MAD, possibly two Sea Venom missiles or low frequency passive sonobuoys)
• One 7 meter RHIB
• SatCom and secure datalinks
• An ops room with hardware and software for ASuW/AAW/ASW, the peak performance requirement is the coordinated defence of a small convoy against 32 supersonic anti-ship missiles by two frigates including remote activation of chaff dispensers on the escorted ships. It also needs to be capable of initiating timely soft kill countermeasures when a BMD or hypersonic missile warning pops up.

This is different from my rather optimum-minded concept for a frigate in some ways, notably

• no long-range SAM (SM-6) to be used in cooperative engagement based on external sensors only
• much-reduced area air defence ambition in general
• much-weaker gun armament
• much less capable anti-ship missile armament against warships
• minimum size viable low frequency active (towed) sonar capability
• could possibly fit into a corvette-sized ship
• LWT**** to be deployed exclusively by cheap multicopters, no priority for the more expensive ASW missile approach.

Similarities that are different from mainstream:

• Not opting for expensive medium ASW helicopter that's not going to fly for more than 4-6 hrs/day (=not helping much with submarine detection 24/7 unless you have 4-6 helos in the convoy) and have questionable survivability in case the submarine deploys some air defences.
• Choosing early warning + soft kill as the only countermeasure to hypersonic missiles.
• two-tiered air defence missile layout for cost reasons (Aster 15/30 is at times two-tiered because Aster 15 has a shorter minimum interception distance than Aster 30, not for cost reasons)
• total rejection of a main gun calibre smaller than 76 mm

 

I am no proponent of European countries buying frigates, but I do see potential for well-rounded and viable frigates that might end up costing well less than 750M € including munitions, aviation component and other peripheral costs. 

S O

defence_and_freedom@gmx.de

 

*: RIM-116 RAM is ridiculously expensive and has inferior range. VL MICA is too expensive as well. Sea Ceptor still appears to cost more than IRIS-T SL and the latter proved itself against Kalibr missiles over Ukraine, so it's my first choice. Maybe the Korean K-SAAM is fine, but I don't know much about it.

**: Sea Venom has such a small warhead that it's rather a subsystem-damaging missile than a ship killer, but NSM is on the light end compared to most AShMs and a ship killer at most against corvette-sized targets itself. I'd prefer 16 Sea Venom over 4 NSM due to much lower total cost and much greater capability against a large quantity of small boats. As a downside, the Sea Venoms would merely target main gun, 3D radars, helicopter hangar (or helicopter on helipad), VLS and other missile launchers on a frigate or destroyer target rather than trying a bigger killing blow to ops centre, engine rooms or a horizontal impact towards VLS.

***: Regrettably, the H-6 family (8.03 m main rotor diameter) has only one engine, which is a bit risky over sea. The 10.2 m main rotor diameter of a H135 is small enough to store the single helicopter in a corvette's (typical corvette beam = 10...13 m) hangar without folding. The UAVs would be stored around the helicopter under its main rotor circle (helicopter fuselage width 2 m, Malloy T-600 LWT-carrying multicopter width 3.72 m, sensor UAV helicopter width less than 1.5 m). 

****: This may require the use of one of the lowest weight lightweight torpedoes. This would be for the normal 324 mm LWT diameter the Italian A244S Mod 4 (~254 kg) or the seemingly superior Indian TAL Shyena (220 kg). Most LWTs weigh more than 300 kg.

update: Add a trainable ASW rocket launcher.

update 2: I forgot to mention that a helo (or multicopter) may serve as a radio repeater so the Sea Venom can be used beyond with man-in-the-loop mode at distances greater than the radio horizon. They would also serve as repeaters for the radio signals of the sonobuoys (and even a light  helo has much better endurance for this than a multicopter).

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Optimal AAA calibres in WW2 and today

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Here's a shipload of hindsight: The optimal anti-air artillery calibres of World War Two.

7.62...7.92 mm machineguns were rather ineffective. There were some aircraft with thin armour plating during WW1 already. Such armour plating provided good protection at as little as 300 m altitude, for the bullets quickly lost energy by climbing against gravity and drag. The use of twin or quad mountings didn't help much. 

12.7...13.2 mm machineguns were little better. Their effective range was around 500 m, but they had the target in range for so little time that they depended rather on lucky hits to achieve much. The use of quad mountings didn't help much. It's irritating that the Soviets nevertheless introduced 14.5 mm anti-air machineguns based on their anti-tank rifle calibre after WW2, including multiple barrel mounts. Their usefulness was mostly limited to anti-helicopter work and the slightly bigger 23 mm twin gun (a Cold War design) was vastly better.

A single Czechoslovakian 15 mm gun design was of marginal relevance. It was too much gun and mounting for the modest effectiveness of the calibre.

The first really effective AAA calibre was 20 mm. It's widely recognised as the smallest calibre for a useful high explosive round with a proper fuse. 20 mm weapons weighed about double what 12.7 mm weapons weighed during WW2, but their weight was still bearable. 20 mm quad mounts were very heavy, but it was possible to devise a 20 mm light AAA pack gun. The calibre was also very effective in ground support and against merely bulletproofed AFVs (most early WW2 tanks and late in WW2 still the scout vehicles and halftracks). This was the best calibre to equip infantry regiments or even infantry battalions, but this was hardly ever done. The result was that the infantry was largely without proper air defences, but at least the infantry was fairly good at using camouflage, concealment and cover. This happens to have been the reason why 20 mm would have been sufficient for an infantry AAA capability: Its up to 2 km effective range covered approx. the distance at which aviators could still spot infantry targets save for road marches and field fortifications on open fields.

There were some 25 and 28 mm AA guns in France, Japan, Soviet Union and the U.S., but they did not earn good reputations. Japanese 25 mm suffered from sluggish mountings and a ceiling that permitted very accurate level bombing against anchored or moored ships from a mere 7,000 ft altitude.

The next really convincing calibre was 30 mm. The German 30 mm HEIT (high explosive incendiary tracer) Minengeschosse were designed for a giant explosive charge with added incendiary side effect. One hit usually sufficed to shoot down a single engine aircraft. Even the rugged 4-engine B-17 was said to usually be doomed after four 30 mm HEIT hits. This was in part because of the huge blast effect an in part because the fuse was designed to explode just after penetrating the skin, so it would explode inside a wing or stabiliser. 30 mm wasn't only a sweet spot for its destructive power leap over 20 mm. It was also a sweet spot because the late WW2 Mk 103 showed that a huge rate of fire (for a light AAA at the time) and a high muzzle velocity was doable with this calibre without excessive weight of the whole system. The effective range was greater than 2 km in the AAA role with its muzzle velocity without needing a muzzle velocity at 900+ m/s, which would have worn out the barrel too quickly. So IMO a 3 cm AAA of about the Mk 103's weapon design (with a suitable mount) would have been the perfect light AAA for divisional air defence and SPAAGs. It would have reached higher than 2 cm guns, pushing the threats farther up to altitudes (8,000 ft and more) from where the rear elements of a division (esp. artillery positions) would be much less recognisable. Hardly any 3 cm AAA was used during WW2.

Next, there's the 37...40 mm group. These guns had vastly inferior rate of fire to 3 cm Mk 103, but the destructive power of late war HE-rich grenades left almost no chance to single engine aircraft with even only one hit and approached one-shot kill power against medium bombers. Moreover, they had increased reach than smaller calibres. The altitude of 10,000 ft was considered to be safe from them during WW2. Some of their fuse designs self-destructing at about that distance anyway, so greater theoretical ballistic ceilings didn't matter. This calibre was the best fit for naval guns. It pushed level bombers so high that they became too inaccurate even against anchored or moored individual ships. They made twin-engine skip and torpedo bombing inefficient or (if they got close) suicidal. It was a powerful-enough calibre for motor torpedo boats to fend off motor gun boats. The effective firepower against ground attack aircraft at short distances was certainly vastly inferior to the much higher practical rate of fire of 3 cm Mk 103, though. I'd like to add that the British 2 pounder went back to WW1 and this explains its poor muzzle velocity, which rendered it rather unimpressive against aircraft passing by. The 4 cm Bofors of the late 1920's was the best and earliest really good gun in this calibre and would still (even with 1980's munitions) be a very good AAA in face of the cheap cruise missiles used in the Russo-Ukrainian War.*

The 45...47 mm calibre group was a bust. The Soviets used it on ships, the Czechs had some developed, but these guns had a terrible rate of fire and marginal advantages over 4 cm.

The 50...57 mm group began with a German 50 mm gun meant to close a gap between 10,000 and 15,000 ft altitude at which 37 mm was ineffective and heavy AAA (88 mm) not yet effective-enough because of high angular speeds and rapid change of necessary time fuse settings. This was a sweet spot for level bombing during WW2 and also relevant over the Reich because of the poor service ceiling of the Short Stirling night bomber. Eventually, the 50 mm calibre proved to be too weak and Germany advanced to develop a 55 mm gun, but only completed prototypes. Its combination of calibre and muzzle velocity indicates that it would likely not have covered the 10,000 to 15,000 ft gap. 55 mm was considered to be capable of reliably one-hit kill even a 4engined bomber such as a B-17 or Lancaster.** A properly-developed 55 to 57 mm gun would have proved very useful for protecting railheads, railway stations, bridges and (against night bombers) cities during WW2. Basically, it would have been the perfect defence against light and medium bombers and heavy bombers used in typical medium bomber mission profiles (= level bombing mostly between 10,000 and 15,000 ft).

75...76.2 mm guns were often leftovers from the First World War, especially in France and the UK. Even the best guns in this calibre group lacked the ceiling to defend against American-style B-17/B-24 attacks due to the bombers' turbochargers permitting attack altitudes of about 27,000 ft. The calibre had such a low lethality with a time fused fragmentation shell that all the optical tracking, searchlight, radar rangefinding, computing and automated fuse-setting equipment of a heavy AAA battery would have been wasted on it. That is, unless one uses point detonation fuses and hopes for direct hits (then you need no automated fuse setters). There would still have been the ceiling issue, but the guns would have been deadly against large aircraft (medium bomber and bigger) within their reach at much lower expense than the next group. Everything changed for Western Allies' 76.2 mm AAA at about the end of WW2 when VT (proximity) fusing suddenly turned a 76.2 mm twin into a more effective counter-kamikaze defence than a quad-40 mm mount. 

85...90 mm guns were in another sweet spot that gave just enough ceiling (great ceiling if very high barrel wear was accepted) against almost every threat. The munition expenditure was terribly high per kill until late in war when Germany used impact fusing against large bombers*** and Americans created incomparably more expensive and sophisticated 90 mm proximity fuses that made the calibre effective against any target in range provided the fuse was not jammed and no ground features or waves triggered the fuses early. The calibre was used on some warships, but its usefulness against warships was limited to shooting illumination rounds at night. The shell was simply too weak against ships.

100...128 mm calibres were powerful with their fragmentation effect, but very expensive, bulky and heavy. The saving grace for this calibre group was the dual purpose potential; you could equip warships with these guns and plausibly use them both against aircraft and against any unarmoured ships at useful distances. Even 127 and 128 mm calibres were disappointing against unarmoured ships, but still accepted as barely good-enough for a naval DP gun. The Americans successfully used 127 mm guns as DP guns in the secondary artillery (against small ships and up to light cruisers) and tertiary artillery (heavy AAA) role, whereas Germany stuck with a 150 mm secondary and 105 mm tertiary/heavy AAA separation that yielded less guns for either role. The American 127 mm DP guns were unusually quick-loading and the first calibre to receive the new VT (radio proximity) fuses. Naval heavy AAA and DP guns were hardly worth their effort as AAA guns if not equipped with such VT fuses.

The Royal Navy used 133 mm (5.25 inch) guns as DP guns, but they were much less successful than the American 127 mm guns due to more sluggish mounts, smaller maximum elevation and lower rate of fire.

150 mm and bigger calibre heavy AAA and super-heavy AAA existed in marginal quantities with examples in Germany and in Japan. IMO such calibres should be limited to firing shrapnel rounds against incoming skip bombers and torpedo bombers from a super destroyer's or light cruiser's main guns (138...155 mm calibres, not real DP guns). These guns were so big, bulky and expensive that there was simply no realistic case for them being cost-efficient in a land-base AAA role. They were unsuitable for 85...90° maximum elevation naval turret mounting, so their AAA niche was a secondary capability of shooting at incoming aircraft within their elevation range (~30°) that was commonly provided for anti-ship fires. The USN introduced a class of light cruisers which had true 155 mm DP guns, but that proved to be inefficient and unsuccessful.

Surface-to-air missiles: Let's face it. The missile tech, guidance and fusing was simply not mature enough by WW2, but the experiments and the experience with the leap in aircraft speeds possible with turbojets showed that surface-to-air missiles would replace heavy AAA after WW2.

 

So all in all, I see for the WW2 period three different sweet spots for light AAA calibres (20, 30 and 37...40 mm), each dependent on tactical niches and two sweet spots for heavy AAA calibres (88...90 and mostly 127/128 mm with 100...105 mm being a very AAA-biased DP compromise), separated in land-based heavy AAA and naval heavy AAA/DP guns. Without hindsight, I'd likely have preferred 20 mm, 40 mm and 75 mm plus cruisers using their main batteries to shoot shrapnel at skip bombers and torpedo bombers at pre-set distances.

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Fast forward to today: 

Shahed 136-class cruise missiles can fly at 15,000 ft, above effective 40 mm gun ceiling. They are barely in reach of 57 mm guns. A modern 76.2 anti-aircraft gun based on the widely-employed naval gun and its munitions can easily reach Shahed 136 at 15,000 ft, but would struggle to reach and hit Shaheed 238 (more expensive, faster, higher, shorter-ranged) at their 30,000 ft service ceiling. Warships can self-defend against such cheap missiles even with small calibres (20...57 mm), but bigger calibres (76.2 up to 130 mm) are much more useful for protecting  escorted ships due to their greater effective range.

We need defences against flying munitions after land-based air defences obsessed about shooting at platforms (except in training) for generations. Something small calibre (up to 2 cm) makes sense for very short lines of sight (around treetop altitude), fairly compact autocannons can wipe clean the sky up to about 10000 ft. We need cheap guided missiles or the (unmanned) fighter approach to deal with higher-than-15,000 ft munitions without breaking the bank (which is what Germany did trying to defend against rugged bombers at 27,000 ft with 8.8, 10.5 and 12.8 cm guns).

A use of 155 mm (gun-)howitzers (which are equivalent to WW2 15 cm heavy anti-air artillery muzzle energy) for shooting down some munitions with special proximity-fused HE shells (normal PROX fuses won't work) should be possible, but this should be a mere secondary task for 155 mm guns.

S O

defence_and_freedom@gmx.de

*:  No better gun in the 37...40 mm calibre range was deployed after the Bofors other than its own evolution, the somewhat longer-barrelled 40 mm Bofors of the Cold War. 35 mm guns appeared around 1970 and excelled with much better rates of fire, but 40 mm remained the smallest calibre for proximity fusing until at least the 1970's. I don't know when 35 mm became viable for proximity fusing.

**: In the end, the Soviets brought a successful 57 mm gun into service soon after WW2. This gun has a much higher muzzle velocity than the German 55 mm prototypes. The Soviets quickly gave it radar and computer fire control and it's now again in wartime use in the Russo-Ukrainian War, presumably without the radar and computer fire control.  It's mostly used as artillery, but would no doubt prove highly effective against cruise missiles if equipped with functioning automatic fire control and proximity-fused munitions. The West uses a Swedish 57 mm gun in naval context.  

***:  Germany understood this very, very late in the war. All that fuse-setting equipment was wasted because 88 mm AAA was about triple as deadly against 4-engine bombers with impact fusing, 105 mm about double as deadly and the 128 mm calibre gained very little from it.

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A 'carry at all times' helmet for support troops in army divisions

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I hope you muted the video in time. Anyway, I showed this thing from 2022 because I remember having asked ballistic helmet manufacturers on Eurosatory 2018 why they don't provide a proper helmet for support troops.

Those hardly ever wear their helmets - on the head even more rarely than otherwise. Wartime videos shows that such military personnel does not even bother to keep helmets close by. So they simply wouldn't have ANY ballistic protection in the event of a surprise attack with things that fragment.

A compromise helmet that's carried on the body at all times (when awake) and sacrifices some quality to achieve this would be a great leap forward.

This mirrors what I wrote about 500 gram escape hoods to survive first 20 minutes of a chemical attack until you reached the bulkier & heavier 'proper' NBC mask and a PDW designed to be carried at all times (when awake).

A soft design would be even more comfortable than that origami thing and without gaps, but the trauma issue probably excludes soft armour from head protection until someone finds a non-newtonian fluid that's really suitable for body armour and affordable. 

A helmet that would be worn at all times would need to be lightweight and less bulky. A reduction of the protection rating from NIJ level IIIA even down to equivalent of PASGT 'flak vests' (less than NIJ level I, 15-20 layers aramid/kevlar) would be acceptable, or a reduction of coverage (as that origami thing would have; maybe -20% coverage). 80% weak protection would still stop 80% (by area) of 80% (most fragments are weak) of all fragments of an ordinary Russian HE grenade that a low cut thick adamantium armour helmet would stop.

NIJ level IIIA helmet shells aren't made of thick adamantium armour, they may stop only 90% of fragments (depends on the shell/mortar bomb and distance / also the rims are weak), so it's overall a reduction of protection from about 0.9 to about 0.64. The realistic comparison for a support troops ballistic helmet would be to no helmet at all, though - and that's an improvement from 0.00 to about 0.64.

Such a support forces 'carry at all times' (on the back, belly, on upper legs maybe?) helmet coupled with a 'wear at all times' flak vest (20 layers aramid, most times not closed, sufficient ventilation) would be a huge improvement for the protection of support troops within divisions in the field. A full performance mil spec helmet and (over-)vest could still be at the motor vehicle or camp bed.

S O

defence_and_freedom@gmx.de

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Simple WW2 infantry regiment arms

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I keep looking at historical army equipment and it's fascinating how simple the equipment even of an entire infantry regiment can be.

  

An example from WW2:

All an infantry regiment really needed (if I break it down to minimum required quantity of arms types) was:

• rifle
• submachinegun
• universal machinegun
• recoilless gun
• mortar

This can be further reduced with an automatic closed bolt action such as StG 45 had (a late WW2 prototype weapon, but not out of reach technology-wise by early WW2):

• battle rifle
• universal machinegun
• recoilless gun
• mortar

 

(c) 

Verein der Freunde und Förderer der Wehrtechnischen Studiensammlung Koblenz e. V.

Verein der Freunde und Förderer der Wehrtechnischen Studiensammlung Koblenz e. V.

 

(c) Pollyanna1919

source https://www.lonesentry.com/articles/ttt07/recoilless.html

 

source https://dic.academic.ru/dic.nsf/ruwiki/1414802

  

(Keep in mind mines, demolition charges, rifle grenades and hand grenades count as munitions rather than weapons. Flare guns were a tool rather than a weapon outside of German armed forces. Pistols were not a serious weapon post-1871 and irrelevant by WW2.)

 

Moreover, recoilless gun and mortar could be had in one calibre (90...120 mm smoothbore), sharing some fuze and grenade designs and not needing any expensive rifled barrels. A 105...120 mm smoothbore recoilless gun would excel at using shaped charges for anti-tank work out to about 500 m distance (moving target, 1 km against standing tank). A rifled one would instead be able to penetrate 100+ mm of RHA with a HESH/HEP approach.

 

The whole arsenal of such a force could have been produced in backyard workshops save for the supply of unfinished steel parts including barrels. (Again, munitions excluded, but TNT, mercury fulminate and cordite are enough and all simple 19th century tech.) No extraordinary skill was needed, one fully qualified gunsmith, one metalworks machining instructor and maybe one welder would have sufficed to train the entire workforce via snowball system. The only extraordinary production tech was the then-new stamping (particularly for the StG45 - modern machinery, but usable by unskilled labour). 

    

The most difficult equipment to produce for such an infantry regiment were probably the radios with their rechargeable batteries. The typewriters were quite complicated, too. And then there were the motor vehicles, but those were still optional during WW2.

 

You may think something is missing - air defence. Actually, effective air defence (better than ordinary machineguns) was hardly ever present in WW2 infantry regiments. A well-rounded one could have had something like the Madsen 20 mm M/38 for keeping ground attack aircraft at 1.5 km distance and dealing with nimble armoured cars, of course.

 

BTW, historical WW2 infantry regiment arsenals weren't that much more complicated. Again excluding pistols and flare guns, about seven weapons types was an ordinary diversity of arms types. 

S O

defence_and_freedom@gmx.de

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Army vehicle size limits

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It's often said that the CVR/T tank family of the British was required to be narrow enough to fit between the rubber trees on Malaysian plantations due to the British experiences in the late 40's conflict there.

(c)Irish Defence Forces

I don't care whether it's a myth or true - it inspired me to think of what we should require regarding vehicle maximum sizes in Europe. I do explicitly exclude heavy logistics and support vehicles as well as tanks here; just thinking of common battlefield used by forces in or close to a battle such as cars and APCs.

The war in Ukraine has shown the importance of being able to hide troops, vehicles and supplies once again. It also had and has a substantial share of combat inside woodland, even including tank actions.

 

Garage doors aren't standardised even in Germany, but they are very commonly sized to fit at most a medium-sized SUV.

Doors aren't fully standardised either, but there's a certain common size that could inform requirements regarding UGVs and all kinds of manually-moved containers on wheels belonging to headquarters, field kitchens and the like.

One thing is for sure: We should NOT permit battlefield vehicles to be needlessly too tall for concealment. Vehicles so tall that to disguise them as a building is the only promising approach should not exist. 

"Boxer" - some geniuses want to add a turret on top

S O

defence_and_freedom@gmx.de

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